On Saturday, September 14, 2019 at 11:13:17 AM UTC-4, Wade Gattett wrote:
Two 3-way switches controlling a big Hunter Original ceiling fan on a 20
amp circuit worked fine for 33 years of occasional use. A week or two
back, they quit working properly...both had to be "on" for the fan to run.

I decided to replace both switches and picked up two 20A Leviton 3-ways.
When I pulled the old switches, they were slightly different models- but
both were marked "Slater 15 amp".

One of them had what looked like the beginnings of some mild surface
corrosion on its metal support bracket- though I guess it could have
just been a scuzzy-looking mill finish. The other one was bright and
looked fine. Unfortunately, I didn't test them and just tossed them out.

With the new switches installed, the fan is working right.

At the local Home Depot, the 20A switches were twice the cost of the 15A
ones. I'm thinking if the price difference was the same 33 years ago,
maybe that's why the electrical sub used them.

We ended up having a lot of problems with the general contractor for the
room addition where the fan was installed. What do they say about apples
not falling far from the tree?

So- is it OK to use a 15A switch on a 20A circuit? Could that have had
anything to do with the switch failure? Or are Slater switches not so hot?

--
When the people find they can vote themselves money, that will herald
the end of the republic.
- Benjamin Franklin



I believe the answer is that the switch is sized to the load, not the
breaker. So 15A is OK. It's hard to imagine a fault condition where
a 15A switch is going to create a safety hazard in that application.
As to whether a 15A switch contributed to your switch failure, I'd say
yes and no, mostly no. Your small fan load is nowhere near the limit
of either a 15A or 20A switch. But a 20A switch may be built a bit
heftier, might take more openings and closing, etc than a 15A one,
so a 20A one might have lasted longer. There are also differences
among 15A switches, ie a cheap chinese one or a better spec grade one,
(probably from China too