quote:

---

I bought a copy of the 2002 National Electrical Code (NEC) last evening. I looked up the requirements for bathroom circuits, and now I have a question: Is it ok to have a single, 20-amp circuit supply both lights and an outlet in a single bathroom?

To begin, I point you to 210.11(C)(3), which says: "...at least one 20-ampere branch circuit shall be provided to supply the bathroom receptical outlet(s). Such circuits shall have no other outlets."

So it would seem that I can't supply my lights from the same circuit. But wait! There's the following exception in the next paragraph: "Exception: Where the 20-ampere circuit supplies a single bathroom, outlets for other equipment shall be permitted to be supplied in accordance with 210.23(A)."

In 210.23(A) I find: "A 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both..."

The exception makes it appear that, because I'm supplying a single bathroom, I indeed can supply both the lights and the outlet. However, there's an exception to the exception! Under 210.23(A), I also find: "Exception: The small appliance branch circuits, laundry branch circuits, and bathroom branch circuits required in a dwelling unit(s) by 210.11(C)(1),(2), and (3) shall supply only the recepticle outlets specified in that section."

I'm now in an circular loop. The exception in 210.11(C)(3) points me to 210.23(A), and then the exception in 210.23(A) points me right back to 210.11(C)(3).

Do I not follow the second exception? Does code allow me to service all of a single bathroom with a single circuit? It should we be convenient. One room/one circuit makes it much easier to label the breakers.

---

Here is the readers digest condensed version. You can use one twenty ampere circuit to supply the basin receptacle outlets in several bathrooms OR you can use one twenty ampere circuit to supply the receptacle and other loads in a single bathroom. So you can do exactly what you want to do and still be code compliant.

You should realize however that being code compliant "will result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use." If you overload that circuit the bathroom can be plunged into darkness if the entire room is supplied from only one circuit. It is simply good practice to see to it that every room in your home has at least two circuits supplying outlets in that room. One rather good way to accomplish this is to use a multiwire branch circuit to supply each bathroom. One side of that circuit then supplies only the basin receptacle. The other side of the circuit supplies the remainder of the bathrooms outlets. This will allow you to have a lot of lighting, a ventilation fan, and a bathroom heater up to 1200 watts without any risk of overloading either circuit. If the loads in the bathroom will be limited to a couple of lights and a small vent fan then the regular two wire circuit would work for the entire bath including the basin receptacle. If a single circuit is used I recommend that one light be supplied from the general lighting circuit that supplies the lights to adjacent areas.
--
Tom

90.1 Purpose.
(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance will result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

I would 2nd Tom's advice, and only add this passage for consideration which includes Handbook Commentary;

from 210.52(D),

(D) Bathrooms. In dwelling units, at least one wall receptacle outlet shall be installed in bathrooms within 900 mm (3 ft) of the outside edge of each basin. The receptacle outlet shall be located on a wall or partition that is adjacent to the basin or basin countertop.

Handbook Commentary here:

Section 210.52(D) requires one wall receptacle in each bathroom of a dwelling unit to be installed adjacent (within 36 in.) to the washbasin. This receptacle is required in addition to any receptacle that may be part of any luminaire or medicine cabinet. If there is more than one washbasin, a receptacle outlet is required adjacent to each basin location. If the basins are in close proximity, one receptacle outlet installed between the two basins might satisfy this requirement. See 410.57(D), which prohibits installation of a receptacle inside bathtub and shower spaces. See Exhibit 210.9 for a sample electrical layout of a bathroom.
Section 210.11(C)(3) requires the receptacle outlets to be supplied from a 20-ampere branch circuit with no other outlets. However, this circuit is permitted to supply the required receptacles in more than one bathroom. If the circuit supplies the required receptacle outlet in only one bathroom, it is allowed to also supply lighting and an exhaust fan within that bathroom. This receptacle is also required to be GFCI protected according to 210.8(A)(1).

Well, you could blame it on the fact that I edit technical books for a living. And I do happen to be working on a bathroom right now....

Thanks guys, for your input on this. That's an interesting point about not wanting the lights to go out when one overloads a circuit (e.g. by using a blowdryer or whatever). In this particular bathroom, I don't see that as much of a problem, but it's definitely something I'll keep in mind as I work on other parts of the house.

To be honest, I didn't even put in an outlet this time. I just want the option of adding one in the future, and on that same circuit. I started with an existing bathroom with only a single light fixture, and no outlets. That fixture was the first on a circuit that serves all the basement lights and outlets (old house). I replaced the one fixture with two, and in the process disengaged the original fixture from the old circuit and placed both lights on a new circuit hanging off a GFCI breaker. So I now have a 20-amp circuit running 69 watts worth of fluorescent lights in my bathroom.

I suppose you could argue that I should've put in an outlet too, and perhaps I should have, and perhaps I will now that I know that it belongs near the sink. It's easy enough to add. I just need to run a few feet of conduit down from the floor joists above. This isn't a finished room like the bathrooms upstairs.

you'll be fine!