Temp Adjustment Conduit on Roof

When conduit is run on a roof top studies have shown the conduit will heat. The following table will provide a temperature adder based on the conduit mounting height. This is used to adjust the current carrying capacity of conductors.

Distance above roof
to bottom of conduit
Temperature
Adder (C)
Temperature
Adder (F)
0 - 13mm (1/2")3360
Above 13mm (1/2") - 90mm (3-1/2")2240
Above 90mm (3-1/2") - 300mm (12")1730
Above 300mm (12") - 900mm (36")1425