B&C Ground Block Grounding
 

Hi Guy's

I've decided to mount my B&C Ground Block behind my panel but I'm unsure if it would be OK to run the Ground to a separate bolt on the firewall rather then back to the block itself? Can anyone see a issue doing this?


Many Thanks
Gibbo

The block should have a good electrical connection (strap/wire) directly back to the battery.

Your plane is a little different geometry than my 7, but I mounted the block to the aft FW and used a brass through bolt to a ground strap directly to the battery post on the forward (engine) side. This covered the chassis and battery ground.

Grounding
 

is best done like Bill suggests, but common sense needs apply when you evaluate your particular situation. Battery forward? Then ground to the Battery. If Battery aft there is nothing wrong with using the airframe for ground return to avoid running another heavy wire.

The FOT can be directly grounded to the firewall. No matter where you ground the FOT you avoid ground loops by using it exclusively, when possible, for grounding, which keeps the potential between things under control.

Thanks Bill & longline, I made the decision knowing that the favorable location is on the firewall with the ground wire directly to the battery (up Front) but I wasn't overly happy with the FOT behind the pedals and the next best spot was over the left side forward of the fuel pump on the firewall but in that location I would require the same if not a longer wire run as to where I have it located behind that panel. It won't be an issue running the ground from this location but I guess the question was whether or not grounding to the a firewall bolt away from the FOT would be a issue.

Cheers Gibbo

If you look in the book (you do have the book, right?) Bob details the primary FOT on the back of the firewall, as others describe (for all the higher current, noisy ground returns), and an avionics ground bus near the instrument panel. In that case, the avionics ground would have its ground wire run back to the firewall.

If you're grounding everything at the instrument panel, then 'float' the FOT & run a heavy ground wire(s) back to your firewall ground feedthrough. The whole idea is to keep your avionics grounds away from a situation where they are 'between' other items' ground connections and the battery negative.

BTW, if you're using high quality PIDG terminals, the shrink wrap is redundant. Looks pretty, though. :-)

Charlie

Thanks Charlie :)