Deratng overhead Alum. acsr

[tdjs]

What formula is used to size overhead alum.wire and is it that a smaller conductor can handle a bigger load since it is rated as open air conductor?

 

[jumper]

Not sure of what insulation ACSR is, but this may apply :

Table 310.17 Allowable Ampacities of Single-Insulated Conductors Rated 0 Through 2000 Volts in Free Air, Based on Ambient
Air Temperature of 30?C (86?F)

 

[rbalex]

ACSR (Aluminum Conducter Steel Reinforced) isn't insulated. Technically, it isn't NEC compliant and Table 310.17 doesn't apply because it isn't AA-8000 series electrical grade aluminum alloy conductor material. See 310.14.

That said, the formula in 310.15 (C) still works. This page lists the typical data. Note it lists ampere ratings rather than ampacities.