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Grounding: Local or All in One Place?

rockitdoc

Well Known Member
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So, what's the consensus:

1. Locally ground everything at the location where the electrical piece lives, ie, the fuel pump at the mount as shown in the plans, or

2. Run all ground wires to a central grounding block behind the panel or somewhere else convenient to reach.

What say you?
 
Neither.

Ground locally where doing so won't introduce noise into the system; use a return ground where it might. Doing the former saves weight, cost, and valuable space through sometimes-crowded wiring grommets; the reasons for the latter are self-explanatory. For me that meant only avionics are on a dedicated ground buss at the panel. Most everything else is local.
 
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Just me

I think this best practice is changing with the change to LEDs and all glass systems. The days of old power supplies, strobes and high current lights are fast going away. I think the days of having to run ground returns are also going away. I think the newer technology does not put as much noise back on the power lines, and they consume much less power.

Just for me, my G3X electronics grounds are following the Garmin recommendations. Everything else is being grounded locally. I don't think I will be having a need for a "forest of tabs" like the old days.
 
I think this best practice is changing with the change to LEDs and all glass systems. The days of old power supplies, strobes and high current lights are fast going away. I think the days of having to run ground returns are also going away. I think the newer technology does not put as much noise back on the power lines, and they consume much less power.

I offer that LED strobes, nav and Landing Lights can be the source of a lot of RFI if not properly installed. For LED Nav/Strobes I run three conductor #20 shielded wire, the shield providing the ground for the Nav/Strobes and grounded only at the firewall. For everything else in the wing I run one ground wire to the firewall - that one wire having pigtails to feed the other components.

I dislike local airframe grounds as I’ve chased problems in other planes caused by local grounds going bad (corrosion, etc.).

Carl
 
I recommend running most grounds back to a central location, with that location then bonded/grounded to the engine block. While there are a few things that ground locally directly to the engine (starter, alternator, etc.), any items that are remote should I believe be run back to a ground block.

While it's true that our LED lighting systems don't draw as much current, there are still a lot of high current electrical loads that haven't changed, such as the fuel boost pump, pitot heat, vent fans, etc. And some of today's electronics are very sensitive to EMF interference, particularly the magnetometer. And radios haven't changed either in their sensitivity to noise. So I ran all of my grounds back to a pair of ground blocks, which were then bonded to the engine block.

You are of course free to build your aircraft as you see fit. But should even one of those locally grounded devices cause you noise issues, be prepared to likely spend hours searching for the source of your problems.

Just the opinion of a professional electrical engineer with a BS degree in Electronics Engineering.
 
Home Run

I learned a lesson last night, I installed new LED Nav / Strobe lights and the noise in the headset was brutal, so I ran a ground all the way back to the firewall instead of the short wingtip pigtail chassis ground wire and BLAM! problem fixed.
 
I learned a lesson last night, I installed new LED Nav / Strobe lights and the noise in the headset was brutal, so I ran a ground all the way back to the firewall instead of the short wingtip pigtail chassis ground wire and BLAM! problem fixed.

This is the best way to do LED strobes. I also do it with remote magnetometers. Shielded cable in both cases.
 
Local grounds make global problems. They also make avionics shops a lotta money.

Take extra care with your wiring and you'll enjoy flying instead of chasing problems.

YMMV!
 

Note this article is: Tony Bingelis (originally published in EAA Sport Aviation, May 1994). No glass panels at that time to deal with, and not much electrical other than radios, lights and perhaps flaps. While the theory is correct, I wouldn't recommend this method with today's electronic systems.

Just the ramblings of a professional electrical engineer. :)
 
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