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
Adder (C)
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