what type of conduit to use on rooftops of rubber and types of raised blocking availa

[wbculley]

I have a job installing light fixtures (not luminaries I'm American) on a building with a rubber roof. I am considering NMFlex with #10 wire. Temp max probably 115 in Day.
Lights won't be on til nite probably 80 atextreme temp. In WV
Also what type of blocks risers etc do they make to raise conduit above rubber roofs.

 

[cadpoint]

I'm not sure what your referencing by the use of "NM" with, if it's Article 382 that would be a no go.

I'd run with a minimum of EMT with compression fittings that are ususally colored coded denoting outdoor usuage! One could use T's and EL's and maybe run on the side of the parapit wall above the sealed roof and below the parapet cap.

My question is how or who is responsible for the possible roof penetration? Last I heard it was 1K per hole, only the installer or their agent can do it! ?

 

[220/221]

I use EMT. For support, I use PVC pieces, tacked down with caulk and two hole straps.

I always double/triple up on support, installing it 12" on each side of couplings and at the 5' mark.


They do make burly rubber blocks with unistrut built in. I believe they are about $20 each.

 

[satcom]

You have to follow the roofing manufactures advice on how the support is attached and type of support is recommended not following the manufactures instructions can cost you a small fortune if roof damage developed
We use rigid conduit on roofs EMT turns into a rust bucket and can be damaged easy after a short time we get plenty of work replacing EMT roof installations.

 

[stevebea]

I have a job installing light fixtures (not luminaries I'm American) on a building with a rubber roof. I am considering NMFlex with #10 wire. Temp max probably 115 in Day.
Lights won't be on til nite probably 80 atextreme temp. In WV
Also what type of blocks risers etc do they make to raise conduit above rubber roofs.

We always use B-Line Dura-Blok for running conduit on a roof but they are not cheap at $20 a block.

 

[renosteinke]

I run EMT, saving 'flex' for where I need it - for example, the last section to a hood fan (sisnce the fan is removed for cleaning the duct).

I use wood for my 'sleepers.' Untreated 2x4's work well on a 'clear' roof. If there are any other things on the roof, you will want to use 4x4's. I cut them 12" long, and take care to use screws that will not penetrate or split the wood.

Why so large? Well, too short and the wood will split. It also helps to have some weight to hold the pipe in place while your mastic sets; roofs are not nearly as flat as you think.

I do find it necessary to support the pipe more often than 'code minimum.' That is, on either side of a 90, as well as on either side of each coupling.

The wood is attached to the roof with ordinary roofing cement ("Blackjack")

A special note regarding the grey rubber roofing (EPDM): BEFORE you apply mastic, it is likely the roofing guy will want to add a layer of rubber under your sleepers. He'll also likely lay a 'path' to your equipment.