Hi, I'm replacing an old pushmatic panel in my garage with a new siemmens main lug and the main cables will not be long enough it reach with the new panel mounted upright. The old panel has ridged conduit going into it with the conduit running right along a beam so I can't mount the panel lower to gain the extra cable but I will have enough if I mount it upside down. Will this be ok?

also make sure that you have fall in your wires so that the electrons will flow good,LOL