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”)	33	60
Above 13mm (1/2”) - 90mm (3-1/2”)	22	40
Above 90mm (3-1/2”) - 300mm (12”)	17	30
Above 300mm (12”) - 900mm (36”)	14	25