Feeding Rooftop Equipment

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Alwayslearningelec

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NJ
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Estimator
In new construction how is roof top equipment usually fed? I know it depends if it is a poured slab or pre-cast whether you sleeve or core. Do you sleeve or core? Does someone else provide an opening for conduits?

Thanks.
 
Sometimes someone else does it........today I think most equipment is wired up thru the equipment, thru the curb and such, eliminating any penetrations outside of the footprint of the equipment.
 
Sometimes, they provide what's called a 'pitch pocket', which is a sleeve through the roof that is filled with pitch once the necessary runs are passed through it. You don't want to miss the time window to pass your power cabling/raceway through it.
 
horsegoer said:
Sorry I'm a bit confused. So is there a penetration through the roof?
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When ran thru the equipment.......no, no penetration. Some RTU's.....have chases to install your raceways thru to eliminate penetrations, potential leaks......
 
Thanks Larry. I have heard of that. I assume that would be in the spec as to whther or not they(roof contractor or whomever) provides that.

What is pitch?
 
Sorry Larry, I google imaged it and found some information. I would like to thank everyone for bearing with my questions and helping me out.
 
horsegoer said:
What is pitch?
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Black goopy stuff, like tar. Ever hear of "pitch black?"

Side note: When my son was little, he thought 'pitch' meant 'very,' and described something as 'pitch white.'
 
barbeer said:
When ran thru the equipment.......no, no penetration. Some RTU's.....have chases to install your raceways thru to eliminate penetrations, potential leaks......
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When it comes to potential leaks, you want to be sure, your insurance covers the risk of roof penetrations, one leak can cost you the farm, not many contractors are covered for roof openings.
 
horsegoer said:
Sorry I'm a bit confused. So is there a penetration through the roof?
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sometimes the roofers will put a witch's hat or a cow's utter for roof penetrations, but a lot of rtu's come with a knockout inside the unit, so u can go through the apron into the unit.
 
what is usually the case is if it is a RTU there is usually a knockout that goes right on top of the curb and you will sometimes need to be there when they set it to knock it out and drill a hole in the roof if it is just membrane. now if it is a split system and you have an air handler or condenser on the roof than most that I have seen dont have the knockout for the curb and you have to penetrate a seperate hole. but beware because usually if you cut a whole in the roof it voids the roofers warranty so you may want to check with the gc and get the roofer there to cut and set the pitch pocket.
 
pitch black

pitch black

LarryFine said:
Black goopy stuff, like tar. Ever hear of "pitch black?"

Side note: When my son was little, he thought 'pitch' meant 'very,' and described something as 'pitch white.'
Click to expand...

they sometimes call them witch hats. there black have rubber knock outs on the top and a wide brim to seal to the rubber roof.
 
satcom said:
When it comes to potential leaks, you want to be sure, your insurance covers the risk of roof penetrations, one leak can cost you the farm, not many contractors are covered for roof openings.
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What do you do if you have to install or replace a service mast thru the eave on a building?

Call a roofer?

I've always just cut the hole myself and installed a roof flange.

Never thought about it much...it's good point to ponder.
I need to read my insurance policy again.

steve
 
I did a resturant last summer and made my own pitch pocket and just put that Karnak tar all around it... trust me it won't leak if you put it on nice and thick.
Also instead of using that expensive strut with the foam block on the bottom, I just cut treated lumber and screwed my strut to that to run to all of the exhaust fans and condensers.
 
Pitch pockets and witches hats are two different methods.

In general pitch pockets are used on asphalt roofs

79_small.jpg


Pitch Pocket
Pitch Pockets are flanged, open-bottomed, metal containers, placed around columns or other roof penetrations. They are filled with hot bitumen or flashing cement in order to seal the joint, thus blocking penetrations of the roof.
Pitch pockets are easy to install. You can simply open it up and wrap it around the roof penetration. All that is required is some light hammering to the corner lock in order to hold it together. This quick installation provides a water tight seal.

B&B Pitch Pockets are available with or without soldered corners
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Witches hats are normally used with a rubber roof system.

flatseal-flat-roof-flashing-b.jpg


As the others have said any normal RTU will have a place to come up inside. If your lucky it could come with a built in disconnect switch and a built in GFCI receptacal. It just depends how they are specified by the engineer.
 
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