Question

What is the smallest size conductor allowed to be used in a building for branch circuits?

What is the smallest size conductor allowed to be connected in parallel?

There are three current-carrying conductors in a raceway that is to be installed in an area with an ambient temperature of 86°F. It is necessary to

There are six current-carrying conductors in a raceway that is to be installed in an area with an ambient temperature of 96°F. It is necessary to

Answer 1

1. The minimum size of conductor permitted to be used in any building for branch circuits ( for under 600V operation) is 14 AWG.

2. Parallel conductors must not be smaller than 1/0 AWG (aluminium or copper conductor).

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for question 3 and 4.

As per NEC 310.15(A)(3), When the number of conductors in a raceway exceeds 3 and ambient temperature is other than 30C(or, 86 F) then we apply both ambient temperature correction factor and adjustment factor for current carrying conductors.

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3. The ambient temperature is 86F and number of conductors in raceway is 3. So it is not necessary to apply Correction factor and adjustment factor to find the maximum allowable ampacity.

4. The ambient temperature is 96F(above 86F0 and number of conductors in raceway is 6(exceeds 3). So it is necessary to apply Correction factor and adjustment factor to find the maximum allowable ampacity.