common ground block

[david.perl]

Im finishing my wings and putting some electrical bits in them. Whats the advantage of running individual ground cables for each item back to a common ground block as opposed to using the airframe as the ground?

[cfiidon]

David,

The answer to your question is: "It depends on what it is."

My thoughts are that all avionics (anything with a signal or data on it) should be grounded to a common ground block.

Non avionics items like lights, pitot heater (items with a straight dc power line), etc can simply use an airframe ground.

Strobe systems, and the wires for those are typically a shielded bundle and that can be terminated to local airframe ground at one or both ends.

There can be exceptions to this, and that is where the manufacturers recommendation or empirical evidence comes in.

Don

[N941WR]

In my plane I pulled all the grounds back to the common ground block, which was bolted through the firewall to a matching block on the other side. The only exception was the strobe grounds and landing and position lights.

The landing and position lights are grounded on a rib, using a plate nut.

The strobes are a different story. I found that I could hear the strobes in the headsets during testing. My solution was to bring all the grounds and the shielding wires back to a ground (Platenut) which I installed right next to the power pack.

The shielding on the strobe wires was clipped at the strobe and continued on to the strobe ground, next to the power supply, as mentioned above. Do not ground the shield on both ends.

I do not believe this is required, if you have the new style LED strobe lights.

[fehdxl]

Originally Posted by cfiidon

...There can be exceptions to this, and that is where the manufacturers recommendation...

Here's an example: http://www.vansairforce.com/communit...ad.php?t=80132

-Jim