NEC ampacity and ambient temperature adjustment
NEC ampacity and ambient temperature adjustment
(OP)
The NEC (NFPA 70) has an equation for converting cable ampacity at 40 C to ampacities at different ambients (Section 310). The equation has a Delta TD = Dielectric Loss Temperature Rise. Where can I find values for this factor? I suspect it's in the IPCEA document referenced, but I don't have that.






RE: NEC ampacity and ambient temperature adjustment
RE: NEC ampacity and ambient temperature adjustment
RE: NEC ampacity and ambient temperature adjustment
RE: NEC ampacity and ambient temperature adjustment
RE: NEC ampacity and ambient temperature adjustment
Actually, ΔTD is much simpler to calculate that YC and RCA in the formula. What are you using for these? For 15 kV cable and below, the dielectric loss is low and you can probably safely assume ΔTD=0
RE: NEC ampacity and ambient temperature adjustment
I'm not using YC or RCA. I'd need those if I was trying to calculate ampacity from scratch. I'm just trying to adjust for an ambient temperature higher than 40 C. I'm using the equation in the NEC 310-60(C)(4)
RE: NEC ampacity and ambient temperature adjustment