F

Flying Scotsman

Well Known Member
Quick question...doing the wiring harness for my Garmin audio panel, 430W and SL-40 stack (thanks to Stein for providing some really nice harnesses with each radio!). Shields are grounded, per instructions, at the audio panel's chassis ground.

The panel is out getting powdercoated and should be ready tomorrow (Yay!).

So...do I need to make sure there is some electrical connectivity between the radio stack/racks to the panel and thus to airframe ground for this to be correct? I.e., remove some of the powdercoat at screw or mounting bracket contact points? Would not ensuring this path essentially mean these shield grounds are, well, ungrounded and thus ineffective?

I'm guessing the panel will come back completely powdercoated and thus, if nothing is done, would be insulated from airframe ground...

Sorry if this is a silly question...

TIA!

Steve
 
The audio panel is internally grounded from the ground wire running to the ground block. No need to worry about a chassis ground at the attach points.
 
From and EMI/EMC perspective, it is a good idea to assure that your panel has a good connection to ground at the mounting screws. As previously posted, the chassis of the radios are grounded through a separate connection and it is not neccessary to ground the trays. When I had my previous panel powder coated, I sanded the coating off around each one of the mounting screws around the perimeter on the back side of the panel.
Bill
 
These two answers seem to be in direct opposition to each other.

I'd rather not uglify a nice powdercoat job, unless it's really needed...first answer says it's not needed, second says it is.

Do we have a tiebreaker? :)
 
Yes, you need to provide a path from the stack to the panel. The 430 shields are terminated to a block on the back of the tray.
 
Trevor778 said:
Yes, you need to provide a path from the stack to the panel. The 430 shields are terminated to a block on the back of the tray.
Click to expand...

You should provide a path to ground from the stack by connecting a wire from a grounding point on one of the trays to the airframe, preferably at the point where all of your ground wires are are terminated and connected to battery ground.
 
You don't have to make the powder coat ugly. You can either make or buy a tool that is designed to remove paint from around holes to facilitate a ground point. It is a small circular scotch brite pad that is around .5' in diameter, with a guide in the middle to center it on the hole. The paint removal is done only on the back of the panel so that it will come in good contact with the mounting surface.
In all likelyhood you can use Dave Cole's suggestion and probably get away with it. I re-did a Piper Cherokee a year ago by replacing the entire panel with a solid .125 sheet, and powder coated the panel and then removed the paint as I described. I have not seen any issues thusfar.
 
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