810.20(B) Combustible Material definition needed

[goillinisparky]

I had a student ask about 810.20(B) saying that "the antenna discharge unit shall not be located near combustible material." What defines combustible in this case? Isn't wood "combustible", and if so, does that mean that the discharge unit cannot be installed on wood siding?
I must say, he had me on that one. I am not sure what they are referring to.
A dictionary defines combustible as "able to catch fire and burn easily." Wood can catch fire and burn, but not what I would call "easily."
Anybody know?
Thanks for the help.

 

[BackInTheHabit]

It doesn't have to be just wood. It can also be a vapor. If vapor conditions are present, Article 500 Hazardous (Classified) Locations need to be met as well.

Also look at 810.57 Antenna Discharge Units - Transmitting Stations

K8MHZ may have some input on this.

 

[Buck Parrish]

I had a student ask about 810.20(B) saying that "the antenna discharge unit shall not be located near combustible material." What defines combustible in this case? Isn't wood "combustible", and if so, does that mean that the discharge unit cannot be installed on wood siding?
I must say, he had me on that one. I am not sure what they are referring to.
A dictionary defines combustible as "able to catch fire and burn easily." Wood can catch fire and burn, but not what I would call "easily."
.

In this case, I would say "Near" is the key word here. A listing by UL should list the mounting methods and requirements.
The metal housing probably has some areas in the back that are raised a 1/2 in. They are generally where the screw holes are.This would not allow the case to lay right up against the wood.

 

[goillinisparky]

Thanks guys.