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B&C buss problems

M

MWDG3

Member
Hello Van's members.

Recently a local RV9A owner was having problems with his tach and Trutrak autopilot falling off line simultaneously. I noticed he had what I now know to be a B&C 20 position bus. It's used as an essential bus supplying mostly avionics. A separate smaller B&C is labeled "main" supplying mostly lighting. In the past we installed a new radio stack and used panel mount breakers. So I installed another breaker for the a/p and put the tach on a fuse from the new avionics bus. Both work great now. Owner has no schematics of original installation.

Any members here experience issues with B&C bus blocks?

RV9%20bus_zpso98fplmd.jpg
 
Yes.

I have used them for many years in multiple airplanes without a problem. I have seen the crimps on the end of the wires cause a problem. Fuseblocks are pretty reliable. It's what's in most of our cars.

Vic
 
Most of his failures were in the air, a few while taxing to takeoff. I thought it odd two unrelated circuits failing at once. Thank you for the input.

Edited to add, power off reset always restarted both units.
 
Last edited:
MWDG3 said:
Hello Van's members.

Recently a local RV9A owner was having problems with his tach and Trutrak autopilot falling off line simultaneously. I noticed he had what I now know to be a B&C 20 position bus. It's used as an essential bus supplying mostly avionics. A separate smaller B&C is labeled "main" supplying mostly lighting. In the past we installed a new radio stack and used panel mount breakers. So I installed another breaker for the a/p and put the tach on a fuse from the new avionics bus. Both work great now. Owner has no schematics of original installation.

Any members here experience issues with B&C bus blocks?

RV9%20bus_zpso98fplmd.jpg
Click to expand...

Been using the B&C Fuse Blocks for over 18-years and have over 3,000 flying hours. Never an issue with the Fuse Blocks. Only thing that B&C supplied that I had an issue with was the connector contact at the alternator. Took over 6-weeks to figure that one out.

Most issues have been bad grounds, bad connections, or bad crimps which would also be the same as a bad connection.
 
B&C 20 position bus

I used four of these in my IFR RV-7A and have not experienced any issues. I also use two 4 position units for items that require power all the time (always hot like EFIS clocks). My electrical system is a two battery system...


MWDG3 said:
Hello Van's members.

Recently a local RV9A owner was having problems with his tach and Trutrak autopilot falling off line simultaneously. I noticed he had what I now know to be a B&C 20 position bus. It's used as an essential bus supplying mostly avionics. A separate smaller B&C is labeled "main" supplying mostly lighting. In the past we installed a new radio stack and used panel mount breakers. So I installed another breaker for the a/p and put the tach on a fuse from the new avionics bus. Both work great now. Owner has no schematics of original installation.

Any members here experience issues with B&C bus blocks?

RV9%20bus_zpso98fplmd.jpg
Click to expand...
 
I have one question about the installation picture. The B&C connector looks as if it could be laying on the fuse block. There is a chance that the hot test connection on the top of one of the fuses could come into contact with the grounded B&C connector.
 
I don't believe the BNC is close to the #10 supply terminal. Good question though, I'll pass at to the owner.
 
Check the input stud

Make sure the nut on the input stud is tight. I have had one of those get loose in flight and cause intermittent power readings.

Andy
 
MWDG3 said:
I don't believe the BNC is close to the #10 supply terminal. Good question though, I'll pass at to the owner.
Click to expand...

The top side of the fuses have a place to put a volt meter across the fuse to check if it is blown. While recessed slightly it still puts a voltage potential very close to a ground (BNC connector)
 
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