ray, not sure witch wire you are talking about
the 3 wires on the bottom red,white,black are from the main and feed this box.
now, why the hell cant i use that buss bar as my ground
the white wire goes directly to the service ground in the main.
i am so used to doing auto electrical that none of this makes sence to me
Ralph,
I am just throwing this at you because it is the right way to do it.
Grounding is very important for several reasons, the most obvious is to eliminate any shock hazards, my uncle was bit by a three phase welder plug at a body shop 15 years ago and spent 6 days in the hospital on a heart monitor ans was treated for some burns on the hand.........
The sub panel in your garage does not seem right, maybe OK several years ago, but not to today's standards. I would pull a separate ground to outside and run a ground spike, if you already have a ground spike close to the garage (normally bonding the water pipes in the house) then you could bond to that.
Do not bond to the neutral, it used to be done, but is not right, there should have been a separate ground pulled for the sub panel....
Also, just a pet peeve, if the breaker is bigger than the maximum fuse size of the compressor, use a service disconnect with the appropriate size dual element fuses (may say HACR on them).....Call if I can help.
GT