#6 Alum Cable and Ranges

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rrrusty

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I have running across an issue on quite a few of the remodels and that the cable that is ran to the range is # 6 seu and put on a 50 amp breaker;I checked in the article regarding the allowable ampacity of seu/ser/nm cable and we are supposed to use the 60 deg column so #6 al would be rated at 40 amps; did the ampacity rule change or what? how was/ is this allowed?
 
Re: #6 Alum Cable and Ranges

In the 2002, 338.10(B)(4)(a) specifically excludes 334.80. 334.80 seems to be what forces us to use the 60? rating on NM.

So could it be that you could use the 75? rating for SER used as a branch circuit? That would seem to allow 50 amps, maybe.
 
Re: #6 Alum Cable and Ranges

Rusty, do you need a 50 Amp. range circuit? Many name plate ratings are less than 40. Could be easier to change the breaker.
 
Re: #6 Alum Cable and Ranges

Don't forget the receptacle needs to be 75deg also. That is if you're using a recep. I checked some years ago and the recep's were only 60 deg.
 
Re: #6 Alum Cable and Ranges

Originally posted by georgestolz:
In the 2002, 338.10(B)(4)(a) specifically excludes 334.80. 334.80 seems to be what forces us to use the 60? rating on NM.

So could it be that you could use the 75? rating for SER used as a branch circuit? That would seem to allow 50 amps, maybe.
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I agree with George. Although the requirements for installing NM cable, as outlined in parts 1 & 2 of Article 334, apply to SE cable the provisions of 334.80 do not. 334.80 limits the ampacity of type NM cable to 60 degrees in table 310.16. This would not apply to SE cable if the conductors were rated for 75 degrees and the breaker and receptacle also had a 75 degree rating. Therefore at 75 degrees your #6 AL cable would be good for 50 amps.

George I like the new signature. ;)
 
Re: #6 Alum Cable and Ranges

New double oven requires a 50 amp circuit and have been debating to use old 3 wire or pull in a new circuit using #4ser
 
Re: #6 Alum Cable and Ranges

Originally posted by infinity:
Therefore at 75 degrees your #6 AL cable would be good for 50 amps.
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True, but we must also take into account what Larry said. The terminals on a range receptacle are probably only 60 C. So this installation is limited to a 60C ampacity.
 
Re: #6 Alum Cable and Ranges

I'm surprised no one has picked up on this yet:

Originally posted by rrrusty:
# 6 seu
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This installation is not code compliant at all. The grounded conductor feeding ranges and dryers must be insulated. The cable must be SER or 3 wire W/G NM cable.
 
Re: #6 Alum Cable and Ranges

You guys got me curious so I pulled a P&S range receptacle out. The terminals are rated for 75 degrees c.
 
Re: #6 Alum Cable and Ranges

My computer or IP is not working properly. "sorry" the breaker termination is it rated at 60c to 75c? use lower.110.14 and 250.140 exeption (3)
 
Re: #6 Alum Cable and Ranges

OK guys, I'll show my ignorance again ... how does 8/3W/G NMB figure into this ... a previous employer used with a 50 amp breaker ... smaller wire, easier to hook up ... did I goof ??
 
Re: #6 Alum Cable and Ranges

mario, check termination provisions 60c 110.14 also (B signifies 90c) Just use that for derating ampacity due to ambient temps 310.16
 
Re: #6 Alum Cable and Ranges

Here I Go Again !! Don't have a "Hard Copy" Code Book here but do have "Computer Version" 2002 .. can't seem to find ampacities specifically for type NMB (ain't quite the greatest Program).. A Nudge in the right direction would be great .. Thanks .. M :confused:
 
Re: #6 Alum Cable and Ranges

Mario, you want find NMB but try 334.80 for NM, NMC, and NMS, then read the FPN to 334.112

Roger

[ January 17, 2006, 04:31 PM: Message edited by: roger ]
 
Re: #6 Alum Cable and Ranges

Mario:

IF you call that #8 a "tap conductor" (tapped from the breaker to the range outlet) you are allowed to use up to a 50 Amp breaker on it

See NEC 210.19(A)(3) Exception No. 1
 
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