Roof top curb penetrations??

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electriciansrule123

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I need to power 3 roof top exhaust fans. Flat, commercial grade rubber roof. The EF's are sitting on top of 2 feet of vertical curb/duct that is also rubber roofed.

How do I penetrate the curb/duct? Liquid tight and____? :?
 
These probably need a service switch. I would come up between the curb and the duct. Mount a box on the curb as high as necessary for winter snow. Seal tight up to the fan. The fans usually have a conduit entry.
 
Gotcha. Typically I would run my MC inside the curb. Between the curb and the duct. However not in this instance. Cant be done as the duct and curbs are finished and installed. Well besides the power...

I have to come across the roof from a existing roof penetration with liquid tight. I just wasn't sure if there was a spec way to penetrate the curbs. Like some special connector or something.

What happened is the elevator contractor added EF's. These EF's are/were not in our contract. Well as one would expect the GC now demands that these EF's be powered constant normal power. Not emergency power.

I guess I could try and sneak something between the EF and the curb and the top of the curb. I was just hoping there was a premade connector or sleeve or something. A Meyers hub? :)

TY for your time and help and have a great day!!
 
flatlander said:
These probably need a service switch. I would come up between the curb and the duct. Mount a box on the curb as high as necessary for winter snow. Seal tight up to the fan. The fans usually have a conduit entry.
Click to expand...

Oh yeah. Service switch is under the top hood. Just a 120v single pole sw is all it is.

Although this might be a solution you have suggested. How about I mount a weather tight bell box and go through the back of it into my curbs?? Yeah it won't be weather tight if I got through the back but I could caulk it and it will look cleaner!

BRILLIANT Flatlander! That's thinking with your dip stick!! TY!
 
All these commercial roof come with some sort of warranty.

Do not penetrate the roof or you own it.

If you absolutely have to go through the membrane, talk to the building owner or management and hire the roofing company that covers the warranty.

This will save you a ton of headaches should your penetrations leak.

Joe,
 
Joe Villani said:
All these commercial roof come with some sort of warranty.

Do not penetrate the roof or you own it.

If you absolutely have to go through the membrane, talk to the building owner or management and hire the roofing company that covers the warranty.

This will save you a ton of headaches should your penetrations leak.

Joe,
Click to expand...

Thanks Joe,

Yeah the roofers warranty... Sigh. I know they are being hard arses about the warranty as it is on this job. Seems the mechanical guys made a penetration after they signed off on it. Someone added some heat tape to a water chiller unit on the roof top. They shoved it down through and existing witches hat and the roofers are NOT happy about it. They tried to say it was us sparkies but none of our guys ran that heat tape. It was one of the mech guys.

Maybe I can find some way to penetrate the actual exhaust fan unit?...

TY for everyones time and have a GREAT weekend!
 
I had a rubber roof with three kitchen exhaust fans on it. I wish I had a picture because its so much easier to show.

The roofers put down a approved ( by goodyear ) 4x4 metal flange around the mc coming through the roof. They filled it with caulk and put a flat cap on it.

They put caulk or some sort of sealant on the cap and I screwed a 6x6 pvc rain tight box on top of the cap with my wire coming right through the bottom.

I was happy, and they were happy that their warranty conditions were met.

Don't you touch that roof Ricky Bobby.
 
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