You are unlikely to get much air flow thru 75+ feet of tubing that will fit
in that conduit. For intermittent use you could add a tank in the garage. I
would suggest a small compressor in the garage and if you need more
electrical capacity use the existing conduit. The existing two conductors
plus a ground would power a 240V compressor.
Don Young

"andy" wrote in message
oups.com...
Hi folks.
I am hoping to run an air line from a compressor in my basement to my
detached garage through a burried steel electrical conduit. The length
of the conduit is approximately 75'. The conduit currently contains
two unused 12 gauge conductors and looks to be about 3/4" in diameter
and heavier than your standard EMT . Does anyone see any potential
problems with this arrangement?

I was thinking flexible hose, any suggestions as to type?

Thanks,
Andy
Lynn, MA

(Ideally I would have the compressor in the garage, but I don't have
enough circuits/capacity out there. - I basically use the air for
blowing around sawdust)