40 Amp or 50 Amp for Induction Cooktop


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Old 10-13-10, 06:52 AM
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40 Amp or 50 Amp for Induction Cooktop

Howdy everyone, long time reader... first post.

My in-laws are in need of a new cooktop for their kitchen and are looking at induction cooktops. Some of the models they are looking at say they should have 50amp breakers. The previous cooktop was connected by only a 40amp break. Is it as simple as just swapping out the break? Is 40amp enough? Any thoughts on this would be appreciated.

Thanks
Andy
 
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Old 10-13-10, 07:12 AM
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You will have to check the gauge of the wiring to determine if you can swap the 40amp circuit to a 50. The gauge of the wire should be stamped on the sheath of the cable and will say something like 10/3, 8/3, etc.
 
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Old 10-13-10, 07:13 AM
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thanks for the quick reply... which gauge goes with which breaker?
 
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Old 10-13-10, 07:22 AM
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Number 8 is good for 40 amps, #6 for 50 amps. All sizes based on copper, aluminum would require larger sizes.
 
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Old 10-13-10, 08:45 AM
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You should also pay attention to the number of conductors. Most old range/cooktop circuits have only three wires. The new standard is to have four wires. Some new units can work with either three or four wire circuits, but some require the modern four wire circuit.
 
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Old 10-13-10, 08:49 AM
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i just took out the old cooktop, it had 3 wires + the ground (so 4). I need to double check on the gauge though before swapping out the breaker.

Thanks for all the help everyone!
 
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Old 10-13-10, 10:53 AM
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nevermind, I just re-read the OP.. im slow today!
 
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Old 10-13-10, 06:22 PM
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Ok, so i checked out the wire tonight at my in-laws. It is a little different and I am having a hard time determining the gauge.

Here is what is says

Stabiloy AA-8000 al type se cable style r XHHW 600v 4 crds 6 al 1993

Will this handle a 50 amp breaker
 
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Old 10-13-10, 06:32 PM
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It is #6 ga XHHW (service entrance) type aluminum cable, with 3 conductors plus ground. This is rated up to 60A. It'll work. Now find the electrician who wired your house and give him a hug for thinking of future upgrades!
 
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Old 10-13-10, 07:02 PM
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Sorry to disagree with you JM, but #6 AL SE rated in the 60 degree column is only good for 40 amps. The 90 degree column cannot be used for SE cables. This changed in either the 05 or 08 NEC.
 
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Old 10-13-10, 07:54 PM
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Originally Posted by JerseyMatt View Post
It is #6 ga XHHW (service entrance) type aluminum cable, with 3 conductors plus ground. This is rated up to 60A. It'll work. Now find the electrician who wired your house and give him a hug for thinking of future upgrades!
Sorry to stop ya in track the codes did change on the alum SER cable and you are only restricted to 40 amp breaker on this size and that basied on 60C rating not the 75C or 90C at all

Merci.
Marc

P.S PCboss it was changed in 05 NEC
 
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Old 10-13-10, 09:32 PM
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Huh.. Interesting. I didn't catch that. So basically there's no advantage to wiring large branches with Al SE over Romex anymore.. That sucks..

I checked real quick, but it looks like this was actually a 2008 revision. So TECHNICALLY, if the OP's locale is still using NEC2005 or earlier, it could still be done legally using the 90C column.

It seems odd to me (and from my reading, a lot of EC's apparantly) that it's acceptable to use the 90C column for Al feeders, but not for branch circuits. Both have the same probability to run through insulation.
 
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Old 10-14-10, 07:32 AM
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Unless the terminations are also rated 90 degrees you still need to use a lower column. The 90 degree column can be used as the starting point for derating.
 
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Old 10-14-10, 08:07 AM
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If you are on 2005 or earlier code in your area the cable is allowed up to 50A with 75C terminations. If you are on the 2008 code, it has been reduced to 40A in all circumstances.
 
 

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