Question on circuit for wall oven

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Old 03-25-19, 07:36 AM
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Question on circuit for wall oven

As part of a remodel we are installing a wall oven. The installation manual says the circuit required is 208v,60Hz 12 amp or 240v,60Hz 15 amp. Can I use a circuit already in place that used to go to a dryer. It is 240v,60Hz 30 amp using 10/3 with ground wire. 15 amp seems kinda low??
 
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Old 03-25-19, 07:54 AM
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You can re-purpose the existing dryer circuit if you replace the double-pole 30A breaker feeding this circuit with a double-pole 15A breaker. At the oven you will cap off and not use the white wire from the 10-3/g cable. Only the black, red and bare will need to connect to the oven.
 
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Old 03-25-19, 08:15 AM
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The installation manual shows for a 3 wire hookup that the green and white from the oven are both connected to the neutral wire from breaker? I assume by neutral it is the bare wire and not the white?
 
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Old 03-25-19, 08:51 AM
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Neutral is white. Green or bare is ground
 
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Old 03-25-19, 09:01 AM
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I was wrong. The dryer circuit has no bare wire. Only red, black, and white. So I assume I wire it like the manual shows: red to red, black to black, and white and green from oven to white from breaker?
 
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Old 03-25-19, 09:04 AM
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If the oven has a white wire, then you would connect it to the house circuit white. The ground and white would be kept separate because your house circuit has them separate. The instructions should have a four-wire installation procedure.

The confusing part is that ovens usually do not require a white wire, and the specs state 240V which does not require a white wire. Anyway, I think you have what you need to proceed.
 
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Old 03-25-19, 09:08 AM
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It looks like we posted at the same time--

If your existing circuit does not have a ground wire, there is no code-legal way to reuse it. Ungrounded circuits are considered obsolete and cannot be modified to a new purpose. The best installation per code would be to install a new three conductor plus ground cable from the panel to the oven. While this oven would only require 14-3/g, I would probably run at least 12-3/g or 10-3/g to enable future use with other ovens that require more power.
 
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Old 03-25-19, 09:09 AM
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The installation manual does have a 4 wire connection as well as 3 but my circuit only has 3 unless I run a new 10/3 with ground which I'm trying to avoid.
 
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Old 03-25-19, 11:47 AM
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Electrically a three-wire circuit works. They have a higher chance of electrical shock in some circumstances; which is why they were banned for ranges and dryers after 1996. Due to the grandfather rule, original three-wire circuits can be continued to be used as-is for their original purpose. However, changing the circuit for a new purpose invalidates the grandfather rule. What all this means is that it will work, but it will not be a code-compliant installation without a separate ground wire.

If your existing cable has an insulated neutral (not bare or braided), it would be legal to run just a green #10 ground wire from the ground bar in the panel to the oven. This saves the money of replacing the existing cable, but is still about 90% of the work.
 
 

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