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Ground Wire Guage

Name: Betty  City: Putnam County, NY

Question: I wired my new cooktop using #12, 2 wire Romex with groud wire. The installation instructions say that it requires a #10 ground wire. The unit is 3800 watts (no amps given). I calculate the amps as 17.25 (3800/220). Rather than buying a roll of #10, 2 wire Romex, can I just add a bare or coated #10 wire back to the main panel , or does it need to be in some sort of sheathing? Thank you for your help, Betty

Name: joe | Date: August 26, 2005, 19:40
Answer: 3800watts at 220volts will draw at least 17.25 amps. Your calculations are correct...The problem is that if you use a 20amp circuit, electrical codes only allow for 80% of the maximum amperage capacity to be used for safe operation....This means if you use #12-2 wire and a 20 amp circuit, you can only safely use 16amps on that circuit (20amps x 80%)....This means if you place this 3800watt appliance on a 20 amp circuit using 12-2 wire, you will overload the circuit (17.27amps).....The answer to your dilemma is to go up to the next size gauge wire and circuit breaker....Your cooktop needs to be wired with #10-2 wire with ground and a 30amp breaker for safe operation....You will have to rewire with #10-2 with ground from the service panel and install a 30amp breaker to safely operate this appliance.

Name: doc | Date: October 17, 2005, 11:13
Answer: I agree with Joe and will add this if that electric range has anything like a clock or timer that is 120 volt then you will need 10/3 with ground You can no longer use the ground fore the neutral /grounded conductor