uk_figs

Well Known Member
Friend
I bought the spruce avionics master relay to protect the avionics and an reviewing the documentation it appears that the avionics are connected when there is no power to the relays, this is to ensure a "fail-safe" condition in the event of a problem. This seems to mean that to disconnect the avionics I will have to power on the relays after the BATT master is turned on. and then power them off when I turn the avionics master switch on.
Has anyone else wired this into their panel and is this correct?
Thanks
 
Avionics Relay

you are right in that you hold power in the off position & the relay fails to power on. This assumes that your power feed come from the main bus that is fed via the main battery contactor. The avionics master sw needs to be a single pole double throw for this to work.
 
spuce relay

I assume therefore that the power line comes from upstream of the battery contactor controlled by the BATT/ALT master switch such that the relay is powered when the master is ON and the avionics master if OFF? (i.e the relay is not continuosly powered when the master is OFF)