# Homemade Electric on/off box



## TupeloTechie (Jan 14, 2007)

I have know idea what this is called, but a few years ago I was working on a show and the TD made a box out of wood that housed about 4 residential light switches (on the top) and a residential electrical outlet on the back. He had it wired so you could plug a cable in and it would supply power to all 4 switches, we used this to control a couple of florescent blacklights, a strobe, and a disco ball, because we didn't want to dim them. I need to make one of these for an upcoming show, I have built the box and installed all the switches and outlets from memory, but, I can't remember how he wired it. I was wondering if anybody knew how to wire it so I could get switchable power to each outlet from one plug?


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## Footer (Jan 15, 2007)

A firetrap is what I call it. You can not have any type of connections inside a wooden box without being encased in metal, period. I would suggest going out and getting about 4 or so double gang boxes, mounting them on a piece of ply, and then do all the connections inside the junction boxes and running cable with retention clips between the boxes or something along those lines. One of the last theaters I worked in had about 10 AB switches built in wooden boxes next to the dimmers, and the first thing i did there was rip them out. They each had evidence of charred wood, so take that into account. As far as the wiring goes, I assume you want 1 120v in, going into 4 switches, then going to 4 outlets. Its as simple as splitting the hot wire to each switch, then running the switched hots to each outlet, and then split the neutral and grounds and run it to each outlet.


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## TupeloTechie (Jan 15, 2007)

Do you think if I covered all of the inside of the plywood with a thin sheet metal it would work? If knot I'll just go buy some gang boxes, thanks!


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## ship (Jan 15, 2007)

Agreed... (not the tin coated plywood box but the "fire trap") and also, if you don't remember how to wire it, you should not be wiring it. WAY TOO MANY DETAILS, that is beyond the - how it's wired to wiring it safely.

Get supervision with the TD or ME in doing this or a qualified licenced electrician to teach you both how to do it, and how to do it safely for this thing.

If nobody about to help... don't do it or try harder to find someone that knows the NEC and how to do it according to the code / much less safe and normal standards.

Could be that the old TD had it in a plywood box to house the thing, and it's possible, but either it was metal boxes in that box and the box was to make it nice, or it was "old school" you are best off not re-producting. What ever the case, more instruction and especially supervision is required. We all learn somewhere - better now when your interest is high than learning after it catches fire or shocks someone.

... Wiring... dangerous! Remember that - get proper instruction before doing it.


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## Van (Jan 15, 2007)

I think footer explained the wiring perfectly and ship explained the issues. If you didn't understand exactly what footer said then do not attempt this project. Find someone to help or teach you how. Find an electrcian, and ask them to supervise, a lot of guys would be happy to help you out. I can't impress on enough how dangerous improperly wiring even a simple device such as this can be.


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## ship (Jan 15, 2007)

Of these cautions, you will hopefully note that we are not attempting to say that you cannot do this persay, or should not at least be very much involved with doing it, it's only that you should not by way of to what extent we understand the question be doing it in innitial or subsiquent reply questioned which sort of throws up a red flag.

Believe me, we have most all of us including me started doing such things in the industry such as to the extent of your understanding and intended materials. Harsh way to learn and it's intended by all to save you of potential life and safety risks we learned by way of. Been there, done that with the plywood box type stuff. Done in the past, don't do it any longer.

A book called "Old Electrical Wiring" goes into great detail about even applications of the past where wood were thought a sufficient insulator, and it is as long as dry and there is no sparks such as a non-commercial grade switch just might have as a part of it. Use of other than commercial grade switches and receptacles and or plugs on stage is against the NEC. Many applications of outlet boxes (1900) boxes are also against code to use, but can be - note the plywood backing but there is rules to it - it's a support structure to the boxes when painted and installed for temp. use. Lots of details about what you intend. Simple enough but lots of little assumed details to learn one would not otherwise consider. 

Hope it helps more than telling how to do it. Eyes on your project will in this case be much more help than advice on line. Need to see what type of wire you are using, what the length of stripped wire is, what cord and strain relief is in use etc. In theory, there must be overcurrent protection on this "device" and a incicator light that indicates it's of live power... many other details that are either NEC or waver type things but very specific.


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## BillESC (Jan 15, 2007)

Why anyone would build such a device is beyond me.

This is an 8 channel switch panel, the on/off rocker switches are rear lit when on, it is rack mountable and each switch has a corresponding grounded outlet on the back of the panel. All for around $ 25.00


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## soundlight (Jan 15, 2007)

I second BillESC's response, there are a number of pre-built switch packs out there that are going to cost about the same as you trying to build one yourself.

If you end up building it, have an electrician check it for you, and use double, triple, quadruple, whatever gang you need boxes. Just build a box that you can nail the multi-gang box(es) in to. Make sure that everything is properly grounded, and that everything has wall plates.

I built a dimmer box once, with household dimmers, and I used a triple gang box for three dimmers. I had a separate input and output circuit for each. So, unless you're dimming, get something that already exists for your project!

Again, I'm with everyone else - DO NOT USE WOOD AS THE PRIMARY ENCLOSURE - USE WALL BOXES!! This could be a huge fire hazard, and could be a dissaster if not wired properly. If you know an electrician, or if you are in a school system (in which you can contact the school our county electrician), have them check this out for you before and after you finish it! And maybe even help you build it. Mak sure that you do all of your grounding properly.


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## TupeloTechie (Jan 15, 2007)

ok, the reason I am building one is that I have all the materials, (except gang boxes), which I will buy, I know that you all are trying to help me, but I need this very soon, I have read a book about home wiring, and my brother has helped an electrician one summer, so he knows alot about them, but *I was wondering what it the safest way to split the hot and neutral. And the best way to ground this box.
*
Thanks to all who helped, I probably would have blown myself up by now if it wasn't for you.


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## n1ist (Jan 15, 2007)

Judging from your questions, I would also suggest you don't try to build this yourself and use it in a public place. The liability and safety issues are too great. 

You say that you have all of the parts except the box - what kind of power cord are you using? What kind of cable clamps (no romex/mc clamps allowed)? What kind of wire inside the box? How are you grounding the box? What size wire nuts will you use to split the hot wire to the switches? What kind of box do you plan to use (no boxes with knockouts)? If the receptacles mount to the covers, do they mount with more than one screw (code requires that now...)?

I'm not saying that you couldn't do this safely, but you have to be very careful. If you do build this box (or any other electrical project), have someone who really knows electrical code look it over, and don't believe everything you hear at the local home improvement or hardware store; you would be amazed what I have heard there...

To answer your questions, I would use a wire nut to split the incoming hot to the pigtails for each switch (check the box to know if it can handle the 5 14ga wires you plan to use). You can do the same for the incoming neutral or daisy chain it from one recept to the next. Tie all of the grounds together and run a wire to the green screw at the back of the box; you can get ground pigtails with the screw from the hardware store.


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## soundlight (Jan 15, 2007)

I would make sure that all of the wire nuts are hooked up in the gang boxes, and there are only insulated wires inside the box.


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## highschooltech (Jan 17, 2007)

Wow, this has dangerous writen all over it. Short circuits are bad, they spark and start fires if there are flamible things in the area like wood.


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## ship (Jan 18, 2007)

TupeloTechieKid said:


> ok, the reason I am building one is that I have all the materials, (except gang boxes), which I will buy, I know that you all are trying to help me, but I need this very soon, I have read a book about home wiring, and my brother has helped an electrician one summer, so he knows alot about them, but *I was wondering what it the safest way to split the hot and neutral. And the best way to ground this box.
> *
> Thanks to all who helped, I probably would have blown myself up by now if it wasn't for you.



Below is some things to study and sugguestions on materials that often would be used. It is recommended that you do not build this proposed box but for education value or if you are going to do it any way, here is the concepts to look into. Not as simple as just wiring up a bunch of switches and outlets - nor even dimmers to outlets and cord. There is some very specific rules and even a 1900 wall box is frouned upon. Often the slugs from such a box other than in a wall get knocked inward and can short to even an electrical taped live conductor or screw. Wall boxes are not recommended to use for any portable application.

If your brother has had sufficient instruction in this he might be qualified to supervise it, one summer however does not always mean sufficiently trained as an electrician - more trained in hanging the boxes and other rough in work. Could be and possible, kind of depends upon what he was doing and how much training he had. Still it's a good start and hopefully your brother if there is something he is not trained in will have a contact to ask. Stressing the hands on, eyes on the project. 

Like Bill's solution, quick and easy, save the parts and have something really good and UL listed for the price it's going to cost you in follow up parts. 1900 boxes, covers etc, or if that is not expensive enough the cost of removing inventory from your stock that will at some point need replacement. $25.00 is a good price for what it is doing. We are talking about indicator lights to show live circuits - required, UL listed, Overcurrent protection, rack mounted and case grounded. Much less looks nice and professional.

Again with the terminology that sends up red flags: "I was wondering what it the safest way to split the hot and neutral. And the best way to ground this box." Split the hot and neutral... you might know what you mean but such words send up red flags with me thus also the concern that most share. Terms are a part of understanding. Look back at such terms five or ten years from now and you will understand the red flags about the intended project still. If what above means how to tap the hot and neutral conductors to supply multiple switches and outlets or something similar in terminology, if the thing is not portable and temporary in construction, than a properly sized wire nut would be sufficient. If portable, a cap splice is normally preferred as wire nuts have the nasty habit of coming loose. This or sending the power in cables to a Millenium strip for proper distribution. All assuming that before you distribute the power, it's line in to over-current protection such as a circuit breaker or fuse as required. Otherwise what happens if of these switched circuits you pull more than the rated amperage? What wall outlet this is plugged into won't protect against voltage drop of the load right away - read in your electric's book about "sub-panels", this is for all intensive purposes what you are doing here. If more than six switches you will be best with a circuit breaker or need to have a switch to act as a master to kill all switches.

Ok, the neutral must be isolated from the box (for all intensive purposes much of what you are doing is a portable sub-panel even if using switches instead of circuit breakers) - again the wire nut and or millenium bar or isolated neutral bus bar depending upon the application. 

The ground is required to go to the back of the box and be attached to it by way of ground bus or thru the threaded hole in the back of the conduit box. From there if two or less things requiring grounding, you can send a 6" grounding wire up to the device. Otherwise as long as your boxes have box to box connectors and a secure mechanical ground, the second grounding hole can be used in the second box with the 6" tails. Best to use a grounding bar for all grounds but it's a question of how to and box fill. This is not some electrical box installed in a wall but still must comply with "box fill requirements."

The "box fill requirements" will be in the book along with how to do grounding and details about this. 

Gauge of wire... don't use less than 12AWG if you can help it. Unless your over-current protection on the device is specifically 15A and cannot be changed to a higher amperage, it's a bad idea. Cord no longer than three feet and the same wire gauge is optimum. Type MTW conductors be it stranded THHN/MTW or specificially type MTW as different is what is normally used. Solid core wire for portable appications - even if within the box is not done. Cable feeding the contraption should be 12/3 SO if at all possible but 12/3 SJ would be acceptable. If you need a longer extension to feed this thing, do an extension cord.

Each switch and receptacle needs to be commercial grade - remember Bill's above $25.00 box above? Price out the commercial grade switches, much less just one mini-breaker and you just went over budget. The NEC is very specific about not using home owner grade devices in a theater or place of assembly. As a given the above switch box probably won't be using commercial grade receptacles, but it is a UL listed device, your's will not be and needs to comply in all possible ways with the NEC.

Next, you need an indicatator light for each circuit and one for the main power in. This is useful in letting you know what is live and at very least in the box being live a code requirement for a portable distribution box.

By code, electrical boxes are not structural nor are you allowed to be using a line voltage pendant or remote switching device. The conduit boxes need a painted plywood backing if attached together and if at all possible this thing needs mounting to a table and or wall so as to prevent anything bad from happening should it fall over for instance.

That's all preliminary type stuff, again eyes on site will show proper strain reliefs, and lots of other stuff not covered. Also, anything above doesn't even mean that it's accepted by your local code or a inspector just seeing the gear won't tag it for violation of the code because it's a tricky thing what's permissible or not. Beyond all this, get what you create inspected by the supervisor responsible for the theater and have that person sign off on your work. Liability of this box must be with the person on paper responsible for it and all lives assembled within it. 

Highly not recommended to do this project, have your brother look over his copy of the NEC about these concepts expressed, verify the ideas and inspect the gear you currently have to do this project with.


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## PhantomD (Jan 18, 2007)

This thread is going to give me nightmares forever. 

I get an electrician friend of mine to do all that stuff, while I do up his TV stuff and computer. He is unfortunately a crack-shot with audio so I can't help him with that!


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## TupeloTechie (Jan 19, 2007)

hey, just to save people from the nightmares, I was at guitar center the other day and picked up one of those boxes like Bill mentioned, I have no idea what I was thinking, I can't believe I tried to build this!

BUT... THANKS to all those who helped me out, This thread has taught me a lot about electricity!


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## Van (Jan 19, 2007)

TupeloTechieKid said:


> hey, just to save people from the nightmares, I was at guitar center the other day and picked up one of those boxes like Bill mentioned, I have no idea what I was thinking, I can't believe I tried to build this!
> 
> BUT... THANKS to all those who helped me out, This thread has taught me a lot about electricity!


 

Yay ! 
< van let's his breath out finally.>


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## soundlight (Jan 19, 2007)

HURRAH! HURRAH! The end of the world is not now at hand!

Well, it's good to know that you learned a lot about electricity.


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## BillESC (Jan 20, 2007)

GC gets another sale... 

What did it cost you with tax?


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## TupeloTechie (Jan 21, 2007)

BillESC said:


> GC gets another sale...
> What did it cost you with tax?



$32  

If i wasn't in need of it buy the next day...

but then again, I probably would have electrocuted myself If I didn't...


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## ship (Jan 22, 2007)

By the way in what was not caught... "Millenium strip" was incorrect in my terminology, it's "Marithon Block" that would be the proper term for what I was thinking.

None the less, good to see that you bought the component that did what you intended rather than built it which might work but would not work within the intent of safety. 

For me at the moment, I'm working on a 30 Amp three phase to six circuit 20 Amp two phase "Emergency Stop" system "E-Stop" component that powers up a bunch of ribbon lifts for a tour. Three emergency stop button locations to the kill switch power, lots of indicator lights, circuit breakers and a Socapex output that's wired so as not to blow up a 120v output plugged into it in adding to the wiring, 5V remote power to the switches, circuit boards and relay switch difficulties all fitting into a two rack space component.

Beyond that, the production designer wanted this "E-Stop" power to the ribbon hoist/lifts to be universal in 120v and 230v Volt American/Euro wiring. Yea, that's the great concept in wiring these days... stuff that will work here and overseas. Yea.. my circuit breakers would work in eigher voltage as the only question asked.. but given the details it would require total re-wiring and the electronics package would not accept dual voltage without a switchable power supply circuiting. This plus our Socapex wiring unique to the US as the alternative in safe wiring here would throw further a wrench into the works. Did the E-Stop, only for 120v/208v couldn't do it for 120/208 plus 230v short of a lot of extra circuiting. 

Sort of like the switch discussed, much more complex. At times you have to do such things, best to buy them - if it existed, we would have bought it, since it didn't, much less DMX controlled ribbon lifts didn't exist before we made them that became in part my job. 
If not available, there is no replacement for study and experience. In my case, our other ME took a good long look at what I was doing and gave his seal of approval to it also - even I don't hack wire stuff together without getting in someone else to have a look at what I'm doing. Nor does he do stuff I don't look at.

That's our as it were UL listing system given lots of Insurance and experience professionally in doing that sort of thing for a living. Were it not for such a background, aways better to buy what's pre-built or at very least be absolutely certain to all extents available and beyond that possible that you can ask, in what you construct is proper and safe. Cover your rear. Worst that can happen is that you learn something. Best that can happen is that it works as designed and that person you ask starts asking you for advice.


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## SHARYNF (Jan 22, 2007)

Hi Ship
Had you looked at adding a transformer to the input, have multiple inputs b ased on US or EU power, and then keep your outputs constant?
Sharyn


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## ship (Jan 24, 2007)

Not to change the topic but in further discussing or understanding distribution unit design problems and concepts, continuing the topic and further detail of the US/Euro wired E-Stop from last week might be useful. 

Doing US/Euro power supplies is very difficult - where the industry is going but hard to engineer something that’s universal - not as easy as a switchable moving light power supply or just changing the lamps in a fixture. Many companies are working on such gear and soon will have UL listings on it, but most at least power supplies have very difficult problems to overcome first. My big boss’s want’s such gear badly, and TBA more and more, all new gear we make these days as with this project have this “world tour” concept in mind with it. (Means I need to go to school for Euro wiring and code more than I have.) At the shop in buying and building the gear, we are working on this vision, it’s not cheap or easy to get and there is major differences that require huge compromises or changes at this point. Huge problems in getting it universal - at times in debate with what our current power supply engineers specify of what we will get, I can state the NEC until I’m blue in the face in defense of some standard we use or need and the manufacturer of our next generation of AC distro still says no, can’t do it... type stuff. Last I knew, we were getting something at this point, it’s going to be difficult to make full use of.

Onto the current E-Stop problem.

I was doing the electric, the electronics department was doing the electronics and relay specifying and constructing part of it. The person from that department who did the electronics agreed that he could have made his part of it Euro/US, but only - given more R&D pre-production time than less than a week. I could probably also have done some stuff differently.... This granted, already both of us had full schedules of stuff to work on for that production and many other shows, much less had set backs in design. Stuff like "I thought you were buying the Emergency Stop switches" type interdepartmental problems - on the last day which forced us to send it off a day late by mail to catch up with the show. This and given all worked without huge problems, only one lost hour trying to figure out why the remote stops didn't work... something about something forgotten on them which challenged our UPS pickup time. Hmm, remote kill switches that will work as a system no matter how many are plugged in? Just takes some circuitry but an added component.

Anyway, the specified design concept was to have circuit breakers that could handle both 120v and 230v power systems. That was not a problem, most are rated for either 240 or 250v and don't care if a 120v or 230v world - it's about the amperage. Power in was to be the US based L21-30 which is three phase five wire twist lock. No real problem to adapt to it for a Euro plug. Output was to be the alternate/safety config. of 208v Socapex that has it's wiring/phasing set up in such a way that if you plug a 120v output into it, it won't blow up what's plugged into it. Beyond that, there was to be two low voltage remote kill switches that ran off 4-pin XLR cable. This was the specification as planned by the production managers.

Problems came in the reality of the wiring and or my understanding of Euro wiring. It has always been my impression in the past that normal Euro wiring used 230v hot and a neutral. This would tend to be a huge problem with this was wired for the dual 120v hot leg 208v that's fed by three phase power and would not use the neutral leg of power other than for needs by the circuit board and various indicator lights. Ain’t no neutrals in this 208v Socapex plug, how are you going to power it up for 230v six circuit?

Unless I mis-understand Euro wiring for what is in the US, two phase 208v gear, Euro stuff 230v in general would not see two hot legs ?416v, (which when put to him, the specifier of the gear also had to scratch his head and wander off in not knowing for sure - this after yelling about our lack of ability to do specifically as he asked.. Ok, I did exactly as he asked but I should have made it dual input anyway somehow as desired.) Euro gear such as a in this country two phase ribbon lift, would in Europe at least I believe normally see one hot leg at 230v single phase and a neutral thus be a single phase item or would it? I scratch my head also on this - don’t know, didn’t research sufficiently given the one week turn around. Only way to get such power supply - unless Euro is two hot legs/two phase also, would be to totally re-wire, remove wires from breakers and put them into neutral bus bars from a US based system. That’s stuff I don’t fully know yet, nor had time to research in the (new technology) ribbon lifts this was to power up if it’s in wiring for Euro needs, having a hot and neutral or still two phase power. This was a major/huge detail I could not design for thus did not. 

This much less from the wiring standpoint I was doing, doing power in indicator lights would be much more difficult. Short of circuitry to show what phase was missing in going phase to phase indicator lights as opposed to one indicator light hot to neutral per phase. Were I to do phase to phase indicator lights, one would know there is a problem but not know which one had the problem easily. Otherwise in just indicator lights on the power in side, were I to go phase to phase in doing 250v, I would either blow them up once they hit Europe or if I did 250v indicator lights in going hot to neutral, have lights at half their intensity in doing 120v which might not be bright enough. 

No such thing as a over 250v indicator light that I’m aware of, so doing any form of indicator lights on the power in much less power out for two phase six circuit indication just became very difficult. Potentially I could do half bright 250v hot to neutral indicator lights for the power in, but there would be no way of doing a phase to phase two phase individual circuit indicator light short of doubling the 250v lamps now for each phase of power - 12 lamps tied to the neutral instead of just going between the two phases of power. (Could have solved the problem, was not easy or effective for this first attempt.) 

Now anyway in wiring the thing, we were faced in six circuit 208v output with the potential unknown problems of for Euro shows somehow removing the now second hot wire legs tied into the three phases of power and turning them into neutral legs instead. 

IN theory, one could leave the neutrals in the dual two phase breakers - Code requires if switching off the neutral, it’s absolutely switched off at the same time as the hot. It’s just not normally done that way but a dual pole circuit breaker would do so. While not good practice, one could in theory use a dual pole breaker with the neutral running thru it for such an application. (Wonder if it would survive a PATT test this theory by Euro wiring standards?) Now we would just would need some form of say three way multi-pole switch that would switch each second leg phase of power between 120v and neutral. Not aware of such a thing existing but I’m sure it requires circuitry and some form of relay switch - three way 30A three pole relay switch if such a thing exists to switch the second poles of a 208v system between 208v and the neutral leg of a 230v system. Probably would also require some form of safety circuitry to safely do this.

So now in doing a three pole relay switch that's controlled by the circuitry (in this case at 120v), we either have some form of six pole relay switch that treats hot and potentially hot or neutral depending upon the country it's used in differently or have to pre-relay the switchable power imput three pole relay switch with some form of neutral/hot switching threeway relay switch before the E-Stop controlled relay switch. This six pole and or three-way relay switch than would also have to be circuited in with switchable power supplies for the rest of the circuitry, otherwise one might hit one switchable or auto-detect power supply switch or transformer but not a second one. The circuitry in detecting a need to kill the system at 120v or 230v is a seperate componet than that of the component that does the actual switching. Easy enough to splice or wire but more components to add and troubleshoot.

Them’s major problems in my understanding beyond the concept that a L6-15 two phase plug - normally we would use to distribute a 208v Socapex plug to six individual fixtures is rated for 250v. If it’s true that this Socapex plug (if even rated for six circuits of ?416v) is now doing 12 circuits of 230v, the plugs we by design will have been distributing the dual phase 230v load with will at over 400v have been not rated for the voltage. This much less nor would the 12/3 SJOOW cable such a fan-out of power the cables making up the fan out will have been wired with been rated for. 12/3 SJOOW cable is only rated for 300v. Electrically, even if this thing were able to do both US/Euro in going to a Socapex output, nothing existing as normally used in the US or Europe distributes Socapex to 12 hot wire to over 300v six circuit output. No such thing. Intended was to use our 208v wired six circuit fan-outs.. They are rated for 250v at the plug and 300v on the cable. That means we would either have to re-wire the power supply so it’s using neutrals, or figure out some other form of no longer universal way to distribute what power the rack could supply. Not easy to do universal.

Electronically, I assume that 60Hz verses 50Hz will not have been a problem for the circuitry - this and what power it’s fed could be switched thru a transformer. This granted in-line safety fuses and other circuitry to ensure you don’t blow up a circuit board and other relays etc. All will have required a larger rack mount space also than the 6" deep two rack space panel I attempted to use and was challenged to fit all into. This was one of those cases of - yea, I know CU requirements and I added venting to the thing, but didn’t have time to do a larger than off the shelf rack mount housing. Looks good and is safe but the Cubic inches of cooling space within is negotiable given ventilation provided to supplement it.

A month will have been needed to design such a thing for dual Euro/US voltage needs. This in addition to inter department design/production meetings (as if production meetings for a show) on it that’s un-heard of other than for huge projects.

Here is what I at least wired in doing it for a three phase to six circuit two phase Emergency Stop system in the 120v/208v world:

Power in, L12-30P flange mount 120/208v Wye 30 Amp plug. #10 MTW wire to a Square D series QOU 30Amp 3-Pole circuit breaker. Neutral was sent to an isolated four hole neutral bus, and ground to a bus / grounding strip of the same amount of holes by the same gauge and type of wire above, but in this case mounted directly to the panel. Off the main breaker was 120v indicator lights wired off each of the load side of the three poles and in return combined and tied to a neutral wire going to the neutral bus bar. Also, on the X and Y phases, power to a circuit board and to the power relay. Both also had a wire leading to the isolated neutral bus - about the extent I did beyond mounting components in wiring the circuitry. I do relays as needed, in this case, circuitry was another department and I worried about my own.

Circuit board fed the three phase power relay which the main circuit breaker in the same wire was feeding. Circuit board than took it’s instructions from the various by now three (one rack mounted) emergency stop switches that were store bought. Two remote kill switches were remote and fed by way of four pin scroller cable but this switch needed to have the option of not using any or all remote kill switches, and or if there were a problem in wiring, compensate for it in any working irrespective of what another kill switch was thinking - other than if locked into the off position. 4-pin XLR off the rear of the panel mount power supply fed the remote kill switches - this needed to detect if they were plugged in or not in still working. Also out of safety and idiot proofing, it needed to be safe incase someone plugged in a either 4-pin headset system to this emergency stop system, or anything from a scroller to a LED based Color Blast fixture to it. In other words, 4-pin XLR is fairly common in use thus we had to design around it to idiot proof the gear. Used pins 2 & 4 for the remote kill switches, and 1&3 for bridging between them to tell the detection / shorting circuit if something was plugged in or not. (There was some design to this, just not enough time to make it universal.) Given it was only a 5v relay signal, it made it easy on amongst four types of scroller/Color Blast 4-pin XLR cable in stock, we were able to use the never used “Color Fader” type cable which doesn’t have the 14ga wires in it, the cable that’s rarely used and obsolete. That at least is a good thing - just using the cable for a relay signal and not needing the more used cable.

So the power and control is now at a three phase 30Amp relay switch. (The power relay talks to the circuit board somehow that was the electronics department based.) Anyway, #10 MTW wire from there to a three pole four output Marathon block, four circuits three pole of #12 MTW wire out of it going to six two pole 20A magnetic circuit breakers. These are phased and wired as per the “plan B” in the industry alternate method of wiring 208V Socapex so it don’t blow up if you plug a 120v application into it. Circuit breakers go to the Socapex outlet along with six ground wires dual wired into the three terminals of the ground bus. Each output for the six circuit two phase circuit breaker also had a 250v indicator light wired between output on the breaker for the breaker so as to indicate individual power and overall = “it’s been killed power.” I indicated power in (after the main breaker) and power out (after the output breakers.)

Socapex plug leads to a fan-out or as it were Socapex male Veam brand VSC series KK clamp type six circuit 12/3 SJOOW output to L6-15R adaptor. (Industry standard these days is more the L6-20 system but it would cost too much to convert at this point.) Anyway, it’s a Socapex male to six individual cables of 208v power adaptor which than feeds each individual power supply to the hoists. This part of the system, even if it were a switchable power supply would be problem #2 to why it cannot be easily done as per requested design. Nope, no way to do it.

Not a lot of time or room to do other than what we did. Nice clean and working 120v/208v system package. A few errors on my part in labeling the rack than adding stuff, but overall = very easy to understand and safe.

Doing it 120/208v and 230v/?416v? That would require lots more work and time. Can’t be done easily.

Lots of details left out such as crimped ferrules, insulation and isolation of the circuit board etc. Wiring and making power supplies is complex. Add to that the mandate of making it dual voltage and given less than a week with lots of other stuff to be working on... nope... Be easier to make a seperate 230v power supply before the tour gets to Europe than to put everythign else asside within the time limits.


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