According to the EFIS Main Harness installation, there is a ground wire that attaches all the shielded wires in the harness and is connected to the "CASE GROUND SCREW." On the drawing it states a
4" wire pigtail to the Case Ground Screw.
Does that mean that this wire can and should be only 4" long or can it be longer???
Thanks.
Thers is a short black wire coming out of the harness, this should be connected to the EFIS case ground screw along with a wire to the airframe ground.
Rob Hickman
Advanced Flight Systems Inc.
Is there also a short ground wire in the EM harness as well? I did hook up the short one to case ground on the EFIS along with running 18awg wires from aircraft ground to both my EFIS and EM. Just don't remember seeing one for the EM.
Thanks.
No, the 22AGW black wire provides the ground for the shields of those wires.
In looking at the connectivity for many of the RS-232 devices (i.e. page 67 in the manual) have dedicated ground lines for each serial port. Doesn't this create a ground loop with the master ground?
No it does not. Always ground just one end of the shield. You should connect the Serial Ground to either a matching serial ground on the other RS-232 device, or if it doesn't have one, tie it to the shield on one end.
I agree with your statement about grounding one end of the shield, which is traditional for RS-232. However, the manual states something different. For example on page 67, it shows pin 21 on the EFIS being connected to pin 3 on the SL-30. This would create a ground loop. I would think that with each device connected to the forest of tabs ground on the firewall, these individual grounds would not be needed other than to tie one side of the shield.Originally Posted by Trevor Conroy
You could do it either way. Many Garmin manuals also show connecting the shield to ground at both ends. It is not as big of an issue for RS-232 or ARINC wires, but crucial for audio wires.
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