Temporary Power — GFCI on Construction Sites

Every 125-volt receptacle used for temporary power needs GFCI protection, whether it is built into the outlet or provided by an inline device. The alternative for certain higher-current tools is an assured equipment grounding program, but GFCI is the standard.

Temporary is where corners get cut, and that is exactly why the rule is strict. The guy standing in a mud puddle with a worn drill cord is the person this section keeps alive.

When it applies

Temporary power on a job site needs GFCI protection on the receptacles workers plug into. You have people standing on wet ground running tools with beat-up cords. That is exactly the shock scenario a GFCI is built to catch.

Common mistakes

• Assuming temporary means the safety rules relax. They do not. Temporary wiring carries some of the tightest GFCI requirements on the book.
• Feeding tools through a spider box with no GFCI and hoping the cords hold up.
• Using the assured equipment grounding program as an excuse to skip GFCIs without actually running the program.

In the field

I run every construction temp service through GFCI-protected receptacles, no exceptions. I have watched a worker grab a drill with a cracked case in the rain and the GFCI popped before he ever felt it. On a job site the ground is wet, the cords get run over, and the tools take a beating. That protection is the cheapest life insurance you will ever install.