I think I know the answer to this but I would like some other opinions:

I am trying to select some sealed DC rated miniature rocker switches to
be used as manual overrides for my remote digital DC lighting system.
Real estate at the nav station is limited so the circuit is SMT and
designed to be very small. Size of the switches is important. DC
switching is harder on the contacts than AC because of arcing but these
switches will be used only to operate navigation lights should the
digital system fail so they will cycle much less than 30-40 times a year
and the majority of that will be from "Remote" to "Off" when there is no
load anyway. Maximum load on any circuit will be about 6 amps with a
maximum inrush load of possibly 12 amps.

It seems that only one in ten miniature rockers is DC rated and those
that are are 3 to 4 times as expensive. Almost all DC rated rockers are
"standard" size. Evidently to give the contacts more thermal mass.

In the course of my search I was surprised to find that the rockers on
Cessna, Beachcraft and many other light aircraft are not DC rated. The
reasoning being that a typical landing light switch might be operated at
most 2-3,000 times over 10 years so derating a 25,000 cycle AC rated
switch by 90% is acceptable to the FAA.

So, unless someone comes up with a good reason not to, I am going to use
15A@120VAC switches.


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
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