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Making extension cords and quad boxes

Discussion in 'Lighting and Electrics' started by Daveslights, Jan 20, 2008.

  1. Daveslights

    Daveslights Member

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    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
     
  2. SerraAva

    SerraAva Active Member

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    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.
     
  3. zac850

    zac850 Well-Known Member

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    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
     
  4. SteveB

    SteveB Well-Known Member

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    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.
     
  5. SerraAva

    SerraAva Active Member

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    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 :twisted:.

    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.
     
    Last edited: Jan 20, 2008
  6. soundman

    soundman Well-Known Member

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    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.
     
  7. len

    len Well-Known Member

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    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?
     
    Last edited: Jan 20, 2008
  8. BillESC

    BillESC Well-Known Member Premium Member

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    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.
     
    Last edited: Jan 21, 2008
  9. SteveB

    SteveB Well-Known Member

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    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.
     
  10. avkid

    avkid Not a New User Fight Leukemia

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    Eh...Wrong answer.
    12/3 SOOW
     
  11. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    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.
     
  12. len

    len Well-Known Member

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    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.
     
  13. SHARYNF

    SHARYNF Well-Known Member

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    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
     
  14. len

    len Well-Known Member

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    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.
     
  15. SHARYNF

    SHARYNF Well-Known Member

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    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
     
  16. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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

    avkid Not a New User Fight Leukemia

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

    len Well-Known Member

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    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.
     
  19. ship

    ship Senior Team Emeritus Premium Member

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    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.
     
  20. ship

    ship Senior Team Emeritus Premium Member

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    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.
     

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