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 |
