Even if they are the only two devices on the circuit (and I'm not sure if you can have just two on a 20a circuit) since it's 20A ALLLL wire used must be 12awg. I know it might seem academic since it's branching to a light fitting whose wires might be a low gauge, more like speaker wire.

I am in Canada so the rules are somewhat different, but that one's pretty much universal. You must run the minimum gauge throughout the circuit, at least right up to where the load joins, in the case of a light.

Theoretically you could derate the circuit by using a 15a breaker but that would probably contravene the code by the outlet being only 15a (and you would have to use a 15a outlet) since I doubt that's not permitted, you really can't do it.

Conversely, you can ALWAYS go to a heavier gauge with a lower rated circuit, ie you could use #12 or even #10 if you so desired, on a 15a circuit.

It sounds like you haven't pulled a permit for this job, if you had, the permit folks might have given you the rundown first. Probably a good idea to get one before the drywall goes up....

Im not sure if im understanding what you are asking here. If you ran 12/2 from panel to GFI that is perfect. It sounds like you splice the bathroom light onto the circuit and its fed with 14g? Is this correct? Did you pull power from the GFI to a switch then to the light???

It is *NOT* ok. If you've got a 20A breaker (which is required for the bathroom receptacle) then you can not drop the wire size down to 14 even to feed the light.

Furhter, I don't know what sort of light you put over the tub, but I'd check the legality of that as well.

(Article 406.8 B Wet Locations)
15-20 amp receptacles in a wet location

(Article 550.13 B Receptacle Outlets)
Minimal of 20Amp branch circuit, shall have GFCI protection.
GFCI protection shall be provided for receptacle outlet serving countertops in kitchen, and receptacle outlets located 6ft of a wet bar sink.

Straight from the National Code Book 2008

"(Article 406.8 B Wet Locations)
15-20 amp receptacles in a wet location "

I don't get it. Bathroom receptacles must be on a 20A circuit.
What does wet location have to do with it?

"(Article 550.13 B Receptacle Outlets)
Minimal of 20Amp branch circuit, shall have GFCI protection.
GFCI protection shall be provided for receptacle outlet serving countertops in kitchen, and receptacle outlets located 6ft of a wet bar sink."

I didn't know mobile homes had basements? Again, what's your point? Your code reference has no relevance.

Um... Electricman - Section 550 of the NEC is about mobile homes... That is why he referenced mobile homes, and the fact that the code sections you cited have zero relevance on what the OP originally asked.

ok try this one
Article 210.50
utilization equipment not fastened in place shall not exceed 80 percent of the brench-circuit ampere rating.

Wrong thread, but I know what you are getting at.

Try reading all of 210.23
Here is a snip from the first paragraph:
"An individual branch circuit shall be permitted to supply any load for which it is rated."

The 80% rule comes into play with continuous loads, individual cord connected loads and fixed in place loads. The CIRCUIT is not limited to 80%. What's plugged in usually is.

For a second there I thought we were just going to start quoting random sentences from the NEC ;)

lol. Im still learning guys. I was just trying to help some people out. I know I have a lot to learn... The Code book is still hard for me to understand. Its worded like it was wrote in the 1800s...LOL They need to make it easier to understand. Im here to learn also and I dont want to give bogus info out either. Like I said i was just trying to help.

Aaanyway, getting back to OP's original question. No disrespect intended Hoosierdoc but you sound fairly new to this which is of course ok but be very careful, and make sure you read and understand what's required of you, you seem to be mixing your terms up etc. The point you are putting a light over the bath slipped past me, my bad, make sure you are doing so in accordance to code, and using a fitting that is rated for a wet area.

Do you understand what we mean about 14ga vs 12? Apart from being a code violation on a 20a circuit, you are creating a phenomenon they used to call 'fusing' in the early computer designed printed circuit days, when some CAD software would allow circuit board tracks of different thicknesses in the same circuit, which is what essentially mixing 14 and 12 is doing, provided you are OVER RATING ie 12 on a 15a circuit it is ok because 12 is over spec, in a 20a circuit, you are at the MINIMUM so introducing 14ga is creating a thin part or potential 'fuse' which will heat up relative to the other wiring. Remember resistance increases exponentially with heat, which is how fires start; one bad connection or warm spot occurs, which makes the resistance increase - current is dissipated as heat, which creates more resistance, which means more current is dissipated as heat, etc.

You can probably buy just one yard/metre of 12/2 or whatever you need, as I said you will need an inspection done before the drywall goes up.

If you 'get away' with non-code work, and a building inspector finds it when you try to sell, you will have to pay to have it rectified - just do it right, first time.

You might want to watch "Holmes on Homes" a Canadian contractor guy who fixes other people's mistakes - it's quite illuminating.

You REALLY need to be careful then about what you post as fact or code. Be SURE what you are posting is accurate and correct. If you find the code book hard to understand then it would be in your best interest to refrain from quoting it for a while.

Most DIY folks typically have no idea about codes, and will believe anything that someone named "electricman" posts. THAT is why we all corrected you in all these threads, not to be jerks or know-it-alls.
Your attitude did not help much either when we tried to show your mistakes.

Sorry pjb, we doubled. I was replying to electricman.

See, this is where I'm getting confused. My other thread discusses having a 20A breaker, 12/2 wire for a combination of outlets that are rated for 15A and 20A. I did not mention having lights fed with 14/2 branch off of that 12/2 circuit, which is is likely where the problem is.

My understanding of current and wire ratings might be off, which is why I love this forum before I get too far into projects. Is it not acceptable to run a 12/2 cable on a 20A breaker, then splice to a 14g wire running to a light? That's basically what I'm doing. I bought 1000' of 12/2 so that's not really a problem if all I need is to run the larger wire to make it right. I just didn't want to run 12/2 to a simple 65W light if 14/2 would work.

I was viewing it as 65W light would draw about half an amp, which would be fine on 14/2. a 20A circuit wouldn't put 20A through this branch wire since the branch wouldn't draw that much, so the 14 is OK. Are you guys saying that's not true because it can have 20A pulled through at the splice going to the receptacle and thus "melt" the 14g wire in the nut? Really not a big deal to run the bigger wire to the light.

And yes, I'll get a properly rated light for above the tub. I bought "Wiring a House" by Rex Cauldwell (2005, not recalled version) that I've been using for guidance but I haven't seen where it addressed splicing differeng gauges.

Final question for this then: to branch off a 20A circuit to lights, should I use 12/2 from the receptacle to the first light, then 14/2 between the additional lights, or is this still the same problem?

Here is a link that might be useful:

also, there's no wire nut except for the ground cable, I'm using the push in thing on the back of the receptacle.

Hoosierdoc,

The basic thing to remember in this case is that the circuit breaker is in place to protect the WIRING not the loads. Imagine that your lamp shorts out, all the 12ga wiring is fine. The breaker pops before the wiring heats up. The 14ga wiring is more vulnerable because it is thinner. If this wasn't a bathroom circuit requiring a 20amp circuit the solution would be to install a 15 amp breaker, thus derating the circuit. While in the real world the setup you have now is doable the code forbids it. There is a pretty fair safety margin built into the code. Imagine this however.... someone buys you home and wants to add additional whatevers to your circuit and they see the 14ga and junction off that with additional loads using 14 ga, now you may be over the safety margin.

All wire on a 20A breaker must be at least as large as #12 except for wire that came as part of a UL approved fixture.

And don't use the "push-in things on the back of the receptacle". They are crap and are the main cause of loose connections. Only use the screws and use wirenuts where needed.

Do a forum search for "backstab" for more discussions about how unreliable they are. This topic comes up frequently.

Maybe some one could explain to me the purpose of GFI protecting a light fixture. Not to be cute, I just don't know. When we are installing recessed cans in or close to showers or a bathtub, we use water proof cans with glass covers. We DON'T install standard cans and then try to cover the issue by GFI protecting the can.

Also, if we are running a 20 amp circuit, we wire everything on that circuit, including lights, with 12/2. However, if for example, we are wiring a dining room, all receptacles must be on a 20 amp circuit using 12/2. Lights in that same dining room can be on a seperate 15 amp circuit using 14/2.

There are two ways of wiring bath receptacles....

1. 20amp GFI circuit feeding ONLY receptacles in 2 baths

2. 20amp GFI circuit feeding receptacles and other loads in a single bath.

GFI not required for over tub light however if you are using #2 you end up with it depending on how you wire it up.

I assure you I know how to wire bathrooms. My question concerned protecting lights anywhere with GFCIs

Hmmmm.....ok, there is no valid reason to gfi lights

texasredhead, you and I have disagreed on gfcis before. In hoosierdoc's situation, it is convenient for him/her to run the light off the same circuit as the bathroom outlet which DOES have to be on a gfci.

Certainly there is no harm in a light being on a gfci. As I have pointed out, in countries like Australia (and, I think New Zealand) *all* outlets in new or modified work must be gfci. There is nothing wrong with enhancing safety. In a wet area, I think one could argue in favour of gfci protecting lighting, but that's just me. If there is no harm in it, why worry about it?

Hooiserdoc, do you get it now? It's not the load, but the circuit which dictates you must use 12/2 running to that light jbox. I understand your confusion but it's the code. Consider these two situations - 1) say the light appears upstream of the outlet. If that was the case, you would have a section of #14 in the circuit, which would be that weak link we were talking about.... 2) you or a future homeowner decides to add an outlet to the circuit, routing it from the light. Same situation. We must be able to assume that the whole of a 20amp circuit is 20 amp rated, right up to where the ul approved fixture branches off.

3) You or a future homeowner decide to replace the light fixture with a heat/lamp/heater combo, again assuming it's a 20a circuit. If you do it the right way, it will be, if you use #14, it won't.

Forget about logic or even technical issues for now, as you will. The reason for code and standards is so that we can rely on something being what we assume it is, if we make our own exceptions, and go under a bus or whatever, subsequent people have no idea what we've done.

I would like to add that just because code is code and you want to add something on a circuit that the proper checks be made within reason to make sure someone else didn't set a trap and run the last piece in the circuit smaller than what is required. The codes are there to protect from things such as this but it isn't perfect. I am sure there are tons of stories out there.

It is as simple as 20a. cir = 20a. wire (#12 minimum). 15a. cir. = 15a. wire (#14 minimum). If you choose not to have your light gfci protected, you can simply connect it before the gfci instead of on the load side. As far as back stabbing Gfci recepts, is this even possible. I don't think I could even buy one with back stabs on it if I wanted to. However they do come with screw tight clamps that don't require wrapping the wire around the screw. Although the wire is inserted from the back, sometimes into a hole behind the screw, the two are far from the same thing. In my opinion, back stab = friction connection, possibly loose/hot down the road, screw clamp/screw wrap = strong mechanical connection.

Do not use the simple push in connections son switches or receptacles.
Their long term reliability is not very good.
You will also not be able to use them with #12 wire on 20 amp circuits.
The hole was reduced in size many years ago so that only #14 fits (many problems occurred with #12 in the older back stab connections).

You can purchase receptacles that are back wired using a screw and pressure plate to attach the wire.
Back wire receptacles typically cost a little more.
Many GFCI receptacles are also designed this way.

OK, I'm using the wrong terminology again. The receptacles have the hole in the back with the tension screw. It's got the metal plate that grabs when you tighten the screw. Cauldwell's book recs against the simple push tension ones. Thanks for all the good help on this.