SE-R cable
- Thread starter sparky76
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Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
What code cycle do you reference?
- Location
- Logan, Utah
Are you using the 2008 NEC as the answer depends on what code cycle you are working under.
Under the 2005 NEC using Table 310.16 and the 75 degree column #2 Aluminum SER cable has an ampacity of 90 amps.
Under the 2008 NEC due to a change in 338.10(B)(4)(a) you are limited to the 60 degree column of Table 310.16 so the ampacity of #2 Aluminum SER cable is 75 amps.
I am assuming by the use of the term "subfeeding" the that feeder in question is not a main power feeder and Table 310.15(B)(6) would not apply.
Chris
Under the 2005 NEC using Table 310.16 and the 75 degree column #2 Aluminum SER cable has an ampacity of 90 amps.
Under the 2008 NEC due to a change in 338.10(B)(4)(a) you are limited to the 60 degree column of Table 310.16 so the ampacity of #2 Aluminum SER cable is 75 amps.
I am assuming by the use of the term "subfeeding" the that feeder in question is not a main power feeder and Table 310.15(B)(6) would not apply.
Chris
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
2-2-2-4 AL, SE-R cable when the conductors are XHHW-2
Table 310.16
This cable is good for 90A.
Table 310.16
This cable is good for 90A.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Since 90 amps is listed as a standard size for a breaker in 240.6, I believe that you can not upsize to a 100 amp breaker.
- Location
- Logan, Utah
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
Supply houses around here have been supplying Al SER that way for so long, they cannot understand why it is not permitted.
Now that our area is going to the 2008 NEC, wait....
Now that our area is going to the 2008 NEC, wait....
- Location
- Logan, Utah
Under the 2008 NEC 250 Kcmil Aluminum SER cable has an ampacity of 170 amps at 60 degrees C. Using 240.4(B) you can only go up to a 175 amp breaker. Again this is for feeders that don't qualify as a main power feeder for a dwelling unit.
Chris
jwjrw
Senior Member
You are right. I was stating what other people are doing in the area by usine 4/0 and a 150 amp. The parts house had the change in se cable there last year and I overheard 250. I should of checked before I posted sorry.
Is that in lieu of SE 4/0 200A Main?
jwjrw
Senior Member
Yes that is what the hd rep told me.
- Location
- Logan, Utah
Not a problem.
I have just had heard some places had felt that 250 Kcmil SER cable was was Ok for a 200 amp feeder under the 2008 NEC by using 240.4(B). They just forgot that 240.6 lists a 175 amp breaker.
The 4/0 with a 150 amp breaker is the best solution that I have seen as well.
Chris
Jerseydaze
Senior Member
OK I'm confused I want to run a 200 amp main breaker to a 200 amp sub panel residential what size wire xhhw do i need 2008 Nec
Unfortunately, under the 2008 Code that has become an AHJ call.
Depending on how the authority looks at 310.15(B)(6), 215.2 and 338.10(B)(4), a 4/0 SER on an interior installation might be considered a 200 amp cable, or a 150 amp cable.
jwjrw
Senior Member
If its individual conductors 4/0 xhhw copper 2/0, alum 4/0
If its ser thats 300mcm I believe
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Are you talking about a feeder that feeds the entire load of the house?
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