ECN Forum Forums Code Related Discussion NEC & other Code issues NEC 300-3(b)

hi,
try using a 4/C #10

Bordew,

I agree with you that these combination units are required to be on a 20 amp circuit, by virtue of the 1500 watt heater. 1440 watts is the 80% limit for a single load on a 15 amp circuit. And 1000 watts is the limit for any fastened in place load that could be added to the bath circuit, if the circuit is used for that one bath only (outlet, and including lights, etc.). The installation cost (a 20 amp circuit) of the heater in this combo unit is dictated by the size of the heater. No way around it.

But if I wire only the bath outlet on the 210 required bath outlet circuit (as is my option), and have the bath lighting tagged onto a general lighting circuit, what's to keep me from putting the combo unit fan/light/nitelite on the gen ltg ckt?...instead of the heater 20 amp circuit. The internal construction of the combo unit results in multiple neutrals being in its j-box for connection to the field installed wiring, so the manufacturer is making it possible for the field installer to hookup the neutrals in any grouping. It's up to the field installer to do it to code.

I understand that your AHJ wants to see one cable or conduit cause that simplifies his inspection. . .doesn't have to question the installer as to his/her understanding of 300-3(b), or open the combo's j-box to look for separated neutrals. . .but I think that's the AHJ's local spin.

Now, for the sake of discussion, in this hypothetical big bath (no jacuzzi) with two blow dryers (and maybe two bath outlet circuits. . .but that's another story. . .) what's to keep me from feeding the night light continuously (say I put in a LED bulb, less energy loss), switching the light at the door, switching the fart fan at the WC, and putting a spring wound timer for the heater at a location convenient to where one drys off? The extra work really isn't a problem cause the client is buying a really BIG bath and can afford my contract and I saw this on the prints so I included it in the contract. I feed the heater at the timer off its own 20 amp circuit, and tap the feed for the night light off the general lighting circuit and drop two switch loops to the WC and the door to the bath. By my count, I get to shoehorn one 12-2 and three 14-2s into the combo's j-box. The heater neutral is connected to the 12-2 and the rest on the neutrals are connected to the 14-2 feed.

That's what I call a version of a designer install. What do you think?

Al

Al:
As far as I can tell with the rating of this thing approx. 1400 w, I would think that would by itself require a seperate circuit, and I would think would severely limit the General lighting circuit that it was taken from.
I think it was you that mentioned the 50 % rule on the bathroom gfci circuit, that is a 10 amp load for a ceiling vent or whatever would come out in that ballpark.
You are right about the multiple neutrals in the circuit but they are confined to that box, the thing that bothers me is if one circuit is taken from the gen'l lighting circuit and another brought in from the panel, the heater, now you could inadvertantly shut off the one circuit and still have the heater hot. Also if the second circuit is taken froom the second buss now there is a possibility of 240 volts there unbeknownst to the electrician and two neutrals sort of belying that fact that there could be a higher voltage there than believed.
thats the way I look at it. Because when we go on a service call we are never really sure who did the work and the home-owner seldom owns up to especially if he screwed it up and now has a real problem. You know you get there and he suddenly develops a problem on a multi-wire circuit and one breakers is now back-fed, and you know he did something which would be a great place to start looking for the problem, but of course, he hasnt done anything to the wiring in years.
anyway just my opinion.