If any of you guys out there tend toward OCD and are currently wiring your plane, here's a heads-up.
I probably know too much (or maybe not enough) for my own good about electrical stuff, including issues like electrical noise & ground loops. So when I created the wiring harnesses for my RV-7 a couple of years ago, I tried to make sure I avoided ground-related issues by carefully routing grounds *exactly* where they should be according to the avionics documentation, and making my best educated guess when I couldn't find any good documentation.
Well, I laid a couple of mines, & didn't step on them until I installed the instruments to do a test powerup, prior to closing out the fuselage. The intercom wouldn't power up, and neither would my Anderson engine monitor. After spending a couple of days digging through my extensive (but not very well done) notes, I found the sources of my problems.
The intercom has a 'floating' chassis, and you're directed to run the ground wire to the radio. I did this; running the ground to the power ground in the GNS430's tray. I also thought it would be smart to ground the Anderson monitor to the main ground point in the EC-2, so I tied it to pins 19 & 37, which are then grounded to the engine block. (I documented the power connections well, but the ground side...not so much.)
So on my 1st real power-up test of the system, not wanting to put multiple high dollar instruments at risk, I only powered or installed a single instrument at a time. Anyone see the mines yet?
Charlie