Questions about grounding requirements and the effectiveness of GFCIs used in connection with Portable Generators have caused debate in the industry. Ground fault is potentially deadly. Electrocution can occur when a worker uses a faulty tool and current returns to ground or a worker contacts the hot or positive side of a circuit and provides a path to ground. CSAO conducted a series of tests to determine the effectiveness of GFCIs used on Portable Generators in typical construction scenarios. The generators were the most common type found in construction - portable units that can be handled and moved by one or two workers.
Grounding can vary from one place to another, even when both are relatively close.
In one test the GFCI tripped when the generator was grounded in wet earth but failed to trip when the generator was grounded 1OO feet away in soil that was drier and better drained. A GFCI plugged directly into the generator failed to detect any ground fault and didn't trip even when the current leak reached higher than acceptable levels. The GFCI did trip, however, when it was placed at the tool. The GFCI should be located closest to the generator . Under certain conditions, some generators that are not grounded can become grounded, exposing personnel to the risk of electrocution if GFCI protection is not provided.