EMt conduit on the roof

[Stan Elmin]

Anyone know what the NEC says about the distance from the roof the the conduit has to be. I'm thinking 4" from s-tile to conduit.

Thanks

[Naptown]

That would most likely be safe provided the insulation on the wires is rated for 90C

[inetdog]

Anyone know what the NEC says about the distance from the roof the the conduit has to be. I'm thinking 4" from s-tile to conduit.

Thanks

The NEC does not tell you how far from the roof it has to be. But since the size of the conductors needed to carry the current will vary with the temperature around the wires, and since the conduit will be much hotter closer to the roof, it does give you an incentive.
The NEC tables for temperature adder (degrees above ambient temperature) for a rooftop conduit show that the added temperature decreases rapidly with height out to about 4". And beyond 6" the adder becomes very small.
As a result, the rule of thumb is to try to get the EMC at least 4" off the roof surface.
If you do not mind having to use large copper wires, then you do not have to worry about it as much.

Along the same lines, the critical value for spacing of panels off a roof to allow for cooling airflow seems to be about 4" too.