Ground Fault Circuit Interrupters (GFCI)
GFCI General Information
- Protects you against electric shock
- It’s a fast acting circuit breaker
- Continuously monitors amount of current going to a tool and compares it to the amount of current returning along the electrical path. If the difference is more than 5 milliamps the GFCI will trip
- When a GFCI trips it shuts off the electricity in 1/40 of a second
- The GFCI will not protect you from line-to-line contact hazards (i.e., holding two “hot” wires or a hot and a neutral wire in each hand)
Jobsite Rules:
- ALWAYS use a GFCI when using plug and cord equipment, especially extension cords
- ALWAYS test the GFCI before use by plugging it in, pushing the test button and then pushing the reset button
- If the GFCI won’t test or reset then remove it from service immediately
- You should document all your inspections, even on portable GFCI (“pig tails”)
- ALWAYS plug the GFCI in at the source of the electricity (outlet or receptacle)
- Surge Protectors are NOT GFCI’s and must not be used on construction sites
- If a GFCI interrupts the circuit and stops the current flow to the appliance, you should unplug the appliance, and then press the “reset” button. If you try to plug the appliance back in and the GFCI pops again, then you should get the appliance serviced and repaired before trying to use it again, or replace it with a properly working unit
- If you find a GFCI that does not work properly or you see that it has some physical damage, you need to notify your supervisor so that it can be promptly repaired and returned to service.
Tool Box Talk based on NMGC submitted by Tyler Quinn – P66 Bayway