RBM wrote:
The first thing to do is find the junction box in the garage, where the
conduit comes into when it comes out of the ground, separate the feed wires
from the load wires and test them for proper voltage.

.... and test again, with a modest load applied (100-watt trouble light
or something similar).

I think the first guy who responded (Jeff) has it right.


If you don't have it,
check it at the other end of the conduit before it goes underground. This
will at least give you some idea of where the problem is