"Nuisance Tripping" can trip you up! A ground fault circuit interrupter is a device that detects any leakage current in an electrical circuit and trips the circuit whenever the leakage is too great. Three types of GFCIs can be used at work sites: a GFCI receptacle, a portable GFCI or a GFCI circuit breaker.
When GFCIs are used in construction activities, they should be located as close as possible to the electrical equipment they protect. Excessive lengths of temporary wiring or long extension cords can cause ground fault leakage current to flow by captive and inductive coupling. The combined leakage current can exceed 5 ma, causing the GFCI to trip.
Other nuisance tripping may be caused by one or several of the following items:
- wet electrical extension cord to tool connections
- wet power tools
- outdoor GFCIs not protected from rain or water sprays
- bad electrical equipment with case-to-hot-conductor fault
- too many power tools on one GFCI branch, resistive heaters
- coiled extension cords (long lengths)
- poorly installed GFCI
- defective or damaged GFCI
- electromagnetic-induced current near high-voltage lines
- portable GFCI plugged into a GFCI-protected branch circuit
Remember, that GFCI does not prevent shock. It simply limits the duration so the heart is not affected. The shock lasts about 1/5 second and can be intense enough to knock a person off a ladder or otherwise cause an accidental injury.