hmmm
hmmm
xformer wrote:
Is it permissible to install a 15 ampere rated switch on a branch circuit protected by a 20 ampere overcurrent protective device? A 15A wall switch installed for a ceiling fan on a 20A branch circuit is an example. I sometimes get referred to 110.9, but the device is not designed to interrupt current at fault levels. So my conclusion is Yes it is permissible. Am I wrong or right?
Roger writes: You are right, 110.9 is not really applicable, the article and section would be 404.14 and yes, it is allowed.
That just didn't sound right to me, so I looked around in the NEC to see if I could prove it inappropriate, and I really couldn't find a protection requirement for the snap-switch, only application criteria, like being rated for the load.
So it seems that there would be the limitation that the fan/light could only carry 80% of 15 amps for a motor load, or 12 amps. And I would bet that's probably enough for most fans.
Is it common practice to wire a 15-amp switch using #12AWG wire? Are the 20A switches that much more expensive than the 15A? And if the load is less than 12 amps, why not use a 15 amp breaker?
Please understand guys that I'm a practicing engineer with an electrician's license, so I'm not well versed in residential trade practices. I would certainly have used a 20A snap-switch, just based on the 20A upstream breaker. Although I agree that the Code permits usage of the 15 amp switch.
JM
