Determining Ampacity

[jtsauce29]

Do you consider the size of conduit when calculating ampacity? i.e. # 12 THHN in a 2-1/2" conduit with 4 existing current carring conductors.

 

[iwire]

Do you consider the size of conduit when calculating ampacity? i.e. # 12 THHN in a 2-1/2" conduit with 4 existing current carring conductors.

No, the NEC does not take pipe size into account.

 

[benaround]

jt,

There are different rules for 'nipples' or conduits 24" or less in length, just guessing

maybe that is what the 2 1/2" is for ?

 

[Twoskinsoneman]

jt,

There are different rules for 'nipples' or conduits 24" or less in length, just guessing

maybe that is what the 2 1/2" is for ?

I think the question being asked here is does the cross-sectional area of the conduit affect the ampacity of the conductors? The answer being no.

 

[benaround]

I think the question being asked here is does the cross-sectional area of the conduit affect the ampacity of the conductors? The answer being no.

Thanks for that info ?

 

[Jim W in Tampa]

First you select wire size after derating and voltage drop , the select pipe size. Also look at length and bends as your the guy that gotta pull it.

 

[celtic]

Do you consider the size of conduit when calculating ampacity?

No, the NEC does not take pipe size into account.

But do YOU?