14 gauge wire on 20A breaker

A contractor recently remodelled our master bathroom, and ran a dedicated “20A” circuit as required (by Broan) for the new bathroom heater / vent / fan combo unit. He installed a 20A breaker, but ran 14 gauge wire.

The Broan model has a 1500watt heater element, but says total draw is 14amps. Regardless of the fact that this is a dedicated circuit within the current capacity of 14 gauge wires, this really is unacceptable to put 14 gauge on a 20A breaker, right? Total run length from breaker panel is about 70 feet.

Recommendations, please? Should I require the wire to be replaced with 12 gauge?


Yes, it is incorrect. Run the new wire.

Breakers and conductors should be sized for 125% of any continuous load.

Edit: To clarify, the conductor sizing at 125% (#12, 20 amp) will mean the breaker will need to be the 20 amp he installed. Always check manufacturer specs to be sure.

Continuous? How long do you spend in the bathroom??


According to what we are taught #14 AWG copper is fine for 20amp.
But no smaller than this.
#12 is usually used typically.
Now here there is a exception and that is if the it unusually long say (130 feet) or in the Kitchen.

I don’t know anything about the CEC, but for the NEC…#14 is not to exceed 15 amp protection in this application.


That is correct!
I do not know where Tom is from so I just want to point out our side.
That is why I said HERE.

Should it be replaced, Yes
Should you do it? No the contractor made the mistake try to get them to fix it, which you may or may not have success with.
Was the contractor a Licensed Electrician?

Installation was bogus. If a 20 amp breaker was specified, the manufacturer likely expected the draw to occasionally exceed the next smaller breaker (15 amp).

20 amperes = 12 gauge

Unless it is an alumiinum cable, then #10 is required :wink:

Wow, thanks for the quick feedback.

Yes, this was a licensed contractor in the state of Minnesota.

What I have seen so far would imply this guy has a bunch of problems:

A junction box was sealed into a wall with no access (behind sheetrock).
No staples were used on the junction box - cables were left dangling.
A timer was installed on the 1500W bathroom heater, but the timer was only rated for 1200W.
One switch terminal had a 12 gauge wire inserted straight and tighted under the screw head (not wrapped around the screw terminal).

I don’t think it’s appropriate to burn the company here, but my recommendation to the general contractor is to stop doing business with this bozo.

I only say continuous because of the heater. If it is left on accidentally that would be continuous for me and it is the high amperage load on the circuit.

And for your information, with five kids, the older I get the longer I stay in there! It’s peaceful! :-D;)

Yes this needs to be corrected ASAP. What can happen I call the toaster over effect, where the wire between the breaker and the appliance “Could” heat up like a toaster oven coil. In fact not sure about your area, but here every new circuit should technically have a permit pulled for it. Around here they have what they call Post Card Permits, where as a Master Electrician we can provide our own permits and inspections for up to 10 devices. Over 10 a regular permit with a county inspection must be pulled.


Technically it is whatever your temperature rating allowed on the wire, breaker and appliance. This NEC app self explains this https://itunes.apple.com/us/app/a-nec-quick-reference/id474647605?mt=8 .