Ambient temperature compensation
- Thread starter rbb
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Ambient temperature compensation
You don't.
You don't.
friebel
Senior Member
- Location
- Pennsville, N.J.
Re: Ambient temperature compensation
rbb, asked the question, "How do you apply ambient temperature compensation to Table 310.15(B)(6).
The Moderator Charlie b's answer was, "You don"t.
My question to Charlie b is, "Why don't we use the temperature compensation for the Table 310.15(B)(6)".
rbb, asked the question, "How do you apply ambient temperature compensation to Table 310.15(B)(6).
The Moderator Charlie b's answer was, "You don"t.
My question to Charlie b is, "Why don't we use the temperature compensation for the Table 310.15(B)(6)".
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Ambient temperature compensation
The simple answer is that the book does not tell you to compensate the service or feeder ampacities for temperature. But I think the real reason is that the table is not a table of ampacities. It says that for a 100 amp service, you can use a #4 copper. It does not say that a #4 is good for an ampacity of 100 amps under a given ambient temperature and a given installation method (e.g., underground versus overhead). Also, there is no question of de-rating for having more than 3 current-carrying conductors in a raceway, since the table is limited to 3-wire systems.
The simple answer is that the book does not tell you to compensate the service or feeder ampacities for temperature. But I think the real reason is that the table is not a table of ampacities. It says that for a 100 amp service, you can use a #4 copper. It does not say that a #4 is good for an ampacity of 100 amps under a given ambient temperature and a given installation method (e.g., underground versus overhead). Also, there is no question of de-rating for having more than 3 current-carrying conductors in a raceway, since the table is limited to 3-wire systems.
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