A while back I was helping to install a piece of 1200A switch-gear. When it came time to join the main-breaker bus to the gear-frame bus, the respective sets of bars wouldn't line up perfectly. As a result, the screw holes for each set of bars were out of alignment by about 3/8" at maximum.
No amount of shimming and jockying the main was making a difference, so I ended up taking a C-clamp and using it to squeeze the two sections of bars together until all the screw holes lined up and the bolts could be inserted.
In retrospect, I have a bad feeling that this probably made the torquing of the bolts almost useless: When I took the C-clamp off, and the bars pulled away from each other, it seems like the shear force on each bolt would mean that it would require a lot more torque to get the same compression VS if the bolts dropped straight in the holes and there was no shear force.
Is there the potential for a high-resistance connection there, or am I worrying over nothing? If it is a problem, how should I solve it in the future?
-John
