Please suffer a fairly green question.

I'm planning a house and I'd like to have a welder outlet in both the
basement and the garage. I'm clear about the wire size, type, breaker
etc to use. My question has to do with routing the wire.

95% of the house is concrete, and wiring is in conduit (IMT).

My breaker box is in the basement. Conduit coming out the side of the
breaker box carries conductors that serve the basement. Conduit
comming out of the top of the breaker box carries conductors serving
the garage. If want both welder outlets on one circuit, how do I
route the wires? (PS. I have only one welder, one plugged in at a
time.)

I could run the circuit from the breaker in the breaker box thru the
side conduit to the basement welder outlet, then and back track,
re-entering the breaker box and out the top conduit to the garage
welder outlet. But is this legal?

Can someone give me the NEC reference?

--wahzoo