IDEAL INDUSTRIES INC. Circuit Tester for use on 120VAC circuits, warns against faulty wiring in 3-wire receptacles. Tests for correct wiring, open ground, reverse polarity, open hot, open neutral and hot/ground reversed. For wiring configuration testing, verify proper wiring configuration by noting the bulbs lit on the tester. Simply compare the bulbs lit to the legend on the product label to determine the wire condition. If a miswired condition is found, stop any further testing and consult a qualified electrician to rectify the problem. For GFCI testing, operate the test button on the GFCI installed in the circuit. The test light will turn on, indicating the activation of the GFCI test. The GFCI must trip. If the GFCI does not trip, consult a qualified electrician. If it does trip, reset the GFCI. Then, insert the GFCI tester into the receptacle to be tested. Activate the test button on the GFCI tester for a minimum of 6 seconds when testing the GFCI condition. Visible indication on the GFCI tester must cease when tripped.