kenaslan
Senior Member
- Location
- Billings MT
Situation:
I have 12 each 100Hp 460V motors. Ambiient air temp is 114F. Cables to be 3/C 2/0 XHHW-2. Uncovered Ladder type cable tray.
NEC 392.80(A)(1)(c) states
"Where multiconductor cables are installed in a single layer in uncovered trays, with a maintained spacing of not less than one cable diameter between cables, the ampacity shall not exceed the allowable ambient temperature corrected ampacities of multiconductor cables, with not more than three insulated conductors rated 0 through 2000 volts in free air, in accordance with 310.15(C).
My question is, what is the derating for conductors CLOSER than one cable diameter between cables?
I have 12 each 100Hp 460V motors. Ambiient air temp is 114F. Cables to be 3/C 2/0 XHHW-2. Uncovered Ladder type cable tray.
NEC 392.80(A)(1)(c) states
"Where multiconductor cables are installed in a single layer in uncovered trays, with a maintained spacing of not less than one cable diameter between cables, the ampacity shall not exceed the allowable ambient temperature corrected ampacities of multiconductor cables, with not more than three insulated conductors rated 0 through 2000 volts in free air, in accordance with 310.15(C).
My question is, what is the derating for conductors CLOSER than one cable diameter between cables?