Avionics Master: Do you need a relay or a switch?
 

I know some folks don't like em, but I've decided I want an avionics master. My question is to the folks who've wired one, do you need a relay or will a switch do the job? I'm calculating my total current to be around 15 amps. So can I get by with a switch?

I used a Potter & Brumfield circuit breaker with toggle, # W31X2M1G35. Look on page 428 of Aircraft Spruce. Thats what was in my Cherokee Six for a avionics master no relay required.

Yes
 

Hi Steve,
It's a wise move to protect your avionics from startup voltage surges. We used the same circuit-breaker switch and ran a wire over to the avionics circuit breakers which were on their own buss bar, plus a spare (VOR maybe). We placed the avionics circuit breakers in the same order as they were stacked vertically.

Regards,

I used a double throw switch and wired my starter switch through the back side so that the starter is inop when the av master is on. Some people don't like this because, if the engine quits in flight, you have to remember to turn off the avionics to restart. My answer to this is; if the engine quits in flight, the prop should continue to windmill and you don't need the starter. If the prop does not windmill, you have other problems and the starter won't help anyway.

DPST switch...
 

You can use a double pole switch and wire both contacts in parallel for a bit more reliability...

Costs very little more, and guards against contact failure.

Make sure a single contact can handle (is rated for) the current load, 15 Amps in your case.

gil in Tucson

Actually I used a DPDT. I just didn't mention it. Sorry.

New Product at ACS - AVMaster Relay
 

I just saw this today in an email from AVWEB - looks pretty interesting. I might go for this myself:http://www.aircraftspruce.com/catalo...dcopy&kw=Flash

Switches fail...
 

If you are going to use a switch, you might think about wiring two in parallel so that when the first fails you can still continue with the second.

Kent

I'm with Kent. I'll take 2 flea market switches over just about any single switch, regardless of it's pedigree.

It turns out that most of the stuff I want to protect with an Avionics Master are also on my Essential Bus!! That means that if my Avionics switch fails, by Essential Bus switch will turn them on.