Engine and electrical system grounding

01 Mar 2006 Engine and electrical system grounding

I mounted the forest of tabs ground onto the airframe. I ran one ground wire back to the batteries, and two ground wires from the engine to this single location. All the fat orange wire is AWG6 welding cable. It’s very flexible and easy to work with. All grounds will come to this point, with the exception of some very small local grounds, like position lights.

Here you can see the engine grounds. I have two of them, just in case something happens to one. If the engine loses ground, it will stop running. Electricity is as important as fuel to this engine.

Here is another shot of the engine ground. You can also see the starter and its cables.

Here is the schematic of the grounding system:

Notice that I don’t strictly follow the wise advice to have *everything* grounded to the same point. To do this with rear mounted batteries would require a lot more cables. So, I have a compromise, where just about everything grounds to the airframe at the same point, and is connected to the battery ground point with a fat cable. My overriding goal is to make sure that the engine computer and fuel pumps *never* stop. If these stop, the engine will not run.

I doubt that the fat cable from the single ground point in the cockpit back to the batteries is strictly needed. Many builders have reported that just grounding the batteries to the longeron in the back is sufficient.