Pason wrote:
The garage has a gas line for a heater to it so not running a ground
wire and bonding the neutral and ground in the subpanel wouldn't work,
right?

Right. You have to run a ground. But maybe the conduit is ground
enough already? Does it go all the way to the main panel? How are the
joints made up?

What is the reasoning for requiring a 2nd ground rod for a seperate
building? I can see if it's on the other side of a farmyard, but this
garage is literally less than 10 ft away. With a bigger house it could
easily be attached.

The second ground rod would be just to make **really** sure you have a
good ground. You would do that if it was supplying the only ground for
the garage.

What about running three #8 wires and a #10 ground for a 40 amp
subpanel? Hard pull? Anyone know a good resource for EMT IDs or areas
and wire gauge areas?

Three #8's is a full conduit. Maybe two #8 hot wires and two stranded
#10's? (You may not need a full-sized neutral) I don't know; I don't
have the equations handy to calculate if that would exceed the maximum
fill.

It's going to be a hard pull if there are any bends.
This would be a *lot* easier if you had a 3/4" conduit instead of 1/2"

I'll let other folks that know the /up-to-date/ code say if there's a
way to do this safely with three #8 wires, or two 8's and two 10's.

Best regards,
Bob