Recept. Branch

[mstrlucky74]

So I questioned someone today on how they drew in branch circuity on drawing. There were about 15 receptacles every 5-6 were on a circuit so he grouped/tied them all together. Basically MWBC. He said he was running 12/6 MC(he says they make it..I've heard of super BX)and each circuit would have a separate neutral. Just from a wiring standpoint wouldn't it be PIA to run 12/6 to first receptacle and splice through? How about box fill? Thanks

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[david]

So I questioned someone today on how they drew in branch circuity on drawing. There were about 15 receptacles every 5-6 were on a circuit so he grouped/tied them all together. Basically MWBC. He said he was running 12/6 MC(he says they make it..I've heard of super BX)and each circuit would have a separate neutral. Just from a wiring standpoint wouldn't it be PIA to run 12/6 to first receptacle and splice through? How about box fill? Thanks

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if its 12/6 each circuit having its own neutral than it would not be a multiwire branch circuit.

ill take your word for it that they manufacture the cable, never seen it, if the correct box is used i do not see box fill as an issue

 

[mstrlucky74]

if its 12/6 each circuit having its own neutral than it would not be a multiwire branch circuit.

ill take your word for it that they manufacture the cable, never seen it, if the correct box is used i do not see box fill as an issue

Your right about MWBC..my oversight.

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[ActionDave]

.,..Just from a wiring standpoint wouldn't it be PIA to run 12/6 to first receptacle and splice through? How about box fill? Thanks

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I would not do that. I would run to a j box in the ceiling and branch out from there to the recpts.

 

[mstrlucky74]

I would not do that. I would run to a j box in the ceiling and branch out from there to the recpts.

That's what I said...

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[infinity]

I would not do that. I would run to a j box in the ceiling and branch out from there to the recpts.

That's what I said...

I agree, who wants to bring 6 circuits into a receptacle box.

 

[WarrMann]

I agree, who wants to bring 6 circuits into a receptacle box.

Someone who thinks they're slicker than typical wiring methods. Ive never seen that type of cable in the wild.


3 wire romex costs almost twice as much as 2 wire, i can only imagine what 6 wire romex would cost, let alone 6 wire MC. It's probably priced the same as it's weight in gold.


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[Johnhall30]

Wouldn't you have to run 10/6 to the first receptacle, because you have 6 conductors in a single raceway? You would have to de-rate the wire by 80%

 

[WarrMann]

OP is taking about MC. So no derating.

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[Johnhall30]

OP is taking about MC. So no derating.

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Conductor derating does not apply to MC cable?

Table 315.10(B)(3)(a) says - "Number of conductors is the total number of conductors in the raceway or cable,"

 

[WarrMann]

Table 315.10(B)(3)(a) says - "Number of conductors is the total number of conductors in the raceway or cable,"

That's fair, i misspoke. I guess ive just never run into it, as most cables I've used with more than 3 ccc in them were for branch circuits. And 80% of 25 amps is 20, so still no derating required for an outlet branch circuit

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[Johnhall30]

That's fair, i misspoke. I guess ive just never run into it, as most cables I've used with more than 3 ccc in them were for branch circuits. And 80% of 25 amps is 20, so still no derating required for an outlet branch circuit

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Good point. I did not consider the ampacity of #12 in MC cable to have an ampacity of 25A. However, the ampacity of #12 NM cable is limited to 20A, correct? MC cable can use the ampacity in the 75º column.

 

[WarrMann]

Good point. I did not consider the ampacity of #12 in MC cable to have an ampacity of 25A. However, the ampacity of #12 NM cable is limited to 20A, correct? MC cable can use the ampacity in the 75º column.

In general, #12 is limited to a 20 amp ocpd per code. (I can't always shoot from the hip with article references)

The 75 degree rating will usually come down to the terminals the wire is terminating into.

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[infinity]

Actually I read it wrong it's 3 circuits with 6 conductors. 6 CCC's derating is 80%.

30*80%=24 amps so the cable is fine with 6 CCC's.

 

[mwm1752]

I've used multiple conductor MC similar for swamp cooler switch legs - works great - but there was only 1 grounded conductor which would lead into 200.6 for identification of a 12# ga grounded conductor - the 6 conductor would have a properly identified pair neutral with its corresponding ungrounded conductor to be compliant.

 

[Strathead]

MC can be ordered in virtually any color configuration. They make MC that is "standard" not stocked but standard that has, for example the colors for what the call a 7 wire furniture whip. 3 hots with shared neutral, 1 hot one neut one green yellow ground and one green ground. for example. But if you want it they will put it up. It may be subject to minimums. My experience is that unless you are in an area where labor rates exceed $60 it is cost prohibitive.

 

[mstrlucky74]

I agree, who wants to bring 6 circuits into a receptacle box.

3 circuits not 6.

 

[infinity]

3 circuits not 6.

Yup, post #14.