Mike Dolt Enterprises
Mike Dolt Enterprises
User: EDawes, Location: MA
Asked on: Tuesday, April 5, 2011 at 10:11 am EDT
Answered on: Tuesday, May 14, 2024 at 3:46 am EDT
Question: A 46,000 sq foot building site has the steel skeleton up with the 2nd floor deck serving as a porous roof. They are using corded drills to screw pre formed panels for the walls. 6 to 8 drills are plugged in at one time. 4 duplex (GFCI) outlets are wired in a wall by the entrance. A 20 amp breaker is on the outlets. They are running a 50 ft cord with a spider box. They are running 5 100 ft cord in series to reach men on the far wall. The spider is also GFCIed. A proven gfci tester will not pop either GFCI in the cuircuit. All cords are 12 hard service. Aside from wiring the building is there a good solution to this long run? The GFCI TESTER still works on regular GFCI outlets but will not pop this one with 2 GFCIs in series?
Troubleshooting the GFCI Circuit Confirm that the GFCI outlets are installed correctly and wired to the correct terminals. Check the wiring diagram for the outlets. Verify that the GFCI testers are functioning properly by testing them on known working GFCI outlets. Measure the line and neutral voltage at the GFCI outlets using a multimeter. They should be approximately 120V. Use a clamp-on meter to measure the current draw on the GFCI circuit. If the load exceeds the rated capacity of the breaker (20A), the GFCI may be tripping.
Solutions for the Long Run Upgrade the circuit breaker
Install a higher-rated circuit breaker (e.g., 30A) that can handle the increased current draw from the multiple drills.
Add additional outlets
Install more GFCI outlets along the length of the wall to reduce the distance that the cords need to be run.
Use a subpanel
Install a subpanel near the work area and run a dedicated feeder from the main electrical panel. This will provide additional capacity and reduce voltage drop.
Consider using a transformer
Use an isolating transformer between the GFCI outlet and the drills to reduce the risk of ground faults and voltage drop over long cord runs.
Limit the number of drills
Reduce the number of drills plugged into the circuit at one time to prevent overloading.
Regarding the Spider Box The GFCI protection should be located at the outlet, not in a spider box. A GFCI in a spider box may not provide adequate protection due to the potential for voltage drop and ground faults.* Replace the spider box with a standard extension cord that is rated for the load. Flag for review