Ground to frame

[Peter_SE]

I ended up grounding the battery to the frame and then ground all components to the same point in the frame behind the firewall.

Thanks all!

[jonstark]

I ended up grounding the battery to the frame and then ground all components to the same point in the frame behind the firewall.

Thanks all!

I recommend that you separate any audio or signal grounds onto their own stud or buss.

Jon

[Peter_SE]

Naah!!....i changed my mind and will ground the way that Paul suggest. The only pint where B- will ground the fram is the firewall passthrough bolt.

Or

I´m also thinking of isolating the passthrough bolt from the frame...

Hmm..!

[PaulSS]

I don't think you want to isolate the pass-through bolt as that will ground the firewall (and frame) to the central ground and, then, back to the battery.

I'm going to use one of those 'forest of tabs' ground buses. This will be bolted to the firewall. The big stuff, like the engine grounds and battery ground will go to the big pass-through bolt and everything else will just attach to the tabs.

Forest of tabs

[PaulSS]

I've done a bit more reading on the subject of 'star' ground systems and I am even more convinced than I was before about using this type of setup. I thought the 'forest of tabs' bus was connected to the firewall but I was wrong and it should be isolated and then wired to the pass through bolt with a single wire. The pass through bolt is bolted to the firewall to ensure it makes contact there. I was also thinking of grounding the battery to the airframe using a tab near the battery but this, apparently, would be another ground return and potentially a ground loop source.....so the only wire going to the battery negative will be the one from the pass through bolt.

I'm still waiting and dreaming and obviously just have 'book learning' on this subject but it certainly seems the way to go with modern avionics.

This is my final basic system design (well, it's not mine at all, just re-drawn )