Distance from rubber roof to conduit

[JJWalecka]

Is there a minimum distance a raceway feeding HVAC equipment must be above a rubber roof

I have always used sleepers but recently saw uni strut mounted directly to the rubber roof to support the raceway. Which would only give 1 5/8 space

Thanks for your time

 

[rc/retired]

I don't see a minimum or maximum height anywhere in the code.

Ron

 

[Rick 0920]

There is a temperature adder for raceways above the roof for ampacity of conductors above roofs. Below 7/8" you would add 60 degrees F. to your ambient. I agree with RC, there is no min./max. noted anywhere.

 

[JJWalecka]

There is a temperature adder for raceways above the roof for ampacity of conductors above roofs. Below 7/8" you would add 60 degrees F. to your ambient. I agree with RC, there is no min./max. noted anywhere.

Do you have the code article that states 7/8. Or point me in the right direction to look it up. Thanks for your time

 

[don_resqcapt19]

310.15(B)(2) in the 2023 code and 310.15(B)(3)(c) in older codes. Note the original rule was 7/8" but that was based on the dimensions of one major brand of strut type supports. The substantiation for the change to 3/4" said:

"The choice of dimension was obviously made to allow for standard shallow strut configurations. However, although it corresponds to one major brand (Unistrut), it inadvertently excludes most others. For example, B-Line and Superstrut use 13/16-inch, and Kindorf uses ¾ inch."

 

[JJWalecka]

310.15(B)(2) in the 2023 code and 310.15(B)(3)(c) in older codes. Note the original rule was 7/8" but that was based on the dimensions of one major brand of strut type supports. The substantiation for the change to 3/4" said:

"The choice of dimension was obviously made to allow for standard shallow strut configurations. However, although it corresponds to one major brand (Unistrut), it inadvertently excludes most others. For example, B-Line and Superstrut use 13/16-inch, and Kindorf uses ¾ inch."

Thanks for your time