"CL (dnoyeB) Gilbert" wrote in message
...
Bud wrote:
As HorneTD has said in a number of threads, the NEC requires the
switch
has to be large enough for the load. If a switch is connected to a
light
fixture, it would be a little difficult to lamp it at over 1200W,
the
rating for a 10A switch. Going through my box of salvaged switches
I
found several with a 10A 120V rating. The NEC is a pragmatic code;
if
there are problems the code is changed to deal with them.

Bud--



And this is why we have Murphy's Law. You don't size the switch to
the
intended load. You size the switch so it can't cause a fire. If
that
fixture endures a resistive short, and its passing 15A, not enough
to
blow the breaker, but too much for the switch, you have a serious
problem. So I guess NEC needs an updating wrt/ Murphy's Law.


A look at the Leviton and Cooper product lineups show all residential
switches to be rated at 15 or 20 A. From the Leviton technical
reference, AC/DC switches can be used on motor loads that are 50% of
the switch rating (80% for AC only switches) . To qualify as a motor
rated switch, an AC switch is tested at 6X the full load motor HP
rating current, 10X for DC, and goes through 50 make/break cycles in
addition to the normal overload endurance and heating tests

Your example of a 15A resistive short is 1800 watts. I would imagine
governing bodies view the chance of a 15A switch made of fire
retardant materials, installed in a box, and running a few amps over
it's rating starting a fire is insignificant compared to the short
itself.