Short version: I need to have a propane unit heater installed for a well-insulated 30'x50' x 14' ceiling garage in northern Minnesota. Should I run metallic cable to 20-amp outlet for a propane unit heater or just run the cable and leave slack for a future installation/installer?
I have a well insulated detached garage and the in-slab radiant boiler system is shot (boiler dead, plumbing bad, looking at >$4k to fix plus keep tabs on winter water lines to maintain it). I mothballed the slab lines with RV antifreeze for potential future use, but I'm planning for a forced-air propane unit heater instead as a replacement. (Won't get a ton of winter use and only needs to be kept about 45 degrees inside to keep water/equipment happy.)
I plan on having a suitable Sterling propane unit installed, and it's going to have to happen while I'm away. I want to get the electrical ready for potential installers. (Still trying to get bids submitted.) I'm told it just takes a 20-amp dedicated circuit, which I've already got thanks to the boiler circuit. I can easily re-route that power up into the corner where the forced air unit will go with some metal-shielded cable.
Do these units plug in with a 3-prong cord or should I leave the metallic cable with slack for the installers to patch it in directly?