Installing a cooktop & single oven


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Old 09-21-08, 01:32 PM
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Installing a cooktop & single oven

I'm replacing a freestanding electric range and in its place will be a cooktop with a single wall oven below. There is a 240v junction box that powered the range. I need two to power the units. Can I replace the single receptacle with a dual OR will I need to run a wire from the fuse box? Are there any other options?
 
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Old 09-21-08, 07:07 PM
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It would really help if you could tell the current circuit size and number and colors of wires for the existing as well as the circuit requirements of the new equipment.

Does the new equipment need to move from the current location or will it install in the same place?
 
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Old 09-22-08, 05:01 AM
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The new equipment will be placed in the same location as the old equipment. I believe the current circuit size is 240V and see only 3 wires (white, red, black). The new equipment is 240V.
 
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Old 09-22-08, 05:30 AM
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OK, you confirmed that both the new and old are 240, but now we need the circuit size. This may be listed as something like 30 amps, 50 amps. You can check the breaker handle for the current circuit size, and the paperwork for the new circuit size.
 
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Old 09-22-08, 09:50 AM
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40 amps is powering the stove. The cooktop requires 40 amps and the oven 30 amps. Can the old junction box be removed from the floor and run the wire into a new junction box mounted to the wall and connect the oven & cooktop to the power all together?
 

Last edited by greekzilla; 09-22-08 at 11:05 AM.
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Old 09-22-08, 02:37 PM
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It is allowable to tap a circuit for ranges/cooktops, providing two receptacles for two devices. The trouble is that Code says your conductors have to have an ampacity not less than the maximum load... which in your case is 70 amps. This would mean 6ga THHN/THWN. You must also use a 50A breaker on 6ga, which raises the possibility of nuisance tripping when doing a lot of cooking. You can't use a 70A breaker on 6ga because the insulation on the breaker is only rated for 60C, while THHN is rated for 90C.
If you have 8ga wires in your walls the wire is too small to support both the oven and the range. If you do have 8ga, then you have to run new wire. If that's the case, I suggest running two new cables, one each for the stove and the countertop unit. One goes bad, you still have the other, and if someone ever installs a really high-draw stove, it won't overload your 50A breaker.
The flip side is that stoves almost never pull the current listed on their back plate... you'd have to have every burner on High and the oven running a self-cleaning cycle at the same time. It could happen though, so the wire needs to be able to handle it. This is why many stove installations continue to function on underrated circuits, it's like saying the tires on your car are okay because you never drive over 30mph.
 
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Old 09-22-08, 04:45 PM
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I looked at the current setup and there is no identification on what type of wiring (its a thick cable 4 / 6ga) is being used for the current setup. I noticed that my fuse panel doesn't have any available spots for an additional circuit breaker. I want to do this the correct way since everything is out of the way.
 
 

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