The GFCI – Your Only True Lifeline

Welcome back, let’s Build Smart & Build Safe! On a construction site, a standard circuit breaker is designed to protect the building and the equipment—it is not designed to protect you. By the time a 20-amp breaker trips, there is more than enough current flowing to cause a fatal heart arrhythmia. For human protection, we rely entirely on the Ground Fault Circuit Interrupter (GFCI).

Some companies treat GFCIs as a nuisance because they "trip too often," but every trip is a warning that electricity is seeking a path to the ground—possibly through your body.

How the GFCI Protects You

A GFCI is a fast-acting circuit breaker designed to shut off electric power in the event of a ground fault in as little as 1/40th of a second.

• The Comparison: It works by comparing the amount of current going to the tool against the amount returning from the tool.

• The Threshold: If there is a difference as small as 5 milliamps, the GFCI senses that the current is leaking elsewhere (like through a person) and snaps the power off instantly.

• The "Nuisance" Trip: If a GFCI trips, it is usually because of a "leak" caused by moisture in a cord connection, frayed insulation, or a tool motor that is beginning to fail. Never bypass a GFCI to keep working.

Mandatory Testing & Inspection

OSHA requires that all 125-volt, single-phase, 15-, 20-, and 30-amp receptacle outlets that are not part of the permanent wiring have GFCI protection.

1. Daily Visual Check: Inspect the GFCI housing for cracks, burns, or moisture. If you are using a portable GFCI "pigtail," ensure the cord isn't pulled tight at the plug.

2. The Test Button: You must test the GFCI before each use. Press the "TEST" button to ensure the "RESET" button pops out, cutting power. If the power stays on when you hit test, the device has failed and must be taken out of service.

3. The "Daisy Chain" Limit: Do not plug a GFCI into another GFCI. This can cause "ghost trips" or, in some cases, prevent the devices from sensing the fault properly.

Implementation: The GFCI Morning Drill

Before pulling a trigger today:

1. Push the Button: Physically test every GFCI you are plugged into. If it doesn't "snap" when you hit test, it is defective.

2. Check the Connection: If you are working in a damp area, keep the GFCI and cord connections elevated off the ground using a stand or a "pigtail" protector.

3. Identify the Source: If the GFCI trips, don't just reset it. Inspect your cord and your tool for the "leak" before trying again.

4. Use GFCI Splitters: If plugging into permanent building power always use a GFCI splitter when you plug into the wall.

Please help us grow, share us with your friends and coworkers for a daily dose of construction safety tips!

-The Safety Man