80-Amp Feeder and Lighting for a New Pole Barn in Battle Ground, WA

A pole building goes up fast and then sits dark until somebody runs power to it. This one in Battle Ground got a real 80-amp feeder instead of a cord from the house. We did the run, the disconnect, the grounding and the lights.

Sizing the feeder

The feeder is on an 80-amp Homeline breaker at the house and protected again by 80-amp fuses in a 100-amp fused disconnect at the barn.

That can look like overkill, so here’s why:

• The breaker at the house protects the feeder over its 70-foot run
• The fused disconnect at the barn is a shutoff at the building, which code requires on a detached building with its own breakers
• A 100-amp disconnect with 80-amp fuses is normal. You size the box to the frame and the fuses to the load.

Seventy feet of #2 URD handles that easily. Wire size on a feeder depends on the load, the distance and how much voltage drop you’ll accept. Get it wrong and the lights dim every time something starts up.

Two ground rods

The building got two ground rods.

One rod is only allowed if you measure it and prove it’s good enough. Almost nobody does that, so the rule in practice is two rods, spaced apart and tied together. On a rural Battle Ground lot with dry summer soil, two rods is the right call anyway.

The building is bonded, and the ground wire runs with the feeder. You need both. A detached building that relies only on ground rods to trip a breaker in a fault is one of the more dangerous shortcuts out there.

Lighting a truss ceiling

Inside, we ran LED lights between the open trusses, with a high bay where the ceiling was tallest.

Pole barns are hard to light because the trusses are both in the way and the only thing to mount on. Running strip LEDs along the trusses gives even light down the whole building, and you can reach them from a ladder instead of a lift.

Outside, we put a coach light at the walk-in door. It’s small, and it gets used every time somebody heads out there after dark.

Doing it while the barn is empty

All of this was easier because the barn was new and empty. The trench didn’t cross any landscaping, the walls were bare, and the ceiling was clear.

The same feeder and outbuilding work two years from now, with a shop full of equipment and a finished yard, costs a lot more. Our guide to powering a detached shop or barn covers what to decide before the slab goes in.

Putting up a pole building around Battle Ground, Yacolt or Amboy? Call 360-828-7143 or size the feeder with us before the trench closes.