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Material for Main Bus

L

lr172

Well Known Member
I am planning my wiring for my RV-6A. I am curious what is recommended for the main bus. I was thinking of a copper bar similar to the ground bus. How are most people mounting this to keep it insulated from the airframe? Is there a more preferred method?

Thanks,

Larry
 
Copper's conductivity is 7 times better than brass. I used stock from B&C as shown below:

BKR_0001.JPG
 
I am also concerned about protecting the positive power circuit from shorting out and while I would use the copper buss bar for the ground side of the switches (I'm using a VPX), I might just daisy chain the positive side and insulate the connections with liquid electrical tape. I've heard some horror stories about accidental shorts....
 
That makes sense. I had arranged my breakers in a more vertical pattern, requiring wires. Maybe I will rearrange them horizontally along the bottom as you have done here. The simplifies things a bit.
 
Mark Dickens said:
I am also concerned about protecting the positive power circuit from shorting out and while I would use the copper buss bar for the ground side of the switches (I'm using a VPX), I might just daisy chain the positive side and insulate the connections with liquid electrical tape. I've heard some horror stories about accidental shorts....
Click to expand...

I considered daisy chaining, but you must then size each jumper for the max buss draw or make them progressively larger as you go down the chain. I figured a remotely mounted buss would be easier, especially for tieing in the alt B lead and Batt cable. Now thinking of arranging horizontally for simplicity.

Larry
 
Mark Dickens said:
I am also concerned about protecting the positive power circuit from shorting out and while I would use the copper buss bar for the ground side of the switches (I'm using a VPX), I might just daisy chain the positive side and insulate the connections with liquid electrical tape. I've heard some horror stories about accidental shorts....
Click to expand...

Every additional connection adds resistance regardless of how well it is made. It also introduces a point of failure. A solid copper buss is very efficient. Just something to think about.
 
Alternative

On the other hand, if you use a fuse block, the fuse block is the bus. If you need more than one fuse block, a short jumper to the other fuse block extends the bus.
 
Mark Dickens said:
I am also concerned about protecting the positive power circuit from shorting out and while I would use the copper buss bar for the ground side of the switches (I'm using a VPX), I might just daisy chain the positive side and insulate the connections with liquid electrical tape. I've heard some horror stories about accidental shorts....
Click to expand...

A removable (or flex out of the way) flap of baffle material could provide a good cover to stop those evil dropped items that create those accidental shorts...:)
 
Rick_A said:
On the other hand, if you use a fuse block, the fuse block is the bus. If you need more than one fuse block, a short jumper to the other fuse block extends the bus.
Click to expand...

Great point. With a little care and some creative fabrication, you can also connect the fuse blocks with copper strapping. This eliminates two crimp connections per block. Getting a little obsessive, but I chased an electrical issue for a long time. I finally reworked the entire system eliminated as many crimp connections and reduced wire run lengths that I could find. Cured....
You can protect the straps with heat shrink or silicon tape if you concerned about accidental fob shorts. My fuse blocks are mounted facing down located on a panel I fabricated between the ribs between the firewall and the first bulkhead.
Not easy to get to the fuses, but I have never needed to, and probably won't.(Entire different tropic)
 
I covered my buss bars with large diameter heat shrink, slit down the back to get it around the breaker terminals; held on with tie wraps. Just in case I manage to drop or lose a screw at exactly the wrong place...
 
I used two fuse blocks in the first RV (8A). They worked but were a pain everytime I wanted to do anything, and unless you have these things on the front of the panel they are not accessible in flight. Hard to figure out what is going on if you can?t see if a fuse is popped or not.

Second RV I used standard breakers (RV-10). Far more practical in operation.

Current build (RV-8) will also use breakers. Each panel wing (the part that stays in the airplane) has six breakers, Avionics 1 on the left and Avionics 2 on the right. Non-vital loads are on the side switch panel. Only three breakers on the panel but they come out with the panel (2 D connectors, 1 molex, three antenna leads and the SkyView D connectors and the panel is out on the bench).

Never a fan of the old Cessna style copper buss bars. While I?m sure a lot of people use then just fine, they always look to me like an accident waiting to happen. I have a #10 wire from the left or right battery mounted Avionics relays (small 30 cubes) that goes out in pigtails for the power into each breaker. Recommend not daisy chaining power to breakers.

Take the various opinions then do what you want to do.

Carl
 
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