Bathroom lights shared with 20 amp GFCI

Polecatt2 · 03-20-2011, 01:52 PM

Hello,

After reading through hundreds of posts looking for some help with my scenario I have learned a lot but not quite enough to get my question answered so here it is!

I am building out a new bathroom in a basement reno and need some clarity on the electrical. For any local code implications, I am in Toronto / Canada.

I have run 12/2 on a 20 amp breaker from the service panel to a GFCI and would like to know if I can run 14/2 on the load side to a switch then 14/2 to a recessed light in the shower then on to the vanity light. There will also be a main light on a separate switch fed from the panel on a 15amp 14/2 and shared with receptacles in an adjacent room.

Basically I'm wondering if the 2 lights that would typically pull 1-2 amps only can run on a 20 amp circuit after the last (only) 20 amp device. Does the entire branch circuit and every device (switch, light fixture, receptacle) on it need to be rated for 20 amps or only the portion of the circuit that could potentially pull that much current? I have read that the code supports 15 amp receptacles on 20 amp branch circuits because they wouldn't be able to pull 20 amps.

One other point of clarity I'll add... Does how the devices are wired have any impact on this (passthrough vs pigtail)?

Any help would be appreciated!! Thanks

oleguy74 · 03-20-2011, 02:38 PM

all wireing must be capable of carring the current of the breaker rating.in a bathroom,if the 20 amp ckt stay's in the bath,lights can run off the bath ckt.

Polecatt2 · 03-20-2011, 02:51 PM

Thanks for the quick reply! the 20 amp circuit will stay in the bathroom. Is there any differentiation between the circuit wiring and the switches / fixtures? In my scenario do I need to have a 20 amp switch and light fixtures that can support 20 amps for the shower and vanity?

oleguy74 · 03-20-2011, 03:05 PM

no. not necessary.

Polecatt2 · 03-20-2011, 11:09 PM

This is great. Seems simple. I understand that code says all wiring on a 20a circuit must be 12g and I will make sure I run the wire this way.

Can anyone comment on the way that electricity will actually flow in my scenario? I am unclear how different fixtures on the same branch circuit impact eachother.

Again here is my setup. 20a breaker - 12/2 - 20a GFCI duplex outlet - 12/2 - 15a single pole switch - 12/2 - 4" can in shower (50W max) - 12/2 - vanity light (100W max).

If I were to plug and run both a hair dryer, and a curling iron into the outlet drawing 16 amps would this have any impact at all on anything else in this circuit? What if I had put the switch and lights on a pigtail on the line side of the GFCI outlet?