I am replacing old oven with double oven, current oven is on a 20 amp breaker, old wiring can not make out the gauge.

The new double oven is convection 27" ovens, the following is the Power Specs:

Amp Rating at 240V 30
Bake Wattage 2640
Broiler Wattage 3400
Convection Wattage 2500
KW Rating at 208V 5.1
KW Rating at 240V 6.8

What I need to know is could I use the existing wiring and change breaker or do I need to run a different gauge wire and if so which.

I am replacing old oven with double oven, current oven is on a 20 amp breaker, old wiring can not make out the gauge.

The new double oven is convection 27" ovens, the following is the Power Specs:

Amp Rating at 240V 30
Bake Wattage 2640
Broiler Wattage 3400
Convection Wattage 2500
KW Rating at 208V 5.1
KW Rating at 240V 6.8

What I need to know is could I use the existing wiring and change breaker or do I need to run a different gauge wire and if so which.


Wiring and breaker must be 40amps minimum.(NEC210.19) That means a #8-3 w/gnd hooked up to a 40 amp breaker. There is an exception if demand factor is for two cooking appliances but I don't have the 2005 book right now. This is based on a 240v single phase residential hookup. Nm:)

There is a chance your house was wired up with the standard #8. Solid #8 is 0.1285'' in diameter, or just over 1/8''. #10 is 0.1019'', and #12 usually used with a 20 amp breaker is 0.08081''. You should have something able to measure close enough to tell the difference, maybe even a drill gauge.

Labman,

Most residential wiring is done in romex. The UL and Nec require the outer sheathing be marked every 12 inches with the type (insulation ), conductor bundling, awg, mfr data... etc. I am not sure why it would be necessary to try and measure the conductor size. This can be misleading because #8 copper comes in stranded and Aluminum also. The cable size suggested was for copper. Nm:)

''old wiring can not make out the gauge.'' ''Solid #8 is 0.1285'' '' I guess something old enough not to be able to read the gauge could be aluminum, but very little was ever used in residential construction. It is also possible he can't see much of the wire.

''old wiring can not make out the gauge.'' ''Solid #8 is 0.1285'' '' I guess something old enough not to be able to read the gauge could be aluminum, but very little was ever used in residential construction. It is also possible he can't see much of the wire.

Labman, There is no point in even mentioning the size of conductor in the reply you made. The 12-2 cable that exists is incorrect for the new installation. Do you agree on that? Nm

What there is no point in, is your continuing attempts to prove I am wrong. In my first post, I only allowed there was a chance that the wire was the #8 needed. I agree that with a 20 amp breaker that likely it is #12. You have no proof that it is #12. If it is, my simple check will verify it. I gave the guy a quick, easy way to check wire he said the markings wire unreadable. OK, I left out the remote possibility it was aluminum. So what's your problem? Oh, you can lose the lecturing tone of your posts.

This has gone long enough. I will not be responding to any more such posts.

What there is no point in, is your continuing attempts to prove I am wrong. In my first post, I only allowed there was a chance that the wire was the #8 needed. I agree that with a 20 amp breaker that likely it is #12. You have no proof that it is #12. If it is, my simple check will verify it. I gave the guy a quick, easy way to check wire he said the markings wire unreadable. OK, I left out the remote possibility it was aluminum. So what's your problem? Oh, you can lose the lecturing tone of your posts.

This has gone long enough. I will not be responding to any more such posts.

Well Labman,

Maybe I am wrong and you are correct. I am surprised that we are confusing the people asking questions by giving two different answers. I guess I am going to stay out of this forum in this case. Sorry to have left an ill feeling with you. This is not what I was even thinking about. Nm