agoolay

Split circuit to a receptacle. Say you run a 12-3 nm cable to a Spa with a heater. The heater pulls something like 12.5 amps and the pump pulls say 9 amps.(Just pulling figures out of my head) You make it a split circuit to the one receptacle and you break the tab in the middle on the hot side. One plug-in would have it's own circuit to operate the pump and the other plug-in would have it's own circuit to operate the heater and they share the same neutral. Would this be legal?

I would think it depends on how you have the circuits hooked up in the panel box. If you have both the red and black conductors on the same phase it would be legal. Illegal if both the red and black is on different phases. My reason why is the receptacle are only rated 125v and if you have both hot conductors on different phases then you now have 240 voltage to a 125v rated receptacle. Thus making it illegal.

Agree or disagree?

HCECalaska

the nec allows you to run a 12-3 to a duplex receptical and have a dedicated circuit to each out let. to do this you must have the 2 hot conductors terminated on a 2 pole breaker.. yes this means there is 240 in the box but this is ok and legal. the problem with haveing both wire on the same phase is the neutral could carry upto 40amps which excees the rating of the 12g neutral. if there are 2 phases on the same neutral then the neutral carries the unballanced load. if A phase is 15amps B phase is 10 amps the neutral carries 5 amps.

agoolay

Yep, your right about the neutral load which I hadn't even thought about! Do you know right off hand what code that is that makes it legal? I do seem to remember something about a split circuit has to be on a double pole breaker now that you mention it.

MDShunk

Just keep in mind that if this if for a jetted tub, such as your example seems to be, you're going to be GFCI-ing those circuits. No tabs to break out of a GFCI, and 2-pole GFCI breakers are a tad pricey. You might have to think of a different design idea. I generally run a 12-3 on 2 single poles, terminated at two GFCI receptacles. Most often mounted in a 4" square x 2-1/8" deep metal box with an RS cover for 2 GFCI's mounted just inside the motor access panel.

agoolay

True, that's how I'm use to doing a heated spa also. After posting my reply last night I looked the code up for using a 125v rated receptacle for a split circuit and it is legal regardless of the rating, so long as you break the tab out. And I have done this many times but I just got to thinking about that recept is only rated 125v and could a inspector throw that against you. The answer is "no".

HCECalaska

the code section 210.4 (B) Devices or equipment: where a multiwire branch circuit supplies more than one device or equipment on the same yoke, a means shall be provided to disconnect simultaneously all the ungrounded conductors supplying those devicesor equipment at the point where the branch circuit originates.

HCECalaska

where i have seen this installation done most commonly is for a disposal/ dishwasher setup under the sink.

HCECalaska

each of the recepticals of the duplex receptical is rated at 125v on a duplex receptical there are two recepticals on one yoke. so there is no conflict with this.