Portable device for testing electrical wiring circuits and power tools and equipment

Claim 1

A portable electrical testing device for testing electrical wiring circuits in power tools and equipment which operate from an outside electrical source supplied by a line, neutral, and ground conductor wire, said device comprising: a three-conductor wire power cord having a three-prong plug for connecting said device to a three-socket receptacle of said outside electrical source; a first test station having indicator means electrically connected to the conductors of said power cord for indicating the wiring polarity condition of said outside receptacle; a second testing station electrically connected to said first station having a three-socket receptacle for receiving a three-prong plug of a cable of the power tool and equipment being tested; said second station including a ground fault device having a test circuit connected to said receptacle which includes a fault indicator for indicating the existence of a defective circuit in said power tool and equipment; a third test station having a three-socket receptacle for receiving said plug of said power tool being tested, said third test station including circuit means connected to said third station receptacle for indicating the continuity of a ground circuit in said power tool; a fourth test station for testing the proper wiring of a three-wire extension power cable having a three-prong plug carried on one end and a three-socket receptacle carried on the other end thereof with line, neutral, and ground conductors connected therebetween; said fourth station including a testing circuit having a plug which includes a line wire prong, neutral wire prong, and a ground wire prong for receiving said power cable receptacle while said power cable plug is inserted into the receptacle of said second test station, said extension power cable being connected between said fourth and second stations during testing assuring proper line polarity and facilitating detecting of the reversal of conductors of said extension power cable, said test circuit including indicator means electrically connected to said prongs of said plug of said fourth station for indicating the wiring polarity condition of said power extension cable and said fourth test station including a second testing circuit for detecting reversal of the neutral and ground conductors in said power cable which includes an impedance load and switch means connected across said neutral and ground prongs, closure of said switch means producing a fault sufficient to cause said fault indicator to trip when said neutral and ground conductors are reversed.