# What is wrong with this picture



## Mayhem

Background: I stripped down a couple of old PAR 56's on the weekend and found the following:




I apologise for the poor quality of the image (looking at the lamp base on a PAR 56 MFL lamp) but this is the closest focus I could get and I didn't have a tripod handy - so you'll just have to look past the camera shake.


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## len

Am I seeing bare wire just wrapped around the post? And it still works?


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## JahJahwarrior

oh my goodness!!! wow! no solder, no electrical tape,nothing to keep you from getting shocked....that's hilarious and dangerous at the same time!


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## digitaltec

Ok, it would not be a PAR Can if there was not a risk of electrical shock! It practicly says that on the label.


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## soundman

I see no ground wire, it sould be on the metal housing though not the lamp


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## Mayhem

Ok - still looking for a bit more depth in the answers but you guys are on the right track. 

Also - look at the second terminal. It has heat shrink over it, as did the first one. However, I cut away the heat shrink so you could see what was hidden by it.

Yes - the PAR can did have an earthing strap that was in good condition and correctly attached.


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## SuperCow

Well there's a lump in the bulb to the left of the wires. Is that what you mean?


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## sound_nerd

not using high-temp wire? I dont know if that matters for par56's......


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## soundman

been a while since I have changed a par bulb, is that gold tumor normal?


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## sound_nerd

i didnt notice the tumor..... hmm.


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## Mayhem

The colouration and "lump" are normal and the lump may even have a function other than being a casting mark. However, I don't know, so if anyone does know now is the time to speak up.

The question I am asking is in relation to the wiring of this PAR lamp. I don't really want to give the answer just yet as I want to see a few more responses. 

If you think that something is wrong, say why you think it is wrong, what the possible consequences could be and what the fix is.

Don't worry about being wrong as you will probably point out something that I and other had not thought about.


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## sound_nerd

its the type of wire used i'm pretty sure.


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## digitaltec

The positive and negative are reversed? It also looks like it was J-hooked or something funky. Also normally, I would not leave bare wire. Meaning that I only expose the amount of wire needed to solder or attact to the post, etc. 

This is really starting to bug me given that I should be able to figure this out. I guess I have been fixing one to many movers and forgot about the basics. :roll:


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## soundman

Its singel strand when it should be hulti, leading to it getting bent and work hardened? polarity shouldnt matter, current is  no matter which why it flows through a bulb which is why some lights have two white wires and a green one.


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## jmsinick

My random thoughts/observations in no order:

1. where is the creamic, and why did it break?

2. the heat shrink does not extend all the way down to the lamp, where someone could reach in and get a good shock, or the lamp would short out

3. the lack of a creamic connecter takes away a means of dispersing the heat

4. why would someone go through all of this work for a par lamp, it seems as if it was ment to be semi-permanent, which is a very bad and unsafe thing. I would not even trust this as a temp fix because there are too many things that could go wrong

5. the terminal looks as if it has been slightly pulled out of the lamp

6. if this lamp were to burn out, it would suck to try to relamp it if it were in the air and unable to come down

overall, this just screams unsafe!!!!

Jeremy


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## ship

“Ok, it would not be a PAR Can if there was not a risk of electrical shock! It practicly says that on the label.” - Chris R. Ubinger 

I was just playing around with a Kupo lamp cap handle today. Bought them in bulk really cheap for an install and while it did not fit well on my own lamp caps due to it being a different brand, they did still work well. The vendor was telling me that they have to sell PAR fixtures now with a screen over the lamp cap opening as the only way to get UL listing for the fixture no doubt due to similar problems. They have to sell it with the screen which they recommend to the customers that they just remove if not replacing it with the removable lamp adjusting knob. Don’t know why UL would require a cap when other companies such as TMB or Thomas and even Penn Fabrication don’t need to have them, but it’s a valid objection.

www.moonlightusa.com Look for the PAR Can exploded Pictorial. Very cool clip on lamp swivel tool given it fits the cap of you can. Even if it does not match the opening, it still functions for my needs in keeping the bulk of snow out of the cap. Takes me back to some old Colortran PAR fixtures that had a handle that allowed you to swivel the entire cap in relation to the can. Nice fixtures.


“Yes - the PAR can did have an earthing strap that was in good condition and correctly attached.” - Mayhem
I have found a constant problem on par cans to be that the earthing/ground wire while there becomes loose far too frequently in even if connected still being a high resistance connection in not doing any good. Always good to check to see if the rivet on the ground is loose and moves when changing lamps. When loose replace or in my case, I use a actual green grounding screw from the normal electrical industry and a stainless steel top lock nut that firmly locks that grounding ring into place. This with a high temperature ring terminal works well.

“not using high-temp wire? I dont know if that matters for par56's......” - sound_nerd
hmm, How hot can a 500w lamps get anyway???

“The positive and negative are reversed?” Bi-pin lamps don’t have a positive and negative, or in AC power terms, a hot and neutral.

I’m beginning to wonder how many people on this forum even have a PAR 56, or PAR 64 using the same lamp base. By the way as described to me, this 16ga solid core wire was pushed thru the opening in the lamp base pin hole than covered in shrink tubing. 

Jeremy is getting close, touched on the subject but needs to think less about specific details in heat and more in general on how someone solved a problem they had.


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## sound_nerd

Someone had a can with broken ceramics, and needed it immediately for a show or rental. They rigged this up as a temp. solution and either forgot about it, or decided to leave it. Am i close?


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## techieman33

not to get off topic, but if i'm correct, the hot and neutral do make a difference, i have been told that if it is wired one way and then rewired opposite it will greatly reduce the life of the lamp.


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## sound_nerd

maybe, but when initially wired it shouldnt matter which terminal you use for hot, and which for neutral.


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## JahJahwarrior

looking at it again, it looks hardwired in, like, there is no cermaic plug thingy that the lamp is pushed into. Not only that, but the wiring is single strand, and I know that even normal extension cables in the US are multi strand. Futher than that, ,if they were trying to fix it, ,tthey could have atleast soldered it on to ensure a good connection. But atleast you said it did have shrink wrap on it....hey, did it come like that from the factory?


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## DMXtools

I'm assuming the white is the ceramic connector that connects to the pin terminals of the lamp proper. The focus isn't quite good enough for me to be sure, but I think that looks like solid, not stranded, wire. Stranded would be better, but either way it should be soldered to the connector terminal. If, on the other hand, the white ceramic is actually part of the lamp, it looks like instead of connectig the wire directly, it should be crimped into the proper size insulated "faston" terminal.

John


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## ship

“not to get off topic, but if i'm correct, the hot and neutral do make a difference, i have been told that if it is wired one way and then rewired opposite it will greatly reduce the life of the lamp.” - techieman33

There are 152 types of lamp base currently in use ranging from B22d to Wire Lead. Given this, a steadfast rule that applies to all will be not be appropriate. There is some basic principles about lamp bases and lamps however. 

First, this is alternating current. In other words, the power heads in one direction, than reverses itself and goes in the other direction 50 or 60 times a second. In other words, with AC power, the power does not go in from one end and out another though it’s easiest for wiring principals to consider it as doing this - one end in, one end out. How ever you consider it, a filament lamp working under AC power 99.5% of the time won’t matter which side you attach the hot to because the filament will resist the current flow no matter which side of it gets the power first for 1/60th of a second as opposed to the other side of it getting power for the other 1/60th of a second next. 120v AC current works just like 208v currrent and other types of current except instead of having two hot wires feeding the filament 1/3 out of phase with each other, the 120v lamp only has one hot. Both types of current still have the current going back and fourth in feeding the lamp.
This is not the case with DC power where the flow goes from the negative to the positive. In cases like this while any AC lamp will work under DC power, there can be at times DC lamps specifically designed for a direction of current flow in preventing any filament notching that might happen on the power in side as can happen given the single direction of power. You will probably never see such a lamp used on stage and for general purposes such a consideration is not to be worried about.

So why does it matter at times which wire is hot and which is neutral on a lamp? This goes into the nature of the lamp base design. Your medium screw E-26 or E-27 household lamp has a 1.1/16" dia. (26mm) for American lamps, Screw thread and a contact plate at the base of it. Same with a Fresnel’s Medium Prefocus Single Contact P-28s lamp base which is also about 1.1/16" dia (27.4mm Dia.) In having a wide skirt at the top used to lock the lamp into place. You will also find that center contact plate on this lamp. For the most part, the screw base be it from E-5 Midget Screw to E-40 European Mogul Screw and pre-focus single contact point based lamps from P-14.5s to P-40s are the primary consideration for having a specific hot and neutral. There are other types but these most explain the rule. When you remove one of these lamps from it’s lamp base, there is a chance that you will touch or come into contact with the screw thread. Were this pre-focus fin or screw thread hot, you would probably get shocked. Having a rule that the neutral goes to the shell than makes sense in protecting the user’s of the lamp from shock.

Most other lamp bases other than these two types will not matter which side is hot and which side is neutral. Stick that GX-16d Extended Mogul End Post/EMEP lamp into a base, and both pins are the same side. Stick that Leko lamp with a Medium 2-Pin G9.5 into it’s base, and both pin holes are also the same size. Given both pins are alike, than wiring one side with a specific hot or neutral will not matter because there is no way to ensure the lamp will be inserted in one of the two specific ways. This also covers such lamps as RSC / R-7s / R75 type Recessed Single Contact Double Ended Lamps such as many people would be using in cyc lights or even construction work lights, down to the wire lead lamp bases used on your Christmas Tree. 

This said, there is like with the position orientated prefocus Fresnel lamp bases above, bi-pin and other types of lamp base which use a position orientation system to help ensure the lamp goes in in a specific way so as to optimize the filament’s layout in the fixture. Such lamp bases as say a GY 9.5 Skirted Medium Prefocus 2 pin which is similar to your Leko lamp in style has one pin 3.2mm and one 2.4mm in dia. instead of both pins 3.17mm. In this case, besides having the pins of different diameters to help position the lamp in the fixture, you would tend to want the hot wire going to the larger pin because this has the primary amperage on it.

Given the specific pins, such lamps might also be optimized for current fed from a specific direction in there being a possibility to what you were told, but not many of them would need to be. What ever the case of some very specific lamps, all PAR lamps have two pins of an equal size and it will not matter which is hot and which is neutral because one end of the filament is the same as the other end of it. 

Hope it helps..
Brian Shipinski

(Festoon terminals would also be the wrong answer also.)


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## ship

What by me posting do I shut down the discussion period by way of intimidation or something? My intent was to educate and answer questions to what's posted but not solve the problem. A problem that as yet is still not figured out. You are tech people, much less most of you are specifically lighting tech people, why is this thing unsafe?

One last day or two to answer before Mayhem tells you why this thing ain't proper. Much of the ain't proper has been hinted at but is judged to be skirting the absolute and most proper answer along with the subsiquent answers as to why what was done in being improper even if wrong is improper. If you already posted, have another look and try again in refining your answer or being more specific in symplicity. If you have not posted but think you have a idea of why you don't want to see this, as you can see, while I might hop on and explain things further, you certainly are asked to help solve the problem in broading everyone's education.

Edit: send photo to dvsDave and he got them up here!





Here is another one I saw today that I did not get a photo of. A professionally made stage pin threefer male plug was taken apart today in replacing the hot pin which had broken within the plug so as to become much shorter than normal by way of breaking somewhere within the plug. It was noted upon opening up the cover two things. First that the pins were crimped to the wire so there was no chance of a loose pin to the below. Than that the wire was oxidized and the outer insulation on the wire was completely burned off and flaking off the oxidized/burn hot conductor up until it hit the strain relief.

What's the cause of this wire becoming over heated on this threefer to the extent that the insulation on it dry rots than flakes off within the plug, much less the wire oxidizes in over heating? There is two possible causes for it given it was a crimped terminal thus this plug's connection to the pin was not the cause.

Given the hot's insulation as far as could be seen that was stripped from the outer covering on the wire was over heated, what than would determine which of the two possible causes for the melting of the hot pin/wire was the cause of the threefer's failure? In other words, what simple thing can you do which will show the cause if not even if it's safe to cut the wire and just add a new plug to it?


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## sound_nerd

we havent heard a reply from Mayhem regarding if anyone was right or not.....i think most poeple are waiting on him.


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## avkid

not grounded, the twist in the wire is not safe,the ceramic retainer is not a complete one


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## ship

By the way in adding a second topic to the subject of more than one conversation going on at once some hate seeing, there is a third option I had not thought of at the time but did later become another option to cause the melt down of the threefer. In this possibility the fact that the pin gapping on the broken hot pin was also squeezed together would be a hint in it's possibility as a factor once the pin itself broke it's mount and became shorter. Three options now for why the cable went bad, still one good way of confirming at this point one of two reasons for it at this point was not the cause. If it would be of use, I'm sure the plug is still in my trash can and I should be able to post the picture.



On Mahyem's post, don't worry, he will post the anser within a few days. Until than, don't rest on your answers because while some were close in telling the details of to date or finding the answer but not seeing it as the answer, (including those just before this post.) None to date have said what's specifically wrong with his picture. The lamp itself for instance is not something to be grounded.

If of help, I'll post a reward - some swag to that person that either re-defines their answer or answers the question correctly to Mayhem's post or figures out at least two of the three possibilities of my description. And when I send swag out, it's more than a single item worth of it - normally it's a overloaded box of it.


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## JahJahwarrior

things I notice that seem odd to me: 

1) unlike most lamp fixtures, this lamp does not have a ceramic plug that connects to the Par lamp. Instead, the wires are connected directly to the lamp terminals. That in itself seems wrong to me. 

2) these wires, in the first place, are not soldered on. IF you were going to connect wires directly to the lamp, and go through the whole bother of putting heat shrink on them, then why don't you solder it, so it is atleast a LITTLE more permanant?? 

3) the other thing I noticed about the wires, which is not necessarily wrong, but it does seem odd, is that both wires are red. Now, I konw the leaads to the ceramic plug are usually the same color, if that is the reason for these both being red, then ok. But, where is the ceramic plug then? didi it break and they connected the leads directly to the lamp? Or, did it never have a cermaic plug, and the light company was saving money by selling lamps already installed in lights, without the ceramic plug? or, ever wrose, could those wiers both be hot? That would either blow up the lmap, or atleast make it not work at all. The wires also seem long to me, beecause there is not a cap thingy in the picture, nor infact any other part of the fixture. 

that's really all I notice. And ship, with the threefer, i have no idea  i don't use stagepins at the places I run lights, so I'm not too familiar with them anyways. but you seemt to know what your problem is anyways  man, I hope i'm not missing something EXTREMELY obvious about that lamp...I've been working on a few pars alot recently and I really don't noticec anything odd other than what I've already mentioned.


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## Peter

A reward? hmmm cool... I'll have to take a wack at this then, even though I have never seen what one of these is SUPPOSTO look like.... 

Is it me, or are both of the wires comming out of it red? Shouldnt they be two differnt colors? 

The wire twisted arround the terminal is something that is obviously not a very safe idea.

Also, the Terminals (at least the closer one) appears to be pulled out, and probably not as secure as they are supposto be.

I think it is just generally unsafe!


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## Peter

Grrr....  JahJahwarrior JUST beat me to the two red wire thing..... 

And Ship, I really dont know what is going on with your plug. I am not sure if I understand what you are describing. (though it's probably just me being unfamiliar with the inner workings of plugs)


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## JahJahwarrior

haha! dude, no competition! i'm not expecting to be right, I just keep looking at the hints Ship gives, and I've rad that post right before his lst one more times than I can count, and I can think of no way to go deeper into what I've already said. if I haven't found something wrong withit yet, then I might never  the biggest thing to me is the lack of a ceramic plug! that suprises me ALOT! 

anyways man it's all good and Ship or Mayhem, could you tell meif I'm still on the right track? specifically with the ceramic thing...I think ALL of us are wondering abut that one!


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## soundman1024

*uhh*

The wires go straight to the lamp, no connector.


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## disc2slick

that last post was me. forgot to sign in, whoops.

-dan


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## JahJahwarrior

wwell, I agree with you dan, except that if it was just for a day, and you really needed the light, and you knew that it would not be on for long, it would be ok in my mind. There are just points where something breaks and you have to fix it, but the key to that is you have to GO BACK and REDO it later!  For example, I rewired a Par the other night, I did not have electrical tape. The lwires were not in a placee where they would be touching and I purposefully made them long (these were the leads from the ceramic to the cable thingy) so they would stick out the back a little so they would not heat up enough to melt the duct tape I put on them. (this was a soldering job done to splice to cables) now, I am going to back, possibly tomorrow, and redo that with electrical tape. My solution works, but only because of the other measures I took to ensure it would be safe. This solution in this lamp sould not have been used for longer than one show, it should have been marked down as still needing repair and been repaired properly before further usage. 

So, the one thing we have figured out is something IS wrong!  now, we have all made guesses (well, they are more educated than a plain guess, more like hypothesis) about what is wrong. Mayhem or Ship, can youo tell us once again how close we are??


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## sound_nerd

what was suporting the lamp inside the fixture? Was it supported by the wires alone? Was there any sort of strain relief? I hope it wasnt these wires (which look like nmd14/2 but i could be wrong) that were coming out of the fixture and into the plug. I think the one major problem with this is that without a ceramic base installed.....what was keeping the lamp from falling out? My guess is that it was the wires. Thats a scary thought..


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## JahJahwarrior

the lamps are held in with a ring thingy, and also on some fixture there is a wire screen in front of them too. The lamp should have been held in fine.


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## Mayhem

Ok – well I may have added some confusion to the post by taking the lamp out of the can. I did this to better show the problem, so I actually just cut the wires off and lifted the lamp out. 

The main observation here should have been that there was no lamp base fitted. 

This would have then focussed your attentions onto the issue at hand. The white ceramic block was actually the base of the lamp, from which the two terminals project.

The correct answer is of course that the method used to wire up this can was unsafe. Here are the reasons why:

1.	The way in which the wires were attached to the lamp terminals: The twisted wire could have easily come lose, which would have caused arcing and blown the lamp. A ceramic lamp base should have been used which provides a fully insulated connection. Imagine having someone place his or her hand into the back of this can to rotate the lamp.
2.	The heat shrink is not rated for the temperature and would have eventually cracked and fallen off. This would have then made it easier for the wire to work lose, with possibly devastating effects.
3.	The wire was solid core (well spotted) and its insulation is also not rated for the temperature. It is also intended for installations where the cable is fixed into position and is not subjected to twisting. 

A couple of other issues to note – whilst crimping on a suitable connector or even soldering the cable to the terminals would provide a better solution to simply twisting them on (and a much better electrical connection), it still isn’t a safe way of doing things in this application.

The two solid core wires were in fact soldered onto the active and neutral wires of the tail of the can. As Dan pointed out, this person knew enough, but not enough. Although, this is the only can out of the four that I “rescued” that did not have a lamp base and was incorrectly done. 

A lot of you picked out some of these faults, but I was hoping that you would have said why they were wrong. That aside, well done to those who were heading down the correct track, and thank you everyone that had a go. If you like this sort of visual problem, I am sure that we can find some other probing questions to answer.


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## soundman

In reply to ships question was the load above what the cable was rated for? Seems too simple to be right.


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## ship

soundman said:


> In reply to ships question was the load above what the cable was rated for? Seems too simple to be right.



That's one of three possibilities - especially on a twofer or in this case threefer no matter what plug style is being used. Any time you have the ability to plug in more than one thing, you have a added possibility to overload it. Now the question would be how you can confirm this assumption?

I will attempt to take a photo of this plug in the morning and post it.


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## soundman

check the wire ga verse the breaker. If it was 14 ga wire but a 20 amp breaker that would be on the top of my list. Also estimated draw, if they were being used for some non dim circits like moveing lights or a fogger the amps cann add up, espesily when some knuckel head puts in another split down the line.

I dont know if I am reading your post right but you say the gap on one of the pins was not there could that have created enough of a gap to create an arc and then the heat would be responsible for the damage to the wire. Look for signs of welding on pin to be sure.


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## ship

12ga SO wire on a commercially made molded twofer and all you have is the adaptor after it comes back from a show thus in a post use way.

In the second paragraph you are getting close to the third reason. Re look at the first description.


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## soundman

there wasn't a lot of contact because of the crushed pin. This caused friction (electrons moving and what not) and metal being the great conducter it is carried it to the wire. Thats just a formal restatement.

Was the cable in the elements at all?


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## JahJahwarrior

unable to resist the offer of swag, I am thinking about the threefer as well. Ship, I am wondering, is there any possibility of something being wired wrong outside of the threefer? like, one of the lamps it was plugged into? Like, could one of the wires have been reversed or something? I would think that if something like that had happened it wuld have hurt the lamp as well as the threefer so i don't view it as likely. my other wonderment is, could the problem have something to do with the breaking of the pin? I, not knowing much about stagepins, know that the pins are varying distance sform each other. so, it doesn't seem to me that it would fit in backwards, but could there have been some other problem to push the pin in and break it? like, could the thing he was plugging it into have had some sort of crap in it's female positive end? Something to shove the pin on your threefer in? perhaps he had another broken stagepin in it  and oncec the pin was pushed in, could it have managed to touch any of the other wires in the stagepin? because that wouldn't exactly be good


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## soundman

If the oxidation was a preexisting condition that would have turned the wire into a resistor/heating element. sorry my posts lack structer im kind of brain storming.


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## JahJahwarrior

sadly, I am no expert on electricity and oxidation...but, would oxidation only occur on the hot wire if the wire was wet while operating, or would it occur on ALL wires?? if it would only occur on the hot wire, then yeah, I think that soundman could have a point with it becoming a heating element like thing...now, ,why exactly did it oxidize? i know you don't need water for it to occur, but my first thought would be operating in a wet spot or in the rain or something. can any of you answer my first question? thanks!!!!


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## soundman

All metals oxidies, some just faster than others. MY thought was that if the cable was moist it would have oxidiesed faster than normal. Does that help?


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## JahJahwarrior

could it have oxidized that much in one show, presumably one-2 days, operating three lights at the maximum rated load of hte cable for a good deal of that time, if it was in either a very moist spot, or indeed in a small puddle? or if some watter got in it briefly and although they cleaned theoutside off, the inside stayed wet? and why did only one cable oxidize? i know metals can oxidize almost instantly given certain circumstances, but could this metal have oxidized that fast in these cirumstances?


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## Mayhem

Think along the lines of physical contact - how a plug mates with a socket.


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## JahJahwarrior

well I was wondering earlier why/how the pin got pushed in. Could there have been some crap, possibly another broken stage pin, in the female plug this threefer was pushed into?? could there have been a short or something in another cable that caused the hot cable on the threfer to oxidyze??


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## soundman

were you able to get pics?


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## ship

Pics are taken for what they are. Waiting on Dave to post them.

Waiting on them to also comment much further about pins pushing in to be a cause and other things. Getting close to one of the possibilities, just not well thought out as to why yet.

On another possibility, a short at the fixture probably won't bother the plug two or three feet away from it even if directly attached to the fixture - it would most likely bother the male plug to the fixture and the female plug attached to it by way of heat. Probably won't being an operative term as if this caused a serious overload at the threefer because of the extra current it cold potentially also take out the threefer plug. Not because of the heat effects of the short but because of the overload in current now traveling thru the threefer going to the bad fixture and to the other things attached. A question of how bad that short first in what's taken out first - the fixture and it's plug or the threefer. In any case, it's also getting close to an second if not third possibility of the threefer's failure.

Still three potential causes of it and one specific way to rule out one of them which has not been recognized yet. A second thing you might note that could cross out the second one. Given the picture however it will confound and make it more confusing yet because the neutral I had not noticed at the time is also burned up - but not the ground. Nor is the plug in any way melted down. 

Only damage to the plug is in the area that holds the hot pin in place It broke in allowing the hot pin to slide backwards some. You will also probably not note but have it noted that the pin spacing on the hot pin is smashed together. This is what's necessary for a tight connection. The pin itself looks like it got heated red hot for a period of time due to discoloring. The insulation off this pin and for some reason also the neutral having this heat also flaked off.

The plug was factory installed and was of crimp type thus there is no chance of a loose set screw in crimping wire to terminal. Strain relief was tight but not too tight, and the outer jacket on the wire at the strain relief and away from it looked to be in good shape.

Any help in re-stating the observations?


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## JahJahwarrior

man...i reallyuy feel stupid, first ic ant' answer very well the par question, and now this too....

but it's ok for the two sides of the pin to touch, ,right? i have seen stage pins, just not much. It sounds like the dude pushed it into a bad socket or somethig, pushing the two sides together because the hole was too small, and pushing in the pin because of some obstruction in the socket. i kow what crimping is, but i do not konw how you crimp the wire to the pin. ir eally can't think of what exactly the problem could be....is there anything really obvious that i am not noticing, or that i have touched upon but need to develpto more?? ?


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## soundman

Can we rule out something random like someone taking al ighter to the plug? 


Plug has heat damage to wire and the plug is broke
Was plastic melted or was it cracked off?
If melted pin holder damage could be result of problem if cracked I would suggest it is the blame. 

Where there any signs of damage on the outside to suggest that the problem did NOT origant inside?

Still strugling with a way to catc to see if it was too many amps, with out knowing where is was in the show some one could have abused it with a few differnt conectors. 

I would chop off the broken end and bad wire and just make a new one as long as the wire is up to standerd.


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## ship

At some point I hope the pictures are posted. I’ll send them to Mayhem tonight to see if he beats Dave to the task on posting them. I was once sent a step by step set of directions for posting pictures here and it went right over my head. If I can find them, I’ll attempt again. 

So far you both are doing just fine in thinking thru a problem and have at all times been right on the cusp of an answer. Perhaps not the proper technical answer or the specific cause of it much less the three possibilities for the cause, (might be four at this point) more in a related to and similar things centered around the same things one might notice, but still right on the cusp of an answer.

There was no damage or melting to the plug body itself except that the retaining part at the rear of the pin was broken - not by way of heat (probably); more from concussion such as from an un-lucky dropping of the adaptor on the pin in just such a way. Than again the pea and the princess type theory of something inside the other connector or something wrong with it is also a possibility in causing it to break and slide backwards. In this pin sliding backwards on a Bates plug - because there is different types of plug design thus it’s important, there was lots of room behind the pin for it to do so without shorting to another conductor. Shorting within this plug is not the cause given no shorts were noted where the conductors come back together at the strain relief. In looking at the conductors at the strain relief, if too tight or conductors were nicked while the wire was stripped, this could be a cause in other situations but not in this case. 

Specifically in a too tight strain relief, the malleable material such as the insulation around conductors if forced out of the way - I have seen as little as 1/32" of insulation between conductors on cables carrying 20 amps and more given the rest of the insulation is forced out of the way. That strain relief holds really tight up until the insulation it’s forcing out of the way, at least the remainder of it allows the insulation to melt away in a dead short. Than it’s loose again once it’s done melting. (Always read and follow the manufacturer directions on doing a strain relief. Them little slips of paper are there for a reason, if you have not read it, perhaps you should because there is frequently details that are needed to know. Now if I could only get “professional” tech people to do so. They know what they are doing by way of making their living at doing so - “you trying to tell me my job?”) This especially becomes a problem where the wire flexes right next to the strain relief. Conductors move as the wire flexes and if the strain relief is too tight, they can cut thru what little insulation is left between conductors as the conductors move. Been there, done that on 208v plugs, not pretty. 

In nicking the wires you strip, even if not all the way thru the insulation, with use and pulling on the wires, those nicks open up in exposing wires. All you need than is either moisture to bridge the gap between conductors or sufficient amperage for a short to occur. As said however, both conditions were not present. Such things were the subject of a PBS special on why some planes started falling out of the sky. In either case, it was noted that neither was the case.



The pins of these plugs a little gap or slit cut in them which serves two purposes over pins of say a Cee Form pin and sleeve plug that does not have any slits cut parallel to the length of the pin.
The purpose of this slit is two fold. As the pin gets heated up with current, it allows for expansion and contraction of the pin without adverse effects to it. Second with this slit, it allows some amount of spring to the pin both in retention in the socket, and even when hot and expanded, allowing the plug to be removed.

To maintain a proper tension plug to connector, it’s necessary for this slot to stay parallel on each of the pins that join with a socket. With use and abuse this gap in the pin frequently becomes crunched together. Ever hear about not dropping your cables “clunk” on the stage deck? Beyond possibly breaking the pin loose from it’s housing so it slides backwards within the body of the plug, or even breaks the outer shell of the plug, such dropping can cause the pins to bend or gap to squeeze together. This stepping on them etc.
These abuse issues and lot number differences between plugs of a specific date in alignment with plugs of another date; much less wee bit of differences between one brand joining with another while the slotted pin will compensate for some of it, does cause the slot in the pin to be squeezed together at times in use. No big thing take out your handy pin splitter and correct the problem. Short of re- slitting the pin, it forms a sort of cone shape in two of the three dimensions. In having a cone shape fitting into a parallel slot, naturally it’s going to have less surface contact with the other sleeve it’s connected to. This less surface contact can have a certain amount of heating effect on the pin when under load but normally not sufficient enough to cause failure. Something to watch with these male pins, but not something that’s normally going to burn down a building. The other reason to watch the gapping of a male stage pin is because of tension reasons. If the plug does not have a bit of resistance as it slides home into a female connector, it might slide out during a show, much less either it or the female connector’s gapping is in proper in causing even at times the current to jump between socket and pin which causes a lot of heat. These arcs will tend to either weld the connectors together or cause pitting from welding on the surface of the pins and sockets. Pitting is also a bad thing in removing surface area to conduct electricity.

Raised sections from the welding will tend to prevent the other than raised sections of the plug to contact the female part of it, pitts and recesses while less dire remove that amount of area from contacting the other conductor. That’s why you don’t hot patch or in other words plug in or remove a load from the power source. In doing so you tend to arc the conductors together in causing this at the first point of contact. This arc welding can prevent the surface area of a pin from contacting a sleeve with sufficient amounts of contact. (Need to test a fixture, install a switch that is designed to turn power off and on. Need to check a fixture, turn the dimmer off.) 

Specific to this problem, while the male hot pin was squeezed together, there was no arcing observed on it’s surface, just a change in the color on the pin due to heating.

This heating can be because of a loose screw in holding the wire even furrled wire to the pin or sleeve/female connector. The wire without good contact to the pin it’s attached to tends to heat up in an extreme when current flows thru it at a high resistance due to the means of clamping. Never put a bare wire under a set screw, never over tighten it. In over tightning it, you cut into the conductor and by way of pressure on it or specifically those conductors most under tension by the screw, you cause a high resistance load because some of the conductors are really clamped hard together, and some are not as tight. In a loose connection, none of the conductors are really tight to the screw terminal. As above, some less than others unless in a ferrule or wrapped in holding the conductors together in a similar way. 

Remember that current follows the path of least resistance. Since a wire is a path of least resistance it tends to follow it as long as it’s easy to do as if a water hose. Clamp down too tight on the hose and the water will wish to find another place to escape. Clamp down too loose on the fittings and it’s also going to escape. This escaping energy becomes heat in the form of resistance to the current flow. I have another set of pictures TBA demonstrating this in the case of a 100 amp distribution block when these conditions and others were found on a three phase 400A distro panel.

In any case, given current follows the path of least resistance, it will also tend to flow down the outer round surface of a conductor because of this. This term is the term “skin effect.” There is less resistance to current flow towards the outer parts of the conductor than in the inner parts of the conductor that’s all copper and no air as it were. Never cut down the outside of a conductor cable so it fits within a lug that’s too small otherwise to fit. When absolutely necessary to make the cable smaller, always cut the inner conductors and bend the outer conductors inwards due to this skin effect while tying in power (later). 

In the case of a high tension clamping of the wire to the plug or any terminal of it, you squeeze a conductor in high resistance because of the skin effect. The current will still wish to flow to the outer edges around the pressure applied by the set screw. Some parts of the conductor will be less clamped than other parts of it especially when you don’t use a ferrule or similar means to ensure all conductors receive the same pressure. The current will naturally flow to these parts of least resistance. If the conductors are not clamped sufficiently, the individual strands both under screw terminal and strand to strand will than ac to each other in jumping the current. This arcing than causes heat which melts the conductors jumping in the current which further causes resistance in even more heat yet. 

(Note: this is a very important concept to understand by way of lamps fitting into sockets or any other electrical joining of materials that other wise are individual conductors.)

Clamp the conductor too loose, and you have the same problem as above with little arcs of electricity following the path of least resistance much less any movement with the cable will tend to make a higher arcing contact point with it. Once you get back to the wire from this clamped junction, you also get back into the classic skin effect of the current traveling around a round outer surface of the wire. In going from clamp to round conductor, you get into problems mentioned above about cutting those outer strands of a feeder cable about what happens when the current has in a cable to get between the area of the clamp, less supported outer areas of a plug or even inner conductors of a cable that now have an outer layer to go to in a thinned out conductor. This even to the point of broken strands of wire tends to cause heat in the current following that path of least resistance going from say a flat section of it with the outer edges less clamped and often broken than to the outer edges of the round wire. Lots of resistance to a easy flow of current here.

Also in a turning screw clamping down on individual conductors of a stranded wire you tend to get the cutting effect on the wire that happens as the screw turns it’s way into clamping. Another reason for using a ferrule or sleeve around the stranded wires. That said, a ferrule that’s too large to clamp the conductors won’t really support them in keeping them tightly bound under the clamp, nor will the ferrule in not having bulk around it’s cylinder prevent the screw from just cutting thru it as if it were screw going into individual conductors. 

For this reason, say if I’m wiring a lighting fixture that uses 16ga wire, I don’t just use the 12ga ferrule unless I double up the fixture’s 16 ga conductor to 13ga a much closer fit, because the screw in clamping down on it will just cut thru the ferrule and even use the ferrule’s sharp cut thru edges to further cut into the wire conductors. Instead I use a 16ga ferrule sized for the wire with the 12ga ferrule sleeved over it so as to provide both a larger area under the set screw for it to hit and also for more metal in using two ferrules for that set screw to tighten into. 16ga inner sleeve than bands the wire conductors so all receive about the same amount of pressure on them, the outer sleeve closer fits the opening in the hole and provides a second layer of metal between screw clamping down on it and it just cutting because there is no support under it.

Think of the use of a ferrule as similar to the mechanical advantage you might have in clamping a piece of rope to a woodworking C-Clamp. First the strands of the rope won't clamp too well to the C-Clamp in being sufficient to pull it. Next we add a soup can around the wire. This metal surround around the say 3/4" rope better clamps down on the rope, but does not really encase the rope well. Next we find a 3/4" ID can or tube to fit around the wire, but it's really thin thus cut thru easily. Given this we add something to gap between the rope encasing ferrule and the screw down clamp in adding thickness and resistance to this twisting clamping pressure.


Given these details, why does wire in plugs once they failed, often seem like the person that tightened the plug did not ensure the terminal was tight? In addition to the skin effect of current flow, remember expansion and contraction also. Might be someone was using a cordless drill or cordless screw driver to tighten the screw terminals without verifying tension by hand. Such tools reduces torque on the screw with each use due to less voltage given off by the battery no matter the clutch setting - always verify the tension by hand. Many times a clutch set cordless tool will click off but the terminal will still be loose. Beyond this and important no matter if by hand or by tool is another key factor - expansion and contraction. This especially the case both when over clamped and when used without ferrules. The conductor in explained above will get hot by way of resistance. Hot metals expand. While they expand they tend to re-settle the stacking on individual conductors in pushing them out of the way. Once those conductors expanded that were pushed out of the way of other conductors that expanded more, when cool, they tend to make for a loose connection. Re-use this connection and it’s now high resistance no matter the installation torque. This especially the case when you put bare wires into a terminal without the benefit of a ferrule to keep the wires together. Some of them conductors will be cut, some clamped so they are solid with other conductors, some short of this ferrule band will just be frayed and loose conductors.

While you do tend to want a tension device applied to wire to be sufficiently tight not to come loose, you don’t want to over tighten them or be under tight given your theory of what’s tight is different than the standard. This is also why specific torque tensions is specified on most plug instruction sheets. Something like 20 PSI for a 60 amp stage pin plug as opposed to 120 PSF for a CamLoc terminal. Given most of don’t have torque screw drivers or wrenches to be used, we and the industry in general relies upon the 1/4 turn past finger tight method in general. Given this base of finger tight is something you have to verify against a known source - someone that by way of their own training has also been verified to have the right tension. Short of this it is torque wrenches in verifying your tension or feel for what’s what PSI in tension.

Given all of this, the plug in question had a factory installed crimp pin instead of a screw terminal. More specifically, the company that manufactured the plugs onto the cable for me were using a four pin indent tool onto a plug using a smaller sized pin cavity specifically designed for the size of a 12ga wire to fit into it. This four pin indent tool costing big bucks, not only accurately crimps the terminal with the accuracy you might expect of a expensive tool, but also in crimping the wire by way of all four sides to it tends to crimp down onto the wire very benevolent to it’s skin effect. Unless the dial for wire size on the crimp tool was set for the wrong gauge of wire - up or down from 12 AWG, there is little to no chance the specific plug in question had other than the proper and low resistance crimp applied to the wire attached to it. We can thus assume in seeing a crimped terminal done by a pro company that it is the proper pressure on the wire on this plug and that it was done properly until proven otherwise.

Such crimp terminals on the stage pin plug is an alternative to the set screw and ferrule method more normal to similar plugs given you need specialized gear to crimp such things.

Hope this info gives out more info on the question and gives out more hints about the options for what went wrong, much less in general how such electricity flows down a wire. Such areas that get hot are hot indeed either by arching or just resistance in general. This heat is dissipated outward from the source of the heat. As a overt hint, this might be a key factor in tracking down the source for the heat, or as soundman says, “I would chop off the broken end and bad wire and just make a new one as long as the wire is up to standard.” Perhaps you might have found a key test as to one of the causes of the failure in better stating an observation as to what went wrong. Now it’s a question of if you note what you than would be studying and crossing out what things could not be the cause of the problem. Thus my also note of being on the cusp of the problem or rational for it's cause.


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## Mayhem

Here are the pics:


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## ship

Mayhem my buddie from down under that also talks funny, he is my bud. 

In any case, as mentioned later in me noting it, this also melted neutral conductor but not the ground conductor noted later when taking photos disturbs and throws off all the simple three causes left for even me based upon only a hot conductor melting. 


There is a fourth and fith perhaps option now that even I have not figured out for sure given this now. For even me, the like melted neutral adds a new factor that even I can't at this point explain as one of three factors.


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## Peter

wow, that was defanatly a ship post!  

I still dont think I understand the entire situation well enough to have any kind of idea what is going on (not that it's ship's fault, I am much more of a show me it, let me feel it, kind of guy). I am probably restating ship's hints, but what I can gather is that there has probably been arcing between some parts of the plug. Could this have been arcing between the ground pin and the hot pin that is damaged? (I seem to remember something from way back that the ground pin was one of the pins with damage) If the plug was dropped, or jammed the wrong way, it seems to me that the pins and wireing inside could be jostled enough, that if some small arcing had melted abit of the insulation already, arcing between two of the pins could have taken place. Again, I really have no idea if I am on the right path here or not, but hey, I might as well share what I am thinking!

Ship, you left me with another question after reading your last post (well, probably several, but I'll just ask one for now b/c it's on the top of my head) what is a ferrule? Maybe it's something I know, but just dont know the real name for, or maybe I am not familar with it. Could someone discribe it or post a pic? Thanks!


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## Peter

Looking at the pics now, It looks to me like when the pin got pushed in, the wire could have gotten all scrunched up and moved alot closer to the other pins, allowing for arcing like i hinted at in my previous post. Just a thought!


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## ship

A ferrule is a nickel plated copper surround for the wire that is sized to the wire size in encapsulating it and providing a cyllinder of metal between it and the individual conductors beneath it and the screw terminal twisting into individual conductors.

McMaster Carr or Allied Elecronics in using the key word ferrule might provode the best results in a cadd cam picture of such a thing. In McMastercarr.com look say for part number 9681k22 for an insulated version of it I most use with a 12ga of the same length sleeve over it for lighting fixture wiring. You gonna like McMaster Carr as a supplier over time this given freqent double orders to them on a busy work day for me such as today in getting parts. First order this morning arrived before 3PM direct delivery, second order in having faxed to them after noon will come UPS by 12 PM the next day. Gotta love for me while I have it at lest same day delivery and most frequent stuff in stock thus no matter the sales adds by other vendors, or how much cheaper at times, just ensuring that you get the product is worth the extra price.


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## soundman

I think a have the next question lined up after this one. 

At least I have gained knowlege at a box of swag but twice as helpful. Do you know the anwser for sure or is this a mystery?


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## Mayhem

Ship said:


> Mayhem my buddie from down under that also talks funny, he is my bud.



What did I do this time buddy


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## JahJahwarrior

ok....now i know what this stag pin looks like! still no new thoughts, and now new ideas for old ones. Let me think this over some more tomorrow....


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## ship

Mayhem should be able to confirm that I have narrowed it down to a chicken or the egg cause of the problem amongst two of five causes I already have not crossed out. Given this, there is still one key feature to this narrowing down.

While still waiting for the mailing address of the last in my opinion fist to get the clue winner of Mayhem's post, this one is still open for a second question winner in getting those third, fourth and fith causes right. Much less in figuring out the rational for crossing out the first and second causes of it.


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## JahJahwarrior

Well, looking at the picture, I am wondering why the cable only dryrotted the insulation and oxidyzed the wiring INSIDE the plug. The heat must not have beenoutside the plug, it must have gotten much hotter inside the plug than outside, ,because there appears to be no damage to the cable otuside the plug. This to me seems to point to something wrong inside the plug itself....which might sound really stupid or simple, but to me that narrows down problems in the other ends. the problem must have just been in this end of the cable.


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## JahJahwarrior

So this is one cause: a problem in the device it was plugged into, causing overheating of the pins, and pushing on pin in. Ship, do you want a more specific explanation of the problem in the other device? or is this one of your causes, and now we only have ilke 4 more to solve??


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## ship

I'm liking this simple study. Who ever "guest" is he or she knows their trade. Don't know where my last post on the plug ended up but I'm sure it ended up in the same section in saying about what guest said. Welcome, come join us as there is lots of need in help or at least clueing things out.

Sorry the plug is now dumpster fill in the end, and by now by way of confirming much of what's observed, we simply cut it, looked for bad wiring at the subsiquent cut and did not find any thus installed a new plug on it. Actually we did not but did observe this cut end in specifically saying that one test that can cross out one of the potential problems. These problems we in cutting might be looking at is if the wire outside of the plug were also destroyed in showing a conductor within the cable itself that overheated by way of overloading. Confusing perhaps, let's lay it out more simple. When the plug was cut off, that area behind the plug looked to be in normal condition. We just did not install a new plug on it as this cable/adaptor has been turned into used resale stock.

In such a cable when overloaded, it's going to fail at the point of most resistance - the plug, but given the overload will also most likely fail between the plug and the cable and the molded splicing point. Given in that cable you did not see any melting as even the plug kind of showed towards the end of the wire also stopped it's melt down as seen by corroded and insulation flaked off wire, we than by cutting the cable confirm that the cause or main purpose of the heat was not by way of loading over it's capacity, more something else. We thus cross out a shorted or semi-shorted fixture attached to it in causing a higher amperage load, or overloading of the assembly in general as the cause. Wire that's not rated for an overload did not burn up while not an absolute reason due to the higher resistance connection is not 100% ruled out, in most cases anyway, this wire will have also burned up given an overloading thus my first test as to the cause and ruling out of at least one cause of the failure. (Long run on sentence.) 

Instead given the problems of a threefer in ensuring it's loading, we took it out of the inventory even if by observation was not the cause of the problem. So now, and given the area of the plug was not the problem, what caused the problem? Chicken or the egg as a hint to this broken pin.


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## JahJahwarrior

So Ship, the hint you gave, ,you are saying, "did the broken pin cause the problem, or did the problme cause the broken pin?" 

I am not sure. Would a bad connection with one pin cause arc welding and the wires to oxydize and dryrot the insulation? I don't know. That would be the broken pin causing the problem. Now, if someone pulls out a threefer to use, and notes a broken pin, they should not have used it at all. My guess is either the pin was broken while they were hooking up electrics, or the person was using the last threefer, and did not see that he would have time to get another, ,and he wnated to go ahead and use it. I think the problem caused the broken pin too. 

One question about the pins: was the pin able to slide in and out? if i pushed on it, would it slide in further? was it possible the pin was pushed in even furhter, but got pulled back out more later, upon removal? How are the pin held in, sot hey don't move??


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## ship

Don't know about your questions, think you are getting to getting to the root of the options, now what specifically caused the occourance? You call yourself a sound guy? My what this says about the lighting guys about the future of them. Hope they at least are following in this study.

Think science however. What beyond pyro can as a red herring force a pin to go backwards while it's pulled from a plug? Given this answer in getting back to the what burned up or was noticed to, what if the plug were dropped after the show when this area that holds the pin in place while not melted became brittle? All in dropping it would than take is the right angle of drop. Always consider Murphy's Law when dealing with gear.

Than again, also remember this pushed in pin and my reference to "The Princess and the pea" fairy tale. Could there have been a pea of some sort or a shorted melting in the slot of the shorted female connector this threeway was plugged into? We are now also taking a large leep off the simple of the description of a source that's supported by a photo. Think facts not photo or what you are provided with. Could some over ambitios gorilla (no doubt IA) stage hand have forced the thing together anyway in breaking the male pin or seeing a already broken pin and using it anyway? Given that the male pin in question and as hinted at, in having it's gap in the pin's slot forced together have caused a high heat by way of resistance connection to the connector given it's now cone shape that's also reduced in length of contact? Consider this cone shape to the pin once both shorer and cone shaped in two dimensions. Will this sort of connection been enough resistance to cause this amount of damage? 

Was the break in the pin, the chicken or the egg even beyond heating by the cone shaped pin? What caused the neutral to also melt down given this? You now enter the world of the something unknown by the "ship."

Doing well on these questions you ask. Not just you but all posters in these questions and interest - what about three of you now in finding out and not looking for the easy answer. just not speaking with seen it before and more the know what happened and asking of it to confirm the last four or five parts of the solution. Chicken or the egg... Hopefully in thinking and solving your way thru a problem in this case study however you will also think thru analyzing other problems as the point however.

Know what could have gone wrong, and as if the scientific theory, test what you can easily to cross out those that cannot be the solution. Than speculate and consider since testing would be a bad thing.

Another hint, look at the photo again now. While I don't have the anser at this point which of the final two it would seem was the actual cause and given it's outside of the plug this cause I either would not see it's cause if fixed in the field or won't for some weeks now at that time I start fixing other jumpers, it's seemingly not in this plug, the wire coming off it, but instead somewhere between the pin and what it was connected to failing I at least surmise.

Now throwing off all of this or helping one or the other thus "the chicken or the egg" I keep stating, what new evidence I had not noted before caused the neutral conductor's insulation to also break down? Note it did not dry rot, that's while almost similar not the same in condition or after effect. This by term was heat damage.


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## Peter

I have one other idea, and maybe it's way out in left field and may have been hinted at before, but is there a chance that a piece of metal crossed the pins or came close to crossing the pins on the outside of the plug in the small gap between the male and female plugs? This, no doubt would not have been helped by any of other things going on with this pin (being pushed in and bent etc...). This idea would probably fall under the "external" sources option left on the list. A close inspection of the external parts of the pins might reveal if arcing or something similar took place on the outside or not. 

One other thing that has just come to me as a possible solution would be what if the pin was not streight inline with the female plug? the pressure from that might push the end pin in, while leaving the other pins without good contact with the female plug, which could cause heat... Just another idea, (or probably more accuratly: semi-educated guess)


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## ship

ah' Peter you are back in the running. 

Don't know. While I doubt it's some form of metal falling across the pins, your other statements are catching up with the quandry. Now what caused the neutral also to melt down?

This as my own question, in pins pushed in and heat on that which had such, yep, you are right on subject of a potintial cause of it.


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## JahJahwarrior

well, I would not think the reduced surface area to be of THAT much consequence. Think of the surface area of an edison plug--much smaller! now, the pin being pushed in shouldn't have made that big of a difference, I think. Unless of course you were running alot more voltage/amps or watts throught the cabling...this is standard 120 volt AC, right? or it is 240? how many amps is the cabling rated for? but see, if you were running too much through it, why didn't the rest of the cable melt? 

or, looking ati it form the other angle, it heated up and made the plastic brittle. Great, someone drops it, knocks the pin in. You could test for this by dropping the pin again, but trying to knock in other pins. If the neutral does get knocked in, then we know that the broken pin came alter. The problem with this is we do not konw how high the cable could have been dropped from. If it was dropped from the grid, that's easily 20 feet, maybe more. And, would that same drop break a normal stage pin? to test that you have to try it out, and you could ruin a perfecty good stage pin, and that's probably not worthit. 

why did it affeect the neutral too? I really get all turned around with electrical workings, ,but doesn't the hot and neutral change directions everh 1/60th of the second? So, anything affecting one plug would also affect the other, right? like....if something was screwingup the hot pin, couldn't it also cause the neutral to heat up? 

I don't see the pin breaking and allt hat from the plug hanging, like, plugging it in to something that fell, or was hanging...if that happened, then all the pins would be bent, right? and that doesn't explain the extreme heat that caused all this havoc. 

So this threefer, it's a 1 male to three female, right? none of the female ends were damaged? so this problem does apppear localied...th eheat much have been created near this end/the resistance much have only occured on this end, or else the cable would have been dmaged. now, the calb ehas more air flwoing by it than the inside of the plug, so it could have escaped visible damage, but then on the other ends, those shuld have had the same thing in them, the insulation burned off, the wire oxydized. I keep coming back in my mind to the oxdyzed wire. why did it oxydize?? 

sleep, then school. g'night!


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## ship

smile on my face as you think too much in needing to re-read the info given.


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## Peter

Ship, By "neutral" you mean the middle pin right, the other two are "hot" with one being postive and one being negative (and them switching between the two very quickly)? 

If that is the case, I would guess that arcing could have taken place between eather, or both of the "hot" pins and the ground pin. This would heat the ground pin. Ah, enlightenment, could the ground plug on the female cable this was pluged into be dammaged, causing a short that was traveling down the ground pin to jump to one or both of the "hot" pins when it reached this point at which it could not go any farther?? This could have heated the plastic and caused it to be brittle and the pins move in and all that type of dammage, which itself couldnt have helped anything. hmm....


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## ship

I think you are thinking too much. First, the neutral is http://www.stagepin.com/20A/adi_-_bates_20a_products.html on the right and right next to the ground pin. The middle pin is the ground pin.

In AC power, we don't refer to a positive or negative because of that reversing directions. Nor are on a 120v circuit there two hot wires even if both of them momentarily carry current in going to and from the power company to the stake (I dread saying this) in the ground at the meter than back again. We say hot because the hot wire coming in has power potential in it. The neutral does not when disconnected from the hot. Or hopefully does not. One might say the hot is the power coming into the building, the ground allows that power to flow.

At the main service panel the ground and neutral are joined together and run to this ground in the ground. Before this point, there is a lot of difference between the two. First, a ground wire while it will work as a neutral during a short to safely conduct electricity as a path of least resistance back to the ground. Such a equipment ground is also attached to every piece of metal between here and there including the lighting pipe thus it’s possible that anything that’s touched that is metal in the whole system if it offers less resistance than the grounding rod attachment will become hot in looking for that neutral return to grounding path.

Now the neutral while it is a form of ground, runs directly to the main power distribution point and does not touch equipment frames, boxes or conduit before it gets there. In doing this, it’s much more safe because it’s not touching anything while not hot in voltage, it still kind of conducts or provides a pathway for the hot to do it’s work. The rest is a little more difficult to explain, ask for a book on basic electricity for Christmas. 

Specifically, the ground center pin showed no abuse. The neutral which normally does not carry any current heated up because it was some form of high resistance pathway for the current to travel to ground while making a circuit. The hot also heated up because it had some form of resistance to current flow. Possibly if used without the plug fully plugged in. Plugged in just enough so there was no shorting at the tip of the pin, not enough of it’s surface area to conduct the current without a sort of funnel back log effect of current wishing to pass thru the joint but not being large enough in surface area to do so. This resistance to the easy path of current flow thus heated up both pins. This probably will have melted the tip of the female plug and not much more than that.

The other option is that in the female connector not shown, that there was some form of high resistance short between neutral and hot. Not a short large enough to trip a circuit breaker or arc, but enough current flow to heat up the pins due to the short between hot and neutral. Water for instance is not the most excellent pathway to conduct electricity. While it’s less resistant to current flow than most metals, it is more conductive than say plastic. Now add a little table salt to the water and it conducts much better. Given this, perhaps the short could have been a wet connector or one in a highly humid atmosphere in jumping the current between hot and neutral. 

Possible, depends upon what the liquid was if it’s only a few drips of water, perhaps it shorted just long enough to arc the pins but also vaporized in the process of doing so thus the amount of time there was a short was not long enough to melt thru. 

Perhaps the strain relief on the female conductor was too tight. This than would force insulation around the wire to be forced out of place. This insulated wire than perhaps allowed some current to bleed thru. All kinds of possibilities for a high resistance short. See the first solution above. In such a condition, not enough to arc the sources due to the resistance still offered by the insulation, but enough to heat up the conductors. Perhaps it was a full fledge arc in heating up hot and neutral but perhaps like a broken filament in a lamp, once it was done heating up the neutral or hot, and the distance between them became too far apart to maintain the arc, it lost conductivity. 

Could be in the female connector, it was arcing in jumping a small gap between conductors but did not have enough amperage to maintain the shorting see the above drop of water or high humidity concept. Perhaps every time the connector was bumped, it momentarily shorted. This arcing and breaking contact over a period of time could also heat up the hot and neutral pins.

Lots of things that can be the case of a high resistance or temporary short. Could also have tripped the breaker, don’t know, was not on the show. Given a short in the female, the male end on the threefer could have been attempted to use on the new cable at which time the male pin broke. Could just be that the threefer with the broken pin was dropped after being replaced because of the short.

One thing is fairly certain, given the neutral wire also suffered from melt down, the squeezed slot in the hot pin, and it’s being broken will have had nothing to do with the neutral also melting down. For this reason, the breaking of the male pin is probably something that happened after the hot and neutral pins and conductors heated up. It being broken is bad but not related to what caused the melt down. In other words, there was more than one thing wrong here and they are only circumstantially related.


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## JahJahwarrior

well dang ship, it sounds ilke you wrote out the possibilities for us in that last post! Or is there more we can figure out, that we need to kepe thinking about? I'm starint to get lost in all this.....


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## techieman33

well this is just me, but couldn't you start a new thread with each new question, it's getting very confusing.


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## ship

Just catching Peter up with you. Don't know about you but in spelling it out again, I think I gave a little more info.

New question will be posted later this weekend. Much more simple. Or is it?


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## Peter

lol, Thanks ship!! I often find myself in that position (having to catch up) but it feels good to have a better understanding of what is going on, and I think that is the whole point here!

I dont know if this is what your getting at, but it seems to me like you are leaning towards it being something wrong with the female plug; something where the hot and neutral (not as i now know, to be confused with the ground, in AC) were able to short circut with eachother at least partially, causing heat to both pins which caused the damage discribed. Further damage was probably later inflicted on this cable at a later time, (when the pin was bent/shoved in).

I dont think this post gets the prize, but I am just going at it again, restating ship's posts!


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## Radman

I'm taking a whack at this way too late but I didn't look into the thread so I don't know the answer yet...

Since the wires are solide they put strain on the terminals of the lamp, and since they are not properly insulated the insulation can melt ant there is a fire hazard and a shock hazard all wrapped into one PAR can of doom!
DOOM!
Doom!
doom!
doom.

Also...

The wires in being solid instead of stranded and not fiberglass or teflon insulated do not comply with NEC regulations:
Article 520.68 (A) (3)


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## Radman

Ooh I hit some if it dead on! Or close enough.


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## Peter

??? What do you mean Radman with your last post? Do you know something we dont know? hmmm.... I guess i am asumeing he hit on the regulation that was being broken that ship wanted to know.... Good Job Radman!!


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## JahJahwarrior

Actualy, radman was posting about the Par 56. hey, is that really in some book, that rule? man...if you are actually quoting some rule there, mad props to you man!! 

Yes, it seems to me that Ship is suggesting exactly waht you said, peter. The only other possibility i see right now is that somehow the plugs were pulled apart alot, leading to high resistence between the two, causing the heat. 

There aren't many explanations that i see for the conductor between the hot and neutral of the female plug either....we have mentioned water of some sort, ,possibility it rained on the plug, and the condensatoin inside allowed electricity to g between the plugs. I think it improbable that there was a wire between the pins, but the plug might have been broken, one side of the cover might have been off, allowig something metal to occasionally connect the two pins. Actually, I am wondering if the cable might have been sliced, letting two sliced wires, ,the hot and neutral, make contact sometimes.


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## Peter

hmm... I just spent a few minutes looking arround online seeing if there was anyway I could check what if anything NEC regulations: Article 520.68 (A) (3) is. No luck though. Radman, if you are seriously quoteing that.... WOW lol, if not, hey, you'll have given us all a laugh!

I agree with you jajahwarrior. Now where's ship to tell us yes, or to add more confusion to this!


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## ship

As Brian reaches for his copy of NEC2000 Handbook and thumbs pages past the drawing in 520.1 of an acceptable two-fer ...

520.68 (A)(3)
“High Temperature Applications. A special Assembly of conductors in sleeving not longer than 1.9m (3.3ft) shall be permitted to be employed in lieu of flexible cord if the individual wires are stranded and rated not less than 125°C (257°F) and the outer sleeve is glass fiber with a wall thickness of at least 0.635mm (0.025 in.).
Portable stage equipment requiring flexible supply conductors with a higher temperature rating where one is permanently attached to the equipment shall be permitted to employ alternate, suitable conductors as determined by a qualified testing laboratory and recognized test standards.” 
(“The requirements of 520.68 (A)(3) cover the connection of high-temperature equipment including stage lighting fixtures, which often do operate at elevated temperatures. High-temperature (150°C to 250°C) extra-hard-usage cords are, in general, not available. Less than extra-hard usage cords are, in general, not available. Less than extra-hard usage cords are limited to 3.3 ft in length to reduce the likelihood that they could be placed on the floor or other area where they might be damaged by traffic or moving scenery.”)


You won’t find a copy on line unless you join. Thinking I’m going to be joining this year, it’s only $130.00 and I’ll get to vote in changes to the 2008 Code, plus as a member have a title under my name something like Member of the NFPA than also be able to use the graphics they send me. Don’t know where they got my name from but about every year of so I get sent an application. Last time my application got lost in red tape of attempting to have the company pay for the membership I would be representing for them. Don’t know if they offer student memberships but once a member you get discounts on the books and news letters. 

Another option might be to get the school to buy one, or shame the principal or who ever controls the purse strings into getting you a copy when you are doing them a big favor. That’s how I got my copy of the Chicago Building code which was not cheap either. Shamed one of our board of directors into buying me a copy so we could become more compliant as a theater, while I was also doing a show for him which I will have done anyway without pay. At very least, perhaps the school library can purchase a copy.

For now, while very expensive, buy the 2005 Handbook version - it’s worth it. Or perhaps you will be able to find a 2002 version at a cut rate, than just buy the 2005 code changes book to supplement it at a more reasonable cost. 

Reason I say this specific book is because in addition to a lot of dry language, the handbook version goes into explaining and expanding on the rules in addition to showing diagrams and photos. In other words, 1,160 pages in a 8.1/2x11" book. This is a good investment and as long as you buy one handbook version, all you will need is the change book every three years afterwards. 

There is many forms of the NEC on the market and by quite a few publishers all taking liberties in what parts they cut out to conserve space. Especially in the guidebook or Illistrated Guide books, they cut out and cut down on a lot of the specialized sections such as theater that are not needed for a more broad sense of it most trades people would be interested in. 

The normal version of the NEC if by the NFPA as a publisher, otherwise is very dry in reading thus in getting board, you tend to gloss over things when they go over your head. This Handbook copy with it’s pictures and descriptions makes it easy to understand. In other words, do not buy the Illustrated or normal Guidebooks to the NEC if you want to look at theater applications of the Code.


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## ship

Now as for Radman’s whack at it, in general he is correct. In general.

Wires that are solid don’t put any more of a strain on a lamp than stranded ones. In fact, since solid wires in this theoretical sense kind of support themselves, they would probably put less weight or pulling pressure depending upon his meaning "straign on the lamp." Same thing with if the idea of putting strain on the lamp is in a solid wire being worse for connectivity to the lamp than a stranded one in putting strain on it. The solid would probably put less of a strain on the lamp because it retains it’s shape. One might find solid wire used in flash lights for instance. 

The rest of the sentence is basically correct in essence - the wire being solid would most likely not be available with a heat rated jacket on it in the proper wire gauge. Thus in being the wrong insulation, pose a fire hazzard though I doubt that the insulation would catch on fire. The shock hazzard on the other hand should the insulation melt off is correct. Is this not the case often with normal PAR cans however? That's why Kupo is selling lamp adjustment knobs and their testing lab otherwise requires a screened cap over the hole in the rear of the fixture. I find this interesting as nobody else has to have this cap to get listed by a testing facility such as UL, but I certainly understand the necessity of it even if it does not allow for adjustment of the beam.


By the way, that fiberglass sleeved conductors is as opposed to other mulit-conductor types of cable that is rated for the temperature such as Rockbestos that would also be acceptable. Also the use of fiberglass sleeving would not exclude the use of properly heat rated conductors; it is in addition to the requirement of them and only a sleeve not a type of wire. 
Some conductors such as TGGT and SF-2 will come with a fiberglass sleeving over the individual conductors which might be argued that such wire does not require the extra over sleeve of 0.025" thick fiberglass sleeve; but it would be incorrect unless the conductor fiberglass over coating were of the same thickness. 
In general, these heat wires come in Teflon and Silicone insulation and both with and without the braided fiberglass over it depending upon the style. This has no overall effect on it’s temperature rating as silicone coated SF-2 with and without the braiding is rated for the same temperature. I prefer fiberglass sleeved SF-2 wire because after the silicone melts, at least you still have what's left of the fiberglass coating on it protecting you, but it still melts just as easily as non-coated ones in similar applications.


Now as for the NEC requirements cited, 520.68 talks about the fixture cord as a supplement to Article #406 which is the fixture cord compliance for more normal fixtures such as the ones Mayhem is using because they are probably not listed for use on the stage. This is a rock and roll aluminum PAR can which arguably given Article 520.68(A)(3) would be non-Code compliant because of it’s thermoplastic SJT cord normally in use that does not comply with the above. 

Rock and roll PAR cans instead are built around Article 406 and 410 for compliance given the differing classification of use for them. In other words, it can be argued that if your par Can has a SJT wire on it such as most rock and roll store bought cans will, it cannot be listed for use on stage. Remember that compliance for rock and roll falls under the more broad "Places of Assembly" classification which allows things like the use of SJ wire when supported by the truss instead of the normal hard service cords.

Given most of them probably are listed for stage and studio use, the testing lab must have written off on the use of that type of cord, or it was an overcite given this rule. This rule also has applications in saying why fiberglass sleeved wires cannot be used for a twofer in additon to the rules against using a plug for an interconnection device or the theater specific rules on twofers being molded and extra hard service in construction.


I'm now off my point...
In any case, Article 520.68(A)(3) does not mention at all the connection to the lamp base, socket as it’s called or lamp itself. It is only talking about the fixture whip which was not shown in the photo thus cannot be commented upon. In other words, in not mentioning the means of attachment of a lamp to the fixture cord, it’s going to be covered in Article 410 - Luminaries (Lighting Fixtures), Lampholders and Lamps as a general covering all theater and other lights with very few exceptions such as arc lights must comply with no matter the application. 

Let’s see, Article 410.3 Live Parts, this photo does comply with in that Mayhem was the one that removed the shrink tubing thus before he removed it, the fixture was in compliance with this.

Article 410.17 also does not matter in that we are not talking about the ground also not the subject of the photo.

What we are looking for is section VI. Wiring of Luminaries (Fixtures)
Article 410.22 and 410.24 would be the ones Radman is looking for where the question of compliance with heat is involved. It also says to see article 402 for types of suitable wire for the wattage or heat of the fixture.

Those of you looking for the rule on the “positive and negative” or hot and neutral will want #410.23 and #410.42(A) which says the same thing.

Stranded wire is 410.28(E), one might also look at (D) which sends us to Article 110.14 for the suitable means of making a splice or tap.

One will note that means of attachment of the lamp to the conductor is not mentioned for other than screw based lamp types in a general look at the NEC. It's probably in 110.14. In general this lack of lamp base on a fixture much less lamp type designed to work with one was the first thing I saw. In not mentioning a lack of lamp base as the first and most important thing, any number of things talked about such as heat wire, solid verses stranded, lack of solder or crimp splice etc. are moot.


There is also that stickler cover-all rule about “done in a professional workmen like manner” which while the wiring was neat, was not professional or what any workmen that did this type of a thing for a living would be caught doing.


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## JahJahwarrior

ok...great...but what about tht threefer? wasn't the whole last post about the par? 

Ship, I didn't bother to read very well that entire last post, but I am wondering, I have a par 64 at my youth gruop and the wiring onthe side is completely burned through, melted, ,dead. like, the wire itself i think was burned through, or oxydized to the point of brekaing. To fix it, what do i need to do? I wsa thiking just replace the wire, but now that you point out all these rules...1) where can I get the wire 2) do i need to replace the entire ceramic lug, which would have the leads on it? 3) is it worth it ?


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## ship

What is this, now I have to play catch up with you or do you block out Peter's messages? The Threefer is already about as figured out as it's going to get.

As for wiring on a PAR can, look for it in a new post under the lighting area section later tonight.


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## JahJahwarrior

well, that is what I was thinking  thanks Ship!


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## Peter

Wow, Ship and Radman, that was impressive! I would have difficulty quoting any source like that! let alone a technical reference! Kudos to both of you! And thanks for all the info! 

I must claim that I was at an unfair advantage for this question b/c I have hardly ever heard of the NEC regulations before this thread, let alone read (or even seen for that matter  ) the regulation book! lol 

I'll have to look into that book, (but like everything else I do, it comes down to $$  ) Be sure it is up at the top of my list of books to buy, especially if I start leaning more and more towards doing this kind of things for a living. A quick question, does this book cover all kinds of electricial wireing type stuff, or more just theatrical stuff? 

To do what seems to be my thing now; Basicly what ship's answer to the orignal question is saying is, the wrong kind of wire was used, and it was not properly attached. The wire was not rated to cary the wattage and handle the heat used/produced by this bulb. 

Have we actually come to some kind of conclusion to this thread?!?! wow! I dont know what I am going to do without this thread! (Looking at other new threads though... it looks like a new thread has been started!! yay!!)


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## ship

The NEC is the National Electrical Code which is while US based, sort of the intronational guidelines for all types of electrical wiring. It comes from the fire department aka the NFPA National Fire Protection Association that beyond the electrical code has say in a few other applications around construction but this is the most well known.

Their purpose for these "guidelines" is in preventing the fires associated with early application of electricity to buildings as it was much more dangerous than gas lighting.

The NEC while not law, is normally adopted in whole with only slight changes by your local authority that is charged with making and enforcing code. It thus as a national set of standards, and in general accepted by all localities is for all intensive purposes "the law" were wiring no matter if it's a boat house or nuclear control room.

That said, Croft/Summers, American Electrician's Handbook, and various books on electricity by Audel are very good texts on the subject. Most books on basic wiring will be based off of explaining the NEC guidelines. Just a question of how theater they get as with guidelines of the NEC. Theater books on lighting to a small extent make up for this lack of info in other texts, but short of doing this all the way, you in my opinion would be well serviced by reading all three sets of sources in general. More so, studying them. Get a Electrician's Pocket book for starters. Read it, first as it's cheap than broaden from there, first with a book on theater lighting than perhaps a NEC book etc. Eventually by the time you are getting into "Handbook fo Electric Power Calculations" that's beyond me at this point for need to know, you will have the subject well covered. In theater books, look for books both from today and the early 70's and before in skipping the 80's where wiring is concerned.

Most important, read and absorb what you can. Don't think I ever got past grounding in my cover to cover read of the NEC. After that, when things came up, I read the section but I'm yet to read it cover to cover also beyond skimming thru it. Other books and instruction for the most part has made up for it in stuff I understand well. Get into transformer taps etc. on stuff I don't use and while I might remember something about details, I would not be ready to do so.

Hope it helps. Good start on the other photo III. Good start indeed as a off the cuff hint. Told you it would be easier. Given the expectations, perhaps just a little refinement of what thoughts are provided so far.


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## Mayhem

Well I must say that I am extremely impressed by the progression of this topic and can honestly say it passed my expectations when I first posted the picture.

As Peter has very nicely pointed out - well done to Radman and Ship for taking this common situation and refering it back to the NEC guidelines. A sort of example of theory in practice.

Thanks!!


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