[Sime]

I have a couple of receptacles that I am planning on wiring in the theater.


This is a four gang box that I plan to put about 2-3 double 20 amp receptacles into with the fourth being for a coaxial for my cable tv. It's a dedicated circuit. I don't think I'll use all receptacles at once (I need four though to power the equipment), but I'd like to have them there. BTW, I'm using 12/2 wire.


What is the correct/legal NEC process for wiring these receptacles from a single 12/2 line entering into the box? Do I run three receptacle grounds and pigtail them to the incoming ground, and do the same with my neutral and hot to each receptacle, or wire them all in series? If they were pigtailed, I'd have 4 x 12 gauge wires together (that's a big wire nut!!). Is that ok?


What's the maximum # of receptacles I can wire up to the one incoming wire entering the box?


Also, with regards to hidden boxes and NEC, I have to join some wire that was cut too short. I am planning to join the two lengths in a gang box in the ceiling and then run the new length from here to the new fixture. Is it legal to access the box by removing a light fixture, or do I need to feed new wire through to the fixture from the original source and forget the box in the ceiling?


Looking for the correct way so that I don't start any fires!! Many thanks!


Simon

 

[Larry Fine]

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Originally posted by Sime I have a couple of receptacles that I am planning on wiring in the theater.

How can we help?

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This is a four gang box that I plan to put about 2-3 double 20 amp receptacles into with the fourth being for a coaxial for my cable tv. It's a dedicated circuit. I don't think I'll use all receptacles at once (I need four though to power the equipment), but I'd like to have them there. BTW, I'm using 12/2 wire.

Problem: you can't legally and shouldn't have power and low-voltage wiring in a single box without a fixed barrier. I suggest separate boxes, several inches apart. There will be less electrical interference induced in the coax cable.

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What is the correct/legal NEC process for wiring these receptacles from a single 12/2 line entering into the box? Do I run three receptacle grounds and pigtail them to the incoming ground, and do the same with my neutral and hot to each receptacle, or wire them all in series? If they were pigtailed, I'd have 4 x 12 gauge wires together (that's a big wire nut!!). Is that ok?

You can do it either way. I did mine 'daisy-chained', what you called 'in series', except for the ground. I left the ground from the incoming NM cable ling, and looped it from receptacle to receptacle. That left me the black and white wires to jump from one receptacle to the next.


Four #12 wires in one wirenut is not a problem; use the red wirenuts.

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What's the maximum # of receptacles I can wire up to the one incoming wire entering the box?

No real limit. What matters is that you don't overload the circuit, electrically speaking. Add up the wattage and/or current consumption (volts x amps = watts) of everything you expect to plug into the circuit. Code calls for a max of 80% (16 amps/1920 watts). If you're nearing this, use two circuits.

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Also, with regards to hidden boxes and NEC, I have to join some wire that was cut too short. I am planning to join the two lengths in a gang box in the ceiling and then run the new length from here to the new fixture. Is it legal to access the box by removing a light fixture, or do I need to feed new wire through to the fixture from the original source and forget the box in the ceiling?

Yes, you may splice a wire in an existing box, or install a new box, and hang a fixture from it. I've used that method several times; I installed a new receptacle when I needed to extend a light's switch wiring (widening a doorway opening.) The only caveat is to not overload the box's fill capacity. (Heat build-up is the concern - 40% fill limit)


Most boxes are marked with the fill limits, a different quantity for each size. Each wire entering (or leaving) the box is 1, all grounds together count as 1, a device (switch or receptacle) that goes into the box is 2, and wires that stay within the box (such as pigtails) don't count.If you mix 12 & 14, you have to calculate. Let me know if you need help with that.


(Between you and me, the less loaded the circuit(s) are loaded, the less critical box fill is, but the inspector will check for obvious violations.)

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Looking for the correct way so that I don't start any fires!! Many thanks!

You're very welcome.

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Simon

 

[Sime]

Larry, thanks ever so much (again!!! ) for the help.


I'll separate the power gang boxes from the low voltage coaxial/telephone in a new box per your recommendation. Also will be careful not to overload the circuits!


So, it is 'ok' then to daisy chain the hot and neutral from receptacle to receptacle? Can you do this with the ground as well? If not, I guess I would daisy chain hot and neutral, and wire nut the grounds together and distrubute them to each receptacle. Would this combo work?


Also, where I have a double receptacle in the middle of a run, is it code acceptable to hook the incoming 12/2 to the upper of the two outlets and then wire the outgoing wiring to the lower of the two, leaving the receptacle (removable) 'bridge' to continue the circuit?


Or, do I need to pigtail the hot and neutrals so only one hot/neutral is connected to the receptacle? Think I read this in the Home Depot Electrical book!!!


Thanks again!!


Simon

 

[chrispy]

I separated my low-voltage from the AC receptacles as well. For my 4-gang box with four duplex outlets, I daisy-chained them in serial off the single incoming 10-2 feed. My 20A audio circuit uses 20A outlets capable of accepting 10-2 Romex. Overkill? Sure, but the price difference was a few bucks.


- Chris

 

[Sime]

I am also using 20amp receptacles too. I thought it a good idea to spend the extra. Even got the grey color as well!


Chris, when you daisy chained, did you leave the bridge in, and have the incoming at the top outlet and the outgoing at the bottom outlet, going to the next in line receptacle (at the top)?


What did you do with the ground?


Thanks,

Simon

 

[Larry Fine]

Sime, et al, it is acceptable to daisy-chain. Some people prefer to wirenut, which is also okay, but not necessary, except where more than one circuit shares a neutral, in case someone disconnects a receptacle on one circuit.


They would shut off the breaker on that circuit, but might leave the other one on. Since these multi-wire circuits don't require tie handles (unless they feed the same device, but still should be side-by-side in the panel), shutting off one circuit would not eliminate all of the neutral current.


Since the ground only has one screw (which is done so one ground connection is not dependent on another, like if you were to remove one receptacle on a circuit), I would just strip the cable long, and loop the single bare single wire from screw to screw to screw.


Again, this long stripping would give you the black and white wires to cut the jumpers from. (You know how much we electricians hate wasting wire!) Only aluminum wiring requires wirenutting and pigtailing.


As an alternative, you can also loop them, and only use one screw on each receptacle. Of course, this would require stripping about one inch of wire every six inches along these wires, but it's been done.

 

[Sime]

Thanks Larry, that makes total sense. I guess you'd have to remember to leave enough 'extra' wire to run the continuous ground!!


Not sure if you missed the other question (or if I missed your answer!!), but where I have a two outlet receptacle in the middle of a run, is it code acceptable to hook the incoming 12/2 to the upper of the two outlets and then wire the outgoing/continuing wiring to the lower of the two, leaving the (removable) 'bridge' to continue the circuit?


Thanks ever so much!

 

[Larry Fine]

Of course; that's exactly how they're intended to be used, just like when doing the 'daisy-chaining'. Just keep the colors right: black to brass, white to silver. As an additional telltale sign, the ground screw is always on the same side as the white. I don't know why. Nobody tells me anything.

 

[Ken Greene]

the ground (green) screw is on the same side as the nuetral( silver) screw to keep the hot (Brass ) screw appart from anything that may complete the circuit and short out the wire if the breaker wasn't off and someone or something crossed the contacts.