pecanflyboy
Well Known Member
My instrument panel was professionally built and installed by the original builder. It uses several rows of Klixon 7277 circuit breakers (CB's). These CB's are .75" tall. The rows are separated by 1" which gives at least 1/4" between each breaker. Seems like plenty, until.....
During some behind the panel maintenance, I discovered that the brass bus bar screw heads, and the screw heads from the output side of the row above, were making contact with each other:
https://drive.google.com/file/d/1G4xpH8ayd2W3nq3_sd1mS9UwCnhlNx-J/view?usp=sharing
As you can see, the screw heads on the output side of the CB row above, were touching the bus bar screw heads below, essentially by-passing the CB. My temporary fix was to install flatter headed screws which are shown in these pictures, and plastic insulators between the CB's.
https://drive.google.com/file/d/1o46Oxx4K3zESus_itqT-fVvpeFJKft7x/view?usp=sharing
The permanent fix was going to either involve a re-fab of the CB panel, or creating separation between the screw heads. I decided to start by removing the bus bars, and installing flat head screws.
Bus bar with pan head:
https://drive.google.com/file/d/1PNF4vI3WxUi1c6TLhCmjfaRrL61q9laC/view?usp=sharing
I countersinking the bus bars:
https://drive.google.com/file/d/1HKRFDgnK818XRURqIfsnVZetru-fvvgG/view?usp=sharing
And installing flat head screws:
https://drive.google.com/file/d/1rjP1AlTc-w2z6pahufwAwUTHstvndhpk/view?usp=sharing
The result is much better clearance:
https://drive.google.com/file/d/1LG9jgFQQ7V95GsZVDiY73m0ckN5dzueV/view?usp=sharing
https://drive.google.com/file/d/1omEHHaoOS9AfQyv6YBLu0UqeaJ9ySNdx/view?usp=sharing
I may even try to install the flat heads on the output side to increase the clearance. I think you would need at least 1 1/4" between the CB's to make clearance between the hardware. You could also group the bus bars together.
Check those CB's!
During some behind the panel maintenance, I discovered that the brass bus bar screw heads, and the screw heads from the output side of the row above, were making contact with each other:
https://drive.google.com/file/d/1G4xpH8ayd2W3nq3_sd1mS9UwCnhlNx-J/view?usp=sharing
As you can see, the screw heads on the output side of the CB row above, were touching the bus bar screw heads below, essentially by-passing the CB. My temporary fix was to install flatter headed screws which are shown in these pictures, and plastic insulators between the CB's.
https://drive.google.com/file/d/1o46Oxx4K3zESus_itqT-fVvpeFJKft7x/view?usp=sharing
The permanent fix was going to either involve a re-fab of the CB panel, or creating separation between the screw heads. I decided to start by removing the bus bars, and installing flat head screws.
Bus bar with pan head:
https://drive.google.com/file/d/1PNF4vI3WxUi1c6TLhCmjfaRrL61q9laC/view?usp=sharing
I countersinking the bus bars:
https://drive.google.com/file/d/1HKRFDgnK818XRURqIfsnVZetru-fvvgG/view?usp=sharing
And installing flat head screws:
https://drive.google.com/file/d/1rjP1AlTc-w2z6pahufwAwUTHstvndhpk/view?usp=sharing
The result is much better clearance:
https://drive.google.com/file/d/1LG9jgFQQ7V95GsZVDiY73m0ckN5dzueV/view?usp=sharing
https://drive.google.com/file/d/1omEHHaoOS9AfQyv6YBLu0UqeaJ9ySNdx/view?usp=sharing
I may even try to install the flat heads on the output side to increase the clearance. I think you would need at least 1 1/4" between the CB's to make clearance between the hardware. You could also group the bus bars together.
Check those CB's!