MGL Avionics User Forum

I am installing a string of 3 ECBs. I think I am clear on everything except the PWR+ pin on the D9 connector.

The manual says " Note: Supply current for the ECB will be taken either from the breaker input terminal or the supply pin 4 on the D9 connector depending on which voltage is the higher."

This confuses me. If the wire to D9 pin 4 comes from the Master bus, just like the main breaker input terminal, then they are electrically identical. Why would one be higher than the other?

So where should the D9 Pin4 be wired from and what fuse should be used?

I am supplying each breaker input terminal post via 16GA wire with a fuse appropriate to the max load on that specific ECB. Should I do the same for D9 pin 4?

Loman,

The Pin 4 and high current inputs are likely diode-isolated, so if, for example the high-current terminal (referred to from herein as HC) voltage is higher than Pin 4's voltage, it "overpowers" it, and because there's a diode to prevent reverse current flow, the pin 4's voltage will never equalize to the higher voltage of the HC input.

All of that said, unless you would like the ECB's computer to have power applied to it before the breakers themselves have the potential to carry power, it is probably best to just leave pin 4 disconnected.

Adam