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Cooktop - 2 wire to 220v 3 wire
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Posted by nschloss (My Page) on Sat, Jun 27, 09 at 22:06
| I'm trying to connect my GE Induction cooktop but find the instructions confusing. The cooktop has 2 wires - red & black plus a green ground. The house circuit has 3 wires black, red, white & bare ground. Anyone have experience on how to properly connect the 3 house wires to the 2 cooktop wires? |
Follow-Up Postings:
RE: Cooktop - 2 wire to 220v 3 wire
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| Red to red, black to black (although it really doesn't matter if you reverse them), and green to the bare ground. Cap the white with a wire nut and fold it back in the box, it's not needed in this situation. The cooktop is straight 240v while the house wiring can accommodate a 240/120 appliance. I'm assuming the circuit you're connecting to is appropriately sized for the cooktop. |
RE: Cooktop - 2 wire to 220v 3 wire
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| I've been wondering why they didn't do this a long, long time ago. We've got a lot of older grandfathered 3-wire installations, but code now wants 4-wire receptacles, with ground/neutral seperate. Alright, fine, but I always wondered: Why do we have 120/240 appliances anyway? Clothes dryers tend to have a 120V motor, but I can see no reason not to use a 240V motor instead. I can't see anything in a typical range that uses 120, with the possible exception of some of the electronic controls on modern ovens, which are low-voltage internally anyway, so if you're gonna use a 120-to-whatever transformer, why not a 240-to-whatever one? It would seem, to me, a lot simpler a solution! |
RE: Cooktop - 2 wire to 220v 3 wire
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| Cooktops I don't know about, but ranges and wall ovens typically have a 120V lightbulb inside (and some older ones had 120V convenience receptacles as well). |
RE: Cooktop - 2 wire to 220v 3 wire
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| "We've got a lot of older grandfathered 3-wire installations, but code now wants 4-wire receptacles, with ground/neutral seperate. " This only applies to 120/240v appliances. The OP has a straight 240v appliance. The neutral is not needed but a ground is. |
RE: Cooktop - 2 wire to 220v 3 wire
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| Mike - thanks for the confirmation. That's what I thought was meant but I feel better with some validation. Appreciate the response. |
RE: Cooktop - 2 wire to 220v 3 wire
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| "Cooktops I don't know about, but ranges and wall ovens typically have a 120V lightbulb inside (and some older ones had 120V convenience receptacles as well)." The manufacturers (probably at UL prodding) finally did away with the 'convenience receptacles' during the 1970s.
The stove did not have any secondary overload protection, meaning there was a 30-50 amp breaker feeding that receptacle. |
RE: Cooktop - 2 wire to 220v
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| The oven I want to buy is a 120/240v wall oven, and the spec says 20A circuit. If it's a 3wire connection, would a 10/3 wire cause damage when used in a 2-pole 20 breaker? My cooktop is a 120/240v surface mount, 40A and it has only two wires (black/red) and a bonding ground. Wouldn't that make it an 8/2 conductor for this circuit? About the oven then, if the oven has (I don't know yet) the same wiring (red/black/gnd), then could a 10/2 be used if it's a 20A circuit? I hope this response goes to my email. ;) |
RE: Cooktop - 2 wire to 220v 3 wire
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| ksvalentine, it would have been better to start a new thread for your questions instead of adding them to this existing and still active thread. The responses will not go to your e-mail. I don;t think this site offers this function. I hope you come back to check. Both your new appliances will need FOUR wires. Two hots, a white neutral and a green or bare ground. If the appliance only has a black and red it will be a 240v appliance, not a 120/240v appliance. |
RE: Cooktop - 2 wire to 220v 3 wire
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| peter racer- Thanx, this is my first time on this blog. I posted a new thread. |
RE: Cooktop - 2 wire to 220v 3 wire
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| "The oven I want to buy is a 120/240v wall oven, and the spec says 20A circuit. If it's a 3wire connection, would a 10/3 wire cause damage when used in a 2-pole 20 breaker? " No, 10 ga. is fine. A 20A is allowed to be as small as 12 ga. (provided that it doesn't have to be derated for some reason). You can always under-breaker a circuit, as long as whatever is feeding the circuit will run without tripping. |
RE: Cooktop - 2 wire to 220v 3 wire
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The manufacturers (probably at UL prodding) finally did away with the 'convenience receptacles' during the 1970s.
The stove did not have any secondary overload protection, meaning there was a 30-50 amp breaker feeding that receptacle. I've seen at least one with one of those pushbutton thermal breakers (like you find in the back of old TVs) for the receptacle. |
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