Pason wrote:
It is a detached, but why do you say that only for an attached?

An outbuilding technically can only be fed from one circuit. If both
circuits run thru the same conduit and disconnect at the same box in the
garage, it's probably not a big deal.


I think that would still be possible, but again it would only be 30
amps, right? If that's the only option that's okay however I would like
to maximize the power to the garage.

Two options. I'm not sure which is better under the 2006 electric code;
my code book is a few years old:

To maximize the power to the garage AND reuse the existing conduit, pull
the existing wires out and replace with three #8 THWN wires. That will
give you a 40A 240V service with 2 hot wires and a neutral. You will
have to make a new ground at the garage and bond it to the neutral, and
you can't have any other grounded pipes or wires connecting the garage
to the house. (CATV, telephone, metal gas or water pipes, etc.) The
subpanel in the garage needs to be rated for Service Equipment, but
that's not a big deal because almost all of them are.

You might can run the three wires and use the EMT as a separate ground,
but I don't know if that's kosher. You'll still need to drive a ground
rod (or two) at the garage. In that case, you would not bond the ground
and neutral at the garage subpanel, and you wouldn't care about
phone/gas/water lines connected back to the house.

Best regards,
Bob