# Making extension cords and quad boxes



## Daveslights

Hey,
I'm thinking about making some extension cords (20A 110) and some quad boxes. 

What kind of cable should I get, and where should I get it from?

Are there any 'how to' guides online anywhere? 

What I really want to make is an 20' extension cord with an outlet every 5' or so


----------



## SerraAva

For 20A, you should make the cable out of 12 gauge wire or lower. Here is a chart showing the max amperage for each gauge of wire. Also make sure you use plugs and outlets that are rated for 20+ amps, as most households in America use 15A lines and breakers for most of their outlets. 20 amps are becoming more common however.


----------



## zac850

12/3 SO cable.

Technically, a normal edison plug is only rated for 15 amps, if you want to legally push 20 amps through it, you need the plug with the sideways pin. see here


----------



## SteveB

Daveslights said:


> Hey,
> I'm thinking about making some extension cords (20A 110) and some quad boxes.
> What kind of cable should I get, and where should I get it from?
> Are there any 'how to' guides online anywhere?
> What I really want to make is an 20' extension cord with an outlet every 5' or so



Some thoughts, as I tend to make my own as well.

- Somebody can correct me if this is in error, but I believe the NEC recently disallowed the use of portable outlet boxes on a floor whose outlets face up - I.E. you cannot use a standard 1900 metal box with dual duplex on a cover. You now have to use boxes where the outlets are on the side of the box. I believe this is the reason LEX products recently changed a whole lot of their distribution boxes. 

I happen to love the outlet boxes made by Woodhead - http://www.woodhead.com/products/electrical/portablepower/

They are very pricey, but need little maintenance down the road. FWIW, receptacle boxes made with standard electrical parts - handy boxes, 2 screw strain reliefs, etc... tend to loosen up in short order and need constant attention. Which is why I like the Woodheads, as none of the connections and fittings come loose.

- Cable should be 12/3 SOOW for use on stage. 20 amp rated and it's the code for theatres.

- Connectors might want to be heavy duty rated 15 amp edison (not the cheap crap sold at Home Depot though they can sometimes carry the better quality as well), as the 20 amp version now has the neutral pin at 90 degrees, thus it may not mate to existing gear. This means that you would be building 15 amp rated extension cords and would need to use them on power sources protected at 15 amps. 

- Generally I order from an electrical supply house, as they tend to stock exactly what I need, where as with HD and Lowes it's it and miss as to stock, especially longer lengths (if any lengths) of 12/3.

Steve B.


----------



## SerraAva

Ahhh yes. Forgot about the 90 degree neutral on the 20a edison now. The DP-640Bs I ordered from Elation had them on it. That was an easy enough fix however . 

I have only seen twenty-five 20a outlets with the 90 degree neutral in it, one was at Wyeth's headquarters in Collegeville, PA. Funny thing is that it's a single outlet, yet all the outlets above it are ganged 20's. The other twenty-four, on the DP-640Bs. They can take 90 degree or regular, which when you think about it, defeats the propose of the 90 degree neutral. Nothing stops me from sending 20a down a 15a plug like that.


----------



## soundman

Food for thought only the male end really ends to be a 20A or greater plug. This sounds like something for a low amperage application like music stands or something. Regardless if that is what it is designed for or not making every female plug on the chain 20A will only encourage it to be overloaded.


----------



## len

SteveB said:


> I happen to love the outlet boxes made by Woodhead - http://www.woodhead.com/products/electrical/portablepower/
> They are very pricey, but need little maintenance down the road. FWIW,



Thanks for that. I wonder if they make those in black. Yellow doesn't cut it for the corporate work I do.

Edit: They come in black, also. 

Also, do you really need to be 20 amp capable?


----------



## BillESC

You might consider MOX cable from LEX and CBI.

They are 14 gauge and available in 25' w/3 outlets and 50' w/6 outlets. They are well made and the end female connector has an LED in it to indicate power.

Not much more expensive than buying the parts and doing the assembly.


----------



## SteveB

len said:


> Thanks for that. I wonder if they make those in black. Yellow doesn't cut it for the corporate work I do.
> Edit: They come in black, also.
> Also, do you really need to be 20 amp capable?



No, you can make them in 15 amp, but for use in a theatrical setting, and best check the NEC as to where section 520 applies, I believe 12/3 SO 20 amp cables are the minimum. Even SJ style, light duty jacket, can only be used in overhead (pipes/truss) applications in lengths not exceeding 20 ft. Thus no on-deck usage for SJ. 

As to making them yourself ?. Tough call, given varying costs of labor. I don't like the Lex orchestra extensions, as I find the outlets need to be closer then 8ft. They make a model with 5 outlets at 4'-8", but I have no need for that many receptacles - building my own as 3ft. with duplex and feed-thru, or same at 6ft. Lex doesn't make it that way, but otherwise there stuff is very cost effective. 

The one thing I hate about the new 20 amp Edison with the sideways neutral, is it's seemingly common practice to use a compatible 20 amp receptacle on a circuit protected at 20 amps, yet I constantly see extension cords rated at 15 amps downstream, as the 15 amp male plug readily mates with the 20 amp receptacles. This is a code violation as the over current is rated higher then the cable, making the cable the weak link. I've pointed this out to more then one sound company who builds their own power distro's. They go "Uh ?". 

Steve B.


----------



## avkid

zac850 said:


> 12/3 SO cable.
> Technically, a normal edison plug is only rated for 15 amps, if you want to legally push 20 amps through it, you need the plug with the sideways pin. see here


Eh...Wrong answer.
12/3 SOOW


----------



## gafftaper

BillESC said:


> You might consider MOX cable from LEX and CBI.
> They are 14 gauge and available in 25' w/3 outlets and 50' w/6 outlets. They are well made and the end female connector has an LED in it to indicate power.
> Not much more expensive than buying the parts and doing the assemply.



Yeah Bill I was thinking the same thing. There are premade products out there. By the time you start buying all the parts to do it right, you are going to be up there in cost. I think it's worth checking out Lex and others.


----------



## len

For me, the big advantage to building myself is getting a length I need. I carry a lot of 10', 15' and 20' which are ideal for what I do.

As for the parts, I find SJ 14/3 on ebay for about .5 a foot. Connectors go for about $5 each if you buy in quantity. Obviously, the longer the cord length, the cheaper the finished product is.


----------



## SHARYNF

Problem is 14 3 is undersized for more than a single 15 amp connection, and SJ technically is not allowed for on stage floor use. There are a number of these that show up on Ebay on occasion but they use 16 3 which is really just about useless



Sharyn


----------



## len

Depends on what you're using it for. Mostly, I'll have some led on it, and 250 watt movers. If I'm using a larger mover, or a theatrical fixture, it'll be on a multi-pin cable.


----------



## SHARYNF

Problem is if you put 10 250 watt movers on the string the load would be at 2500 watts and you would need the full 12/3 
Remember the breaker is to protect the cable, so if you can over load the cable before the breaker trips, you run the danger of having problems with an underrated ampacity For the price difference IMO 12/3 Soow is worth the price

Sharyn


----------



## gafftaper

SHARYNF said:


> Problem is if you put 10 250 watt movers on the string the load would be at 2500 watts and you would need the full 12/3
> Remember the breaker is to protect the cable, so if you can over load the cable before the breaker trips, you run the danger of having problems with an underrated ampacity For the price difference IMO 12/3 Soow is worth the price
> Sharyn



It also doesn't cost THAT much more to move up from an SJ to SOOW.


----------



## avkid

gafftaper said:


> It also doesn't cost THAT much more to move up from an SJ to SOOW.


Probably less than the revenue lost when your rig gets red tagged.


----------



## len

SHARYNF said:


> Problem is if you put 10 250 watt movers on the string ...



I can't imagine doing that. At roughly 4 amps or more per fixture, that would be more power than the typical 15 amp circuit could handle. At most I run 2 moving lights on a circuit. Mostly, I'm working in hotel ballrooms and we're not allowed to use the panel without paying a hefty premium for the house electrician to open the electrical panel. And if the client's budget can't handle it we have to work around it. We have to design the rig based on available wall power. A pain, but a reality. So having 12 gauge wire isn't worth the expense.


----------



## ship

For stage usage it is code complaint these days to use a Commercial/Industrial grade 15A Edison plug in place of a 20A Edison plug - the two type are the same in specification and do at times confuse those that would be intended to use them. Once had a “Pro tech person with decades in the industry” re-plug all my 5-20P plugs to 5-15P at the expense of a few hours before a show because he didn’t realize that the 20A recepacles on the rack he was to plug into would accept such a plug properly. For this same plug and standardization in general I believe for stage usage the 20A Edison plug has been waved in need/requirement. The 15A and 20A plugs if of the same grade between 15A and 20A are the exact same plug only with slightly different pin configurations. It is in otherwords acceptable on stage to pull 20A thru a commercial grade 15A Edison plug.

However, as general concept your Quad box with Edison cord feeding it is not code compliant both by way of using 1900 regular construction boxes, indicator lights on the boxes and the overall loading of the cord that could melt down before a circuit breaker could pop given a long length of cable due to voltage drop, resistance by way of connections and taps.

Outlets facing up... (As per Steve B), believe I read the exact same memo in confirming it. This in addition to the general construction grade convience boxes with knock out seals in general being allowed for use on a cord and other than in a wall space. Much less beyond this any multi-outlet receptacle box without indicator light. There are types of boxes that are compliant and Lex is not only on the NEC board for rules but the cutting edge for compliance - should visit their website for more details in what is what. 

Woodhead is a great company especially for twofers.(only brand I buy.) Just bought more of the LEX (non-compliant) orchestra stringers (4'-8" on center I do find use for) and while they were non-code compliant persay for a floor application, they while the industry gets itself up to standard did fulfill my needs. (This until I reform my CamLoc vulconizer into a custom Edison outlet and screw base tapping stringer machine.) You can get various yellow most commonly or black outlet boxes that are cord mountable even in the quad configuration, this is the option that is compliant for the most part though I have issues with strain relief on such things. And I do use such rubberized double and single sided boxes at times.

Problem with such cable companies making outlets is that they don’t easily do custom cable lengths so the making your own does comply to some extent. Also, in doing say an O’Stringer, you only get one outlet per segment and at times you need more than that. What would be more safe at that point, tapping the outlet for more such as with a cube tap or factory installing a quad?

Overall, 1900 metal boxes bad. 15A commercial grade plugs for 20a loads ok these days. Sideways outlets and them only available in single or at most dual outlets at times fine but other times not sufficient. There are dual sided duplex or quad cord mountable boxes on the market that will fill the bill of doing it yourself, but I am dubious about strain relief for them. 12/3 if not 10/3 would be more proper given multiple outlets in any multi-tapping cable plugged into a 15 or 20a protecting outlet due to resistance and voltage drop. TBA is my own style which would be wire rope core for strain relief and vulcanized in molded outlets if not even lamp bases for stringers plus a three circuit option. 

For now, for Edison stringers if not even just quad boxes attached to lengths of cable, where possible I will use a power strip as opposed to 1900 box. Where not possible it is a bell box and an indicator light with a cord feeding it no longer than 3' normally or in special exception of long term primary use with indicator light 25' of grade type SO 12/3. For stingers of Edison outlets, still using the two cables into one cable mount receptacle option which I despise and refuse to repair. Thus the orchestra stringers so as to get as close of outlet spacing but in a safer more compliant way. When I see a 1900 box, I send it back to who owns it - often with wires cut for safety, or assimilate it into my stock parts storage. 1900 boxes are not safe to be using, this much less what is inside of them is normally just home owner grade in construction.


----------



## ship

len said:


> I can't imagine doing that. At roughly 4 amps or more per fixture, that would be more power than the typical 15 amp circuit could handle. At most I run 2 moving lights on a circuit. Mostly, I'm working in hotel ballrooms and we're not allowed to use the panel without paying a hefty premium for the house electrician to open the electrical panel. And if the client's budget can't handle it we have to work around it. We have to design the rig based on available wall power. A pain, but a reality. So having 12 gauge wire isn't worth the expense.



Yep, know what it's like in not just doing what is worth the effort and tapping many outlets but also in figuring out how the place in an enginnering sense over those on site recommendations or thoughts as to how the place is wired because those on site often have no clue. Hmm, this outlet feeds that outlet and that one is unique to breaker or is that next outlet on the wall while in a different location on the same circuit breaker. Those that have to deal with such problems often by experience in building wiring either minimize, do long cable runs to remote sources in knowing or find out during the show because it takes time for a breaker to overheat. High respect also for you in dealing with such things, would drive me up a wall short of drawing up a wiring diagram and tracing the circuits of each place I go to before I do the load in.

But on the other hand, in more modern industry type wiring situations, the branch breakers are for 20a loading not persay all inclusive logically but in providing more power in logical plalces seperate from where others are circuited 20A but in a sting of them. It is only in older situations you would run across same circuit 15A convience outlets strung along say a length of wall or even both sides of it dependant upon the situation. Depends upon the situation and modern building as to construction for the need to plug the haze machine into a maintinence closet as opposed to other outlet in even the halllway. Challenge is more in the building and it's wiring than the actual breaker ofter once you figure out where to power up from - god bless the kitchen power sources.

Respect that concept of cable sizing in not only cost but at times it easier to mask a smaller cable, but that is for skilled labor that would know what size cable to choose for a situation and not be expected to use a 14ga cable to feed a 20A stringer. If not sure or in idiot proofing, 12/3 SOOW would be safe to use in general and standard in my opinion, this if not 10/3 for longer lengths.


----------



## avkid

ship said:


> 12/3 SOOW would be safe to use in general and standard in my opinion, this if not 10/3 for longer lengths.


See, I do occasionally know what I am talking about.


----------



## SteveB

ship said:


> It is in otherwords acceptable on stage to pull 20A thru a commercial grade 15A Edison plug.



Ship,

I cannot think of any portion of any electrical code I've ever read that allows this. Note my phrasing, as I make no claims to be expert on the US National Electrical Code.

I am assuming that the scenario you are describing indicates that the 20 amp circuit is protected by a 20 amp overcurrent device, and that all (other) electrical devices connected to this 20 amp fuse/breaker are rated at 20 amps, except for the 15 amp connector. 

This 15 amp connector now becomes the weakest link in the circuit, defeating the intent of the overcurrent protection. That is certainly not allowed by code. 

I am currently racking my brain to remember where this recently came up, all related to power strips, number of connections downstream, etc...

Steve B.


----------



## gafftaper

Here's the article from LEX's website about the redesign of their E-string product. 

We got the change that prohibits the receptacles from facing up. However the one we missed is if the cord has 4 or more receptacles, the male plug at the beginning of the cord can't be NEMA 5-15, It has to be NEMA 5-20 now.


----------



## JD

SteveB said:


> This 15 amp connector now becomes the weakest link in the circuit, defeating the intent of the overcurrent protection. That is certainly not allowed by code.



The only real solution to this whole mess is to make it up out of 12/3, but label the whole darn thing 15 amps! 

It's all kind of a catch-22 based on the angle of the plug blade. I once thought I was wise and made up a bunch with the (male) right angle blades- Ended up cutting them all off after about a month! For a traveling show, you end up condemning yourself to a standard that is not too standard! We'd set up follow spots, be shown the "20 amp plugs" in the theater, and sure enough they would be straight blade! Now, you could sit there and argue with every venue owner about it, and be right... But you wouldn't get invited back much


----------



## BillESC

But there is a 5-20 to 5-15 adapter available.


----------



## JD

BillESC said:


> But there is a 5-20 to 5-15 adapter available.



Hee hee! The first generation of Crown Microtec (spelling?) power amps all came through with the angle blade as they had a 20 amp draw. Packed in with the amp was the 5-20 to 5-15 adapter! I always found that funny! It's like their saying- "Hey, we want to do things right here but we know you all live in the real world."


----------



## derekleffew

Gentlemen, it was a 5-15 to 5-20 adapter. Male end FIRST. You two know better.


----------



## JD

derekleffew said:


> Gentlemen, it was a 5-15 to 5-20 adapter. Male end FIRST. You two know better.



Picky picky!  But you're right!


----------



## gafftapegreenia

Is it male end first because that would be the order in which incoming current would run?

Of course most people don't realize/know this rule so I usually have to specify a "male _________ to a female __________ "


----------



## derekleffew

gafftapegreenia said:


> Is it male end first because that would be the order in which incoming current would run?


It's "male end first" because we are a patriarchal society and stage work is/was dominated by male chauvinist pigs and that's what was decided by the Broadway Lighting Shops many years ago, and, since it appears in just about every textbook on stage lighting (usually in the "shop order" section), *it's the law. */rant off.


----------



## gafftapegreenia

Oh...................

I liked my version better.

Reminds me of the story of the plumber who sold ball valves for $5 and butterfly valves for $30. People will pay more for the "nice" term.


----------



## BillESC

Of course if you were to look at it from the task perspective, you are adapting a 5-20 to a 5-15


----------



## tgates

SteveB said:


> Ship,
> 
> I cannot think of any portion of any electrical code I've ever read that allows this. Note my phrasing, as I make no claims to be expert on the US National Electrical Code.
> 
> I am assuming that the scenario you are describing indicates that the 20 amp circuit is protected by a 20 amp overcurrent device, and that all (other) electrical devices connected to this 20 amp fuse/breaker are rated at 20 amps, except for the 15 amp connector.
> 
> This 15 amp connector now becomes the weakest link in the circuit, defeating the intent of the overcurrent protection. That is certainly not allowed by code.
> 
> I am currently racking my brain to remember where this recently came up, all related to power strips, number of connections downstream, etc...
> 
> Steve B.


Thats what has never made sense to me about this code, it's perfectly OK to plug a 16 gauge, 10 amp cable into a 20 amp receptacle. However the plugs are designed to stop you from plugging a safer 20 amp cable into a 15 amp outlet? In case A you stand a considerable chance of accidentally overloading a 16 (or less!) gauge cable if you don't know what you are doing. In case B, well, you might blow a breaker if you happen to have a single device that is actually fully 20 amps, but, it's far more likely the outlet would get overloaded in other ways.


----------



## Charc

I like Greenia's version too. If you look at it from a power origin standpoint:

Power Plant > Power Lines > Distribution > Cat in closet


----------



## ship

SteveB said:


> Ship,
> I cannot think of any portion of any electrical code I've ever read that allows this. Note my phrasing, as I make no claims to be expert on the US National Electrical Code.
> I am assuming that the scenario you are describing indicates that the 20 amp circuit is protected by a 20 amp overcurrent device, and that all (other) electrical devices connected to this 20 amp fuse/breaker are rated at 20 amps, except for the 15 amp connector.
> This 15 amp connector now becomes the weakest link in the circuit, defeating the intent of the overcurrent protection. That is certainly not allowed by code.
> I am currently racking my brain to remember where this recently came up, all related to power strips, number of connections downstream, etc...
> Steve B.



I'm noting on the LEX products E-String change news item that it was UL that recommended the change to their E-Strings, not persay compliance with the NEC where a few members of the company if I remember correctly sit on the board. 

Of the NEC 2002 Handbook version of the code (sorry didn't buy the latest version)
Granted article 406.7 Noninterhangeability is what supports your argument for general purpose correctness, there is an exception to it that I remember for stage usage that was clarified later publically if not in later code books.

Article 520.9 notes says 

“The stage set lighting and associated equipment, such as stage effects, both fixed and portable, must be as flexible as possible. Connectors are often used for different purposes and are therefore marked on a show-by-show basis as to the voltage, current and type of current actually employed. The provisions of 520.9 only require that connectors be rated sufficiently for the parameters involved, thus permitting connectors with voltage and current ratings higher than the branch-circuit rating to be used. ...”

This is not the article I was thinking of but is similar in showing for production usage there are some exceptions written in for use of plugs in situations other than the plug's spec. 

Still this is not the Edison exception I was looking for. I do very specifically remember reading either in a proposed or change to the NEC specific to the article 520 area, or clarification if not even IESTA tech brief on the subject that 15a Edison plugs of commercial grade (the only type of plug allowed for use on stage - another rule I remember but don't see easily found) are acceptable in place of a 20a one. I do remember this being a clarified acceptable alternative to using 20a plugs. Granted I also cannot find the article/paper.

Lex Product's change is a safety thing in I would assume making the cable assembly safer for use by non-qualified personel - band teachers etc. and sensible for a general product as would using a 20A plug for a 20A load as a general concept. I can understand why UL would request the change but also note a lack of NEC requirement to do this stated in the article and it would be were it the rational and or requirement. http://www.lexproducts.com/technical/estring_redesign.aspx 

But as stated above - frequently such 20A plugs confuse stage hands even where there is a 20a outlet available for use. Granted this confusion would go against the concept of "qualified personel" using the equipment that is the base of exception, as with commercial/industrial grade plugs where it is the exact same plug just different pin configuration also assumed to be in use which is in use by the "qualified personel". Lack of professional "qualified personel" oprating equipment never ceases to amaze me and I'll leave it at that.

Have to leave this question at a draw until either of us stumble upon the exception that on my word was specifically mentioned in the NEC at one point recently if not is the current rule.

This and also a NEC rule I didn't see in a quick search but know is also there that on a 20A branch circuit with more than one outlet it is permissible to use 15a outlets for those multiple outlets.


----------



## SteveB

ship;77939This and also a [autolink said:


> NEC[/autolink] rule I didn't see in a quick search but know is also there that on a 20A branch circuit with more than one outlet it is permissible to use 15a outlets for those multiple outlets.



I too was curious as to why it was UL that asked for the change in the LEX designs, especially the left/right outlet design versus on top, when that seemingly would be a NEC issue. UL usually just tests for fire rating and such, where as this almost seems an issue for OSHA and NEC, in terms of how a product is used. 

As to 15 vs, 20, when you think about, and as comment to another post about 16 gauge wires, the NEC (as well as UL for that matter) essentially allows 16 and 18 gauge zip cords, as well as devices whose cables are not rated at the load protection. 

The key is the DEVICE is the end user and the wiring need not be the same rating as a circuits over-current protection, and doesn't need to be, as the presumption is that the device load is not greater then the supplied cabling and plug. That's a UL issue.

That is not the same as extension cords, where you cannot (or should not) use connectors and cabling rated lower then the over-current protection and where the devices downstream may well pull a load greater then the capacity of the extension cord.

I have the 2005 NEC book at work and will see if I can find what you're refering too. Could be you are correct, though it goes against everything I've ever learned about electrical safety to prevent the connectors and cabling being a fused link in a circuit.

Steve B.


----------



## JD

Which begs the question, why can a homeowner walk into home depot and buy a 16/3 (or 18/2) extension cord ??? 

I have never for the life of me understood why this is the case! How many times do you hear about house fires that were caused by heaters being plugged into under gauge extension cords? Look at those 18/2 zip cord extension cords, and they have a UL label on them! This would give the user the false impression that it is safe. (Of course if you bother read the fine print there is a load limit.)

I think this is a case where something is so popular that no one even tries to regulate it. I know, if you are extending a table light, it would seam stupid to run a chunk of 12/3, yet, that is actually what the "device" rules would imply, as the extension cord is not the "device." 

I had to chuckle on my last trip to Disney World. They have all these 22 gauge Christmas light sets plugged into 12/3 feeders! 

Early on, (think 35 years ago) I had an electrician tell me that anything past the outlet is considered "temporary" and the rules don't apply. I am sure glad that is not the case in the theater environment! And we won't even talk about the "self electrocution chair" called the Edison light bulb base found in those table lamps! (Rant covered elsewhere.) One thing is for sure, in the home, "temporary" wiring can be equated to the wild wild west!


----------



## SteveB

JD said:


> Which begs the question, why can a homeowner walk into home depot and buy a 16/3 (or 18/2) extension cord ???



On a recent trip into HD, I picked up a short (2ft.) extension made out of 12/3, terminating in a 3 way tap. Granted it's only rated at 15 amps, as per the pin config. of the male connector, but my observations were that HD is now carrying a lot more extension cords in heavy gauge cabling then I remember. They had a few 16 ga. zip extensions, but some 14 ga. zip with grounded male and grounded 3 way female, as well. 

So maybe that's a trend, away from the non-grounded 18 and 16 ga., 5 and 10 amp, non-grounded crap, towards stuff that actually won't burn your house down. And maybe the big box companies don't want the liability issues. 

Steve B.


----------



## STEVETERRY

ship said:


> I'm noting on the LEX products E-String change news item that it was UL that recommended the change to their E-Strings, not persay compliance with the NEC where a few members of the company if I remember correctly sit on the board.
> Of the NEC 2002 Handbook version of the code (sorry didn't buy the latest version)
> Granted article 406.7 Noninterhangeability is what supports your argument for general purpose correctness, there is an exception to it that I remember for stage usage that was clarified later publically if not in later code books.
> Article 520.9 notes says
> “The stage set lighting and associated equipment, such as stage effects, both fixed and portable, must be as flexible as possible. Connectors are often used for different purposes and are therefore marked on a show-by-show basis as to the voltage, current and type of current actually employed. The provisions of 520.9 only require that connectors be rated sufficiently for the parameters involved, thus permitting connectors with voltage and current ratings higher than the branch-circuit rating to be used. ...”
> This is not the article I was thinking of but is similar in showing for production usage there are some exceptions written in for use of plugs in situations other than the plug's spec.
> Still this is not the Edison exception I was looking for. I do very specifically remember reading either in a proposed or change to the NEC specific to the article 520 area, or clarification if not even IESTA tech brief on the subject that 15a Edison plugs of commercial grade (the only type of plug allowed for use on stage - another rule I remember but don't see easily found) are acceptable in place of a 20a one. I do remember this being a clarified acceptable alternative to using 20a plugs. Granted I also cannot find the article/paper.
> Lex Product's change is a safety thing in I would assume making the cable assembly safer for use by non-qualified personel - band teachers etc. and sensible for a general product as would using a 20A plug for a 20A load as a general concept. I can understand why UL would request the change but also note a lack of NEC requirement to do this stated in the article and it would be were it the rational and or requirement. http://www.lexproducts.com/technical/estring_redesign.aspx
> But as stated above - frequently such 20A plugs confuse stage hands even where there is a 20a outlet available for use. Granted this confusion would go against the concept of "qualified personel" using the equipment that is the base of exception, as with commercial/industrial grade plugs where it is the exact same plug just different pin configuration also assumed to be in use which is in use by the "qualified personel". Lack of professional "qualified personel" oprating equipment never ceases to amaze me and I'll leave it at that.
> Have to leave this question at a draw until either of us stumble upon the exception that on my word was specifically mentioned in the NEC at one point recently if not is the current rule.
> This and also a NEC rule I didn't see in a quick search but know is also there that on a 20A branch circuit with more than one outlet it is permissible to use 15a outlets for those multiple outlets.


I think you might be referring to a part of 520.67 *Multipole Branch Circuit Cable Connectors*:
.......The connector shall be rated in amperes and designed so that differently rated connectors cannot be connected together; however a 20-ampere T-slot receptacle shall be permitted to accept a 15-ampere attachment plug of the same voltage rating...............

That is not the same thing as 15A outlets on a 20A branch circuit.

However, Section 210.21(B)(3) and Table 210.21(B)(3) do allow either 15A or 20A outlets on 20A branch circuits with two or more outlets.


ST


----------



## Chris15

Hmm... That took me a while to read and I'm not sure I've properly digested it. I'm going to add some thoughts from down here, your rules and my rules aren't the same, we all know that, so as always, check your rules before you start wiring things up.

Any device having multiple outlets connected through to a single plug MUST have a circuit breaker, rated to the total capacity of the device, so if it has a 10A plugtop and cable, then your breaker should also be 10A. Now bear in mind that 10A is the normal everyday socket around here, but if you have a device fed by say a 15 or 20A plug, you can have a 15 or 20A socket on it, but you can only have one such outlet, any other outlet may only be 10A.

Our plugs and sockets are designed such that you can plug a 10A plug into a 10, 15 or 20 A socket, a 15A plug into a 15 or 20A socket and a 20A plug into a 20A socket. And I have no problem with that. The plug and cable need only to be rated at the current draw of the appliance, while the breaker is there in reality to protect the wiring installed in the walls which, if it were to catch fire, would be much harder to control than a piece of flex.

In building wiring, I think the rules are that you can have up to 8 GPOs on a 20A breaker or 1 15A outlet or 1 20A outlet. But of course for certain high current appliances or for other reasons, you may want things on their own breakers. Nothing to stop the use of a 10A or even down to I think 1A breaker if that's all a circuit needs - control circuits would be the main users of such small breakers.

Oh and one cannot legally have a cable down here that has a plug and socket of different current ratings. If the socket is of lower rating than the plug then it would be perfectly safe, but it was just easier to write a blanket rule...

And to be honest, the original post was starting to trigger the if you have to ask you shouldn't be doing it alarm...

Food for thought...


----------

