• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

NEC 310.15.B(17)

anbm

Senior Member
Location
TX
Occupation
Designer
When we run (4) single conductors (not in conduit or cable) for three phase, 4 wire circuits, we size the
the wire based on NEC table NEC 310.15.B(17), correct?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
These conductors are in free air? If so then the use of that table has to comply with the conditions of use in 310.17 from the notes at the bottom of the table.

Notes:
1. Section 310.15(B) shall be referenced for ampacity correction factors where the ambient temperature is other than 30°C (86°F).
2. Section 310.17 shall be referenced for conditions of use.
*Section 240.4(D) shall be referenced for conductor overcurrent protection limitations, except as modified elsewhere in the Code.
.

310.17 Ampacities of Single-Insulated Conductors in Free Air.
The ampacities shall be as specified in Table 310.17 where all of the following conditions apply:
(1) Conductors are rated 0 volts through 2000 volts.
(2) Conductors are rated 60°C (140°F), 75°C (167°F), or 90°C (194°F).
(3) Wiring is installed in a 30°C (86°F) ambient temperature.
 
Top