Where to mount ground tabs block in -8 or -8A

Bubblehead · #1 11-28-2008, 08:14 PM

I am redoing some wiring in my -8 and have a rats nest of grounds going to a terminal block. I'm considering moving the ground wires to a new ground tabs block as described in The AeroElectric Connection. Because of the forward baggage compartment on the -8 it seems impractical to mount the block on the firewall.

So where do people mount their ground tabs block on an -8 or -8A? Pictures would be especially helpful. Did the location work well or would you put it somewhere else if you had it to do again?

Also, did you mount terminal blocks somewhere for avionics power or lighting power? If so, where did you mount them and did they work well there.

Thanks,

John

RatMan · #2 11-28-2008, 09:01 PM

I mounted a 24/24 ground block on the firewall, left lower corner (looking forward). It's from BandC specialties. Nothing new here, I copied someone else.

Bubblehead · #3 11-28-2008, 11:18 PM

Scott - that area is baggage area in my plane, which I use whenever my wife and I take a trip. What you've done sure makes wiring easier though, and does provide a good place for the battery!

I like where you put the wiring blocks a lot. It makes them easy to get to and a short wire run from the aux electrical panel on the right side of the plane.

Ratman - if I understand you correctly, the ground tabs are above the boost pump?

Another question for both of you - there does not seem to be many things to ground on the firewall side.

rv8ch · #4 11-29-2008, 08:51 AM

Here's where I (originally) put mine.

http://www.rv8.ch/engine-and-electri...tem-grounding/

Probably not the best place, it seems. Most of my ground wires are up behind the panel, so I ended up running a bunch of ground wires down to this "forest of tabs". I'll probably end up moving it.

Update: I will move it, not 100% sure where yet.

Bubblehead · #5 11-29-2008, 11:09 AM

Mickey,

It looks like you're using the area forward of the right gear tower for wiring and perhaps the battery, much like Scott is doing. Right now mine is set up for baggage but I may have to change that.

Thanks for the photo. It gives me an option.

John

Bubblehead · #6 11-29-2008, 03:39 PM

The following was done with the ground cable disconnected from the battery.

I spent the afternoon under the panel trying to straighten out the mess and figure out what the terminal blocks are for. It turns out there are three separate blocks. Two are hooked together and are grounded to the airframe. The third terminal strip is confusing me.

I figured that the third strip would be an avionics buss but to verify that I hooked up my ohm meter between the main buss and the terminal strip and found that I had continuity between the two regardless of the position of the avionics master switch!

That seems to mean that anytime there is power to the main buss there is power to this other small buss, which means whatever loads are attached to the small buss are hot when the master goes on. This could also mean these loads and their wiring are not protected by a circuit breaker or fuse!

The wires attached to the small buss disappear into the rats nest and a wire bundle so I was not able to trace them.

Does anyone have any idea what loads might be attached to this small buss?

I took some pictures of the terminal strips that I'll post later tonight or tomorrow.

RatMan · #7 11-29-2008, 03:41 PM

Quote:

Originally Posted by Bubblehead

Ratman - if I understand you correctly, the ground tabs are above the boost pump?

Another question for both of you - there does not seem to be many things to ground on the firewall side.

No, it's exactly the same as Scott's except it's on the opposite side of the aircraft. Scott's is on the right side, mine is on the left. His is MUCH easier to get to and I almost did the same thing but I didn't want to give up the storage. (edit: John, I noticed you have an IO-360 so yes, it would be above your boost pump on the firewall. I have an O-360 so my boost pump is farther back near the gear tower.)

There isn't a lot on the front of the firewall to ground unless you are using electronic sensors like the ones Dynon uses. I might have 5 or 6 sensors grounded there without counting. I could have grounded them to the firewall but just seemed easier and neater to use the ground block.

Scott, how did you label the shrink tubing? I just spoke with Stein about this but his machine is a bit to expensive for me. 99.9% of my wiring is done but that is the way to go! Really nice

Bubblehead · #8 11-30-2008, 02:14 PM

Well I made a breakthrough on my understanding today. I spent a couple of hours at the hanger, pulled the instrument panel out part way, and was able to really figure out what the three terminal strips mounted on the right gear tower do.

7 posts are for ground wires
3 posts are for panel lighting
3 posts are for the instrument panel AND the starter solenoid circuit.

The third one is the way Vans schematic shows it.

Once I figured out how it was wired things got easier. I was able to straighten out a lot of wires. I don't think I'll change the location of the ground terminal strip, but I will change the wire routing to the engine compartment for alternator and magneto wires.

Thanks to those who posted info, ideas and pictures. Seeing what you guys have done helped a lot.

Mike S · #9 12-01-2008, 09:58 AM

You can make up paper labels on the computer, and use clear heat shrink over them.

Cheap, simple, easy, and look good.

RatMan · #10 12-01-2008, 10:09 PM

Quote:

Originally Posted by Mike S

You can make up paper labels on the computer, and use clear heat shrink over them.

Cheap, simple, easy, and look good.

Yea, that's exactly how I did mine and they're OK but...Scott's are the same as Stein uses on their harnesses and they look great and are easier to read.

If I do it again I'd beg Stein to print a bunch for me. If that didn't work I would remind him that I aint broke yet! That would drive him nuts.