In the barn I had years ago, we ran electric high along the back wall (the outer wall of the barn) so we could hang fans. I don't like fans blocking the stall fronts and wanted to have them angled down from over the back corners of the stalls so that worked well.
We did put in some wall outlets in the grooming stalls and on the aisle by the tack room to plug in things like clippers, the vac, etc...
********** We move pretty fast for some rabid garden snails.
Make sure your contractor is familiar with the electrical codes for high moisture/corrosive conditions around farms and dairies. There's quite a difference between them and commercial, residential, and industrial facilities!
Horse pee and poop will do a number on galvanized fittings in a hurry!
In general, the outlets must be higher above the ground and in corrosion-proof conduit and fittings. Everything must be ground-fault protected. A separage ground wire should be run rather than relying on the conduit for the grounding (which wouldn't work with corrosion-proof conduit anyway).
Our receptacles are 7' above the floor with six stalls per circuit breaker so heated buckets won't overload the circuits. The receptacles are also on separate circuits from the lighting. We used vapor-tight fixtures with wire guards above the stalls, and put 100 Watt-equivalent CFL bulbs in the fixtures.
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