AL #2 for feeders

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squaredan said:
shouldnt we be using the 60 degree column for sizing 110.14(C)(1) (a) or do we know the terminals are rated 75 dergree then 110.14(C)(1)(a)(3) can be used..i have been told that all equiment is rated 75dergree terminals today...
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If it is not NM or SE cable, you could use the column that the wire is listed for ampacity to start derating, but cannot exceed the ampacity of the temp limitation of the terminal.

310.15(B)
Tables. Ampacities for conductors rated 0 to 2000 volts shall be as specified in the Allowable Ampacity Table 310.15(B)(16) through Table 310.15(B)(19), and Ampacity Table 310.15(B)(20) and Table 310.15(B)(21) as modified by 310.15(B)(1) through (B)(7).

The temperature correction and adjustment factors shall be permitted to be applied to the ampacity for the temperature rating of the conductor, if the corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisions of 110.14(C).
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tkb said:
If it is not NM or SE cable, you could use the column that the wire is listed for ampacity to start derating, but cannot exceed the ampacity of the temp limitation of the terminal.
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That is true also for NM and SE but final derated size can not be smaller than minimum 60C size for those cables.
 
The #2 alum on 100 amp OCPD is perhaps the most widely unenforced/unknown/overlooked thing in the electrical field. I dont think I have ever seen in my 14 years in the biz #2 alum on a 90 amp breaker - except on my work:) Example: I was ordering form my supply house (the one that I dont use that much) and asked for a Ch 290, didnt even have one, "what do you need that thing for??"
 
Most of the 2/2/2/4 around here is a 3-phase feeder type wire used for underground 3-phase feeders, it has three conductors labeled either 1,2,3 or A,B,C and the #4 has a yellow stripe, but is very common in this area to use for trailer feeders remarking the 3 or C as a neutral, and yes in almost all cases it is put on a 100 amp breaker when used as the feeder to a mobile home.
 
Most of the 2/2/2/4 around here is a 3-phase feeder type wire used for underground 3-phase feeders, it has three conductors labeled either 1,2,3 or A,B,C and the #4 has a yellow stripe, but is very common in this area to use for trailer or out building feeders remarking the 3 or C as a neutral, and yes in almost all cases it is put on a 100 amp breaker when used as the feeder to a mobile home.
 
electrofelon said:
The #2 alum on 100 amp OCPD is perhaps the most widely unenforced/unknown/overlooked thing in the electrical field. I dont think I have ever seen in my 14 years in the biz #2 alum on a 90 amp breaker - except on my work:) Example: I was ordering form my supply house (the one that I dont use that much) and asked for a Ch 290, didnt even have one, "what do you need that thing for??"
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I use QO290's all the time. Mostly for 10hp single phase motors. Supplier has them in stock and they are same price as 100's. That happens to be what Sq. D recommends for that size of motor. NEC says it could easily be a 125. Never have nuisance trip problems with them
 
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