120 and 277 sharing a 10/2/2 mc

[deschene00]

I'm working on a remodel where the previous electrician run a 10/2/2 MC for a 120 lighting circuit and a 277 circuit. I know you can run both in a conduit but is it ok to use MC?

 

[Dennis Alwon]

I'm working on a remodel where the previous electrician run a 10/2/2 MC for a 120 lighting circuit and a 277 circuit. I know you can run both in a conduit but is it ok to use MC?

Why not? If you can do it in conduit I can see no reason not to in MC as long as the color phasing is done.

 

[nakulak]

Never heard of anyone doing that. I don't know that it is a violation, but it sure as heck is a bad practice.

 

[deschene00]

Thanks thats quite helpful!!!

 

[LarryFine]

Shocking!

 

[hurk27]

what about sharing the neutrals from two different sources, or the grounding? are you saying a 10 awg/then 2#2 awg wires in the same MC cable? never seen a 10/2/2 cable, doesn't sound code compliant to me?

 

[LarryFine]

what about sharing the neutrals from two different sources, or the grounding?

From which panel?

 

[Jim W in Tampa]

biggest problem i see is we need a gray for 277 and a white for the 120 and not sure they can not be taped .
It sure is a bad idea but if you can get past the marking part then for lack of a " shall not" i guess it would fly

 

[jusme123]

what about sharing the neutrals from two different sources, or the grounding? are you saying a 10 awg/then 2#2 awg wires in the same MC cable? never seen a 10/2/2 cable, doesn't sound code compliant to me?

biggest problem i see is we need a gray for 277 and a white for the 120 and not sure they can not be taped .
It sure is a bad idea but if you can get past the marking part then for lack of a " shall not" i guess it would fly

see 200.6(D)

 

[infinity]

what about sharing the neutrals from two different sources, or the grounding? are you saying a 10 awg/then 2#2 awg wires in the same MC cable? never seen a 10/2/2 cable, doesn't sound code compliant to me?

10/2/2 is a cable with four #10 wires Blk/Wht and Red/Wht w/ red tracer and possibly an EGC.

 

[roger]

biggest problem i see is we need a gray for 277 and a white for the 120 .

Jim, can you point us to this requirement?

Roger

 

[CFL]

Jim, can you point us to this requirement?

Roger

I was going to say 200.6(d) but actually after reading it looks like the red tracer is enough to differentiate the two systems. In either case there is no designated color for each specific system (ie. gray for 277), just that they are different.

The first sentence of 200.6(d) mentions grounded conductors from different systems in the same cable, which seems to imply that it's ok.

 

[iwire]

I am missing the problem. I believe we all know we can mix voltages in raceways.

Why would the rules be different for cables? And if they are different for cables can someone point out that code section?

 

[Dennis Alwon]

never seen a 10/2/2 cable,

I haven't seen it either but I learned on this forum a year or so ago that it is available. Basically there are two 2 wire circuits available in the mc as Trevor stated.

They also make it in NM cable. More common is 12/2/2 or 14/2/2. It avoids the MWBC that is a problem with AFCI circuits since there is no shared neutral.

 

[Jim W in Tampa]

I agree that 200.6 does allow this if it has a white with red stripe.

 

[deschene00]

we didnt want to take a chance and get tagged so we just ran a new MC for the 120...thanks for all the help...definitely conformed what I thought about it