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So rewiring a bathroom because all the bathroom receptacles are connected and if any two of the bathrooms are using a blow dryer, circuit trips.

Master bath currently has lights and outlets both wired to that circuit shared with other bathrooms, so planning to swap out the master bath lights and outlets to a dedicated 20amp circuit. Oddly enough, wiring was done with 12-gauge wires so this should be fine.

I'm going to be dropping in 20 amp GFCI receptacle for the outlets. My question is, is it ok for the fan and the lights to be controlled by 15 amp switches when the outlet is 20 amps? Lights are on a dimmer as well. I think it's ok since load won't be high anyway, but wanted to confirm.

basement_diy
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2 Answers2

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TL;DR

I've seen something along the lines of this before:

It's ok by NEC 404.14. Sized for load being switched.

Pragmatically, it's probably fine since you shouldn't be drawing more than 15 amps through that switch.

If that fan ever malfunctions and draws more than 15 amps for an extended period of time then you have an active fire hazard.

How does a fan draw more than 15 amps, you ask? Well if the motor starts seizing up due to bad bearings then the amp draw will rise. Hopefully the motor dies before a fire starts I guess.

Also, can you guarantee me that someone in the future won't tap into that circuit and exceed the switch's rating? I think that an inspector would likely fail you.

Here is a discussion about putting receptacles on a switch which is inherently more dangerous since the load demand can easily vary.

20 amp Circuit, 15 amp switch that controls receptacles ok?

MonkeyZeus
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  • 'Will someone add wiring in the future' is a bit of a mess, because the world is full of a wide variety of idiots. – KMJ Oct 21 '22 at 17:37
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    @KMJ I typically go with "Make something idiot-proof, and they will build a better idiot." – MonkeyZeus Oct 21 '22 at 17:57
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Look at 404.14 for your code reference here.

To summarize, if you're controlling a receptacle then 404.14(F) requires you to use a 20A switch on a 20A circuit even if it's a 15A receptacle. For devices that are wired directly to the switch you can probably work under 404.14(A) and use a switch rated for the size of the load.

Check with the code to determine the specific limits if you're doing something unusual. For a few lights light or a fan below 15A, using the smaller switch is fine.

KMJ
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