Q.
I am heavily involved in electrical construction for residential/commercial building.

Using 120/208V single phase 3-wire system to the apartment/condo with #6/3 armor cable, and apartment CB Panel is 1-phase, 3- wire 8/16 GE.

Is it possible to use a 12/4 armor cable in branch wiring ?
Is there be a violation of NEC ?
Is color coding cable in armor wiring is acceptable by NEC?
If there will be a color coding, making 2 neutral cable in one armor jacket is possible?

NOTE : As of my experties, and experience, the questioned armor cable is a violation of NEC and technically it's not permitted because of 2 neutral parallel in one jacket.

Appreciated for quick answer!!

Raj

You need to check with the local AHJ on this.

12-4 cable can be used for two circuits, each circuit having it's own neutral.

As you know, the neutrals must be clearly identifed, the entire length of the cable.

If the cable you have does not have two white, or gray, conductors, as per NEC 200.6, then this is a problem, unless the AHJ allows it.

NOTE : As of my experties, and experience, the questioned armor cable is a violation of NEC and technically it's not permitted because of 2 neutral parallel in one jacket.Care to tell us where you found this violation in the NEC?

rajhpd1,

I'm sure you are referring to mc cable, which is made in a 12/2/2 wgrd just for that use.

NM cable also comes in 12/2/2 and 14/2/2.

You can't Parallel Neutrals(or any conductors), unless it is greater than 1/0 or less than 50 Volts.
2 neutrals can be in same conduit /cable just not for same circuit.