# Rooftop Deck



## 99cents (Aug 20, 2012)

akheilman said:


> Hey guys,
> 
> A 32-story high rise in Philadelphia had existing wood decks on the roof that needed to be removed for roof replacement. The roof has been replaced, and the decks reframed. Now they want to reinstall the receptacles and lighting that were around the perimeter. The original wiring is exposed UF cable.
> What is the appropriate wiring method for this? I doubt UF is code compliant. Is PVC allowed?
> ...


What does the code book say?


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## Kevin (Feb 14, 2017)

I'd say teck cable but I hear that doesn't exist down south. Something else rated for that will have to be used. A code book can be useful for looking that stuff up...

Sent from my Samsung using Tapatalk


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## varmit (Apr 19, 2009)

The only NEC limitation could be the "subject to physical damage" clause.

Your state fire codes may not allow PVC in/on a high rise building.


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## sbrn33 (Mar 15, 2007)

I can't even imagine any type of romex is going to be allowed. I would EMT it but maybe some kind of wet location MC cable might be allowed.


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## macmikeman (Jan 23, 2007)

I guess nobody here has ever heard of liquid tite flexible cable. And wp boxes and in use covers. 

Is this op even a electrician?


Haha, I called it cable..... conduit


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## joebanana (Dec 21, 2010)

Can't go wrong with EMT, and THHN/THWN.


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## 99cents (Aug 20, 2012)

macmikeman said:


> I guess nobody here has ever heard of liquid tite flexible cable. And wp boxes and in use covers.
> 
> Is this op even a electrician?
> 
> ...


Aren’t in-use covers only required for resi?


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## akheilman (Jun 28, 2011)

PVC and/or carflex would be great, but I’m not 100% sure about the use of nonmetallics on the exterior of a class 1/2 building.


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## HackWork (Oct 2, 2009)

Small diameter PVC is too homeownerish for exposed work on a high rise building. If you're not near the saltwater, just use EMT.


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## splatz (May 23, 2015)

If you use UF rated for UV exposure, and it isn't subject to physical damage, I don't see anything in article 340 that would rule out UF. It doesn't have the restrictions based on building type that you have for NM. 

If you can hide it, or it doesn't need to look nice, you could do it in PVC and sealtight. If it needs to look nice, EMT.


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## MechanicalDVR (Dec 29, 2007)

+1 for macmike's post if it's down and dirty.

EMT and thwn if it's a decent place.


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## kb1jb1 (Nov 11, 2017)

If using EMT then you need to use the weather rated compression couplings and connectors. They are not the standard compression connectors / couplings. They must be labeled for wet locations. I prefer to use Aluminum rigid conduit. A 32 story building with a wood roof I would question. It must be a very old building. Does it meet the fire codes or did they replace it without permits? But then I live in NY.


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## macmikeman (Jan 23, 2007)

Rooftops can be brutal on both pvc and emt. One turns brown after time and starts to crack apart- pvc - from sun . The other gets rusted thru unless painted early on and at regular intervals. Liquid tite flexible steel conduit lasts decades up there.


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## Easy (Oct 18, 2017)

HackWork said:


> Small diameter PVC is too homeownerish for exposed work on a high rise building. If you're not near the saltwater, just use EMT.


I totally agree. EMT would be the best option. PVC would be sagging in a short amount of time. Heat from the Sun and cold weather both effect PVC. Seal-tight flex in long runs would look bad and probably cost more. I have seen the effects of salt air and other chemicals on EMT and even Rigid but PVC is just too fragile. I think as long as code allows it EMT would be the simplest install. I have also seen installs that are real close to the Beach where certain inspectors won't allow it to be used. Only rigid outside or even coated RMC. I would call the city and ask first.


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## Easy (Oct 18, 2017)

kb1jb1 said:


> If using EMT then you need to use the weather rated compression couplings and connectors. They are not the standard compression connectors / couplings. They must be labeled for wet locations. I prefer to use Aluminum rigid conduit. A 32 story building with a wood roof I would question. It must be a very old building. Does it meet the fire codes or did they replace it without permits? But then I live in NY.


Aluminum Rigid is so nice to work with but it seems like it turns all white and powdery looking if salt gets to it. That's not to say it's not a good solution. The treads lock up after time from corrosion. NoLox or some anti-seize lubricant works to cure that but I just am not sure if it's code compliant to actually do that. Probably fine if you run a EGC with your hots rather than use the raceway as your EGC. I think most of us pull in grounds anyways so it's probably no big deal.


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## Easy (Oct 18, 2017)

99cents said:


> Aren’t in-use covers only required for resi?


Good question. I install them out of fear of getting red tagged. Oh yes and receptacles must have have WP stamped on them in big letters. Supersized the inspector let me only use WP and not WP/CP receptacles. They do make some nice low profile in use covers. Metal ones too. :sad: I am just not totally sure about the actual requirement but if it was a public place I would say yes for sure. Bummer


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## Easy (Oct 18, 2017)

99cents said:


> What does the code book say?


I'm not to good with code books as mine is vintage 1999. I have never worked on any roof top electrical systems of buildings over 7 stories. All of them had Mostly EMT and some Rigid or coated Rigid in manufacturing facilities with chemical processes. Something that should also be consider is Temperature Correction on roofs. Don't ask me too much about that as it applies to types of conduits. It's probably something to be very concerned about if you work on roof tops in Las Vegas.


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## Easy (Oct 18, 2017)

akheilman said:


> Hey guys,
> 
> A 32-story high rise in Philadelphia had existing wood decks on the roof that needed to be removed for roof replacement. The roof has been replaced, and the decks reframed. Now they want to reinstall the receptacles and lighting that were around the perimeter. The original wiring is exposed UF cable.
> What is the appropriate wiring method for this? I doubt UF is code compliant. Is PVC allowed?
> ...


How does the wiring penetrate the roof? Is it EMT? It can't be UF cable. No one would ever destroy a 32 story building with UF cable. What is the roof finish? That would be something I would think about as well. If it's a flat roof you should set up unistrut or some type of support system for the conduit and get with the roofers for a good product that will adhere to that surface. Unless they are no longer available. Or you may be just anchoring to the para pit wall and not the roof system. You don't want your conduit setting in water.


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## macmikeman (Jan 23, 2007)

I guess nobody here has ever heard of liquid tight flexible metal conduit.


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## Easy (Oct 18, 2017)

Yes Liguid tight metal flex would work for some simple lights around the perimeter of the roof. Maybe a low voltage lighting system. 24v or 12v and run no conduit. 
I would stay with 120 volts or what ever the voltage was supplying the old lights 277? and use EMT and Seal tight METAL flex as needed.


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## Tonedeaf (Nov 26, 2012)

it's a 32 story building *WORTH 10's of MILLIONS OF DOLLARS*

don't **** it up with carflex and PVC

I would use aluminum rigid or if they have the bucks OCAL


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## Easy (Oct 18, 2017)

There is an urban legend that EMT an not be used outside. I have herd it from several electricians and even electrical engineers. It seems strange that they make rain-tight fittings for EMT. That kind of contradicts the legend. In any case if it's something that will be inspected just call the city and ask or get stamped drawing from an RE or EE. You don't want to do the job twice. Also get proper supports to elevate the runs about the roofing material so they can repair or re-coat the roof next time.


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## MechanicalDVR (Dec 29, 2007)

Easy said:


> *There is an urban legend that EMT an not be used outside. *I have herd it from several electricians and even electrical engineers. It seems strange that they make rain-tight fittings for EMT. That kind of contradicts the legend. In any case if it's something that will be inspected just call the city and ask or get stamped drawing from an RE or EE. You don't want to do the job twice. Also get proper supports to elevate the runs about the roofing material so they can repair or re-coat the roof next time.


Never heard that legend where I've worked.

It would be said the millions of miles that has been run would prove it wrong.


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## Easy (Oct 18, 2017)

"Never heard that legend where I've worked.

It would be said the millions of miles that has been run would prove it wrong."

Perhaps it started right before they transitioned from EMT compression fittings to actual rain tight fittings. I would run EMT all day long outside. Just keep it away from soil. I really don't think salt air is a problem either unless you are right next to the ocean. 
358.12 *Uses Not Permitted*
>Where subject to severe physical damage.
> In cinder concrete or cinder fill where subject to permanent moisture, unless protected on all sides by a layer of non cinder concrete at least 2 in. thick, or unless
the tubing is at least 18 in. under the fill.
>Not permitted in hazardous locations.
>For the support of luminaires or other equipment
>Where practicable, dissimilar metals in contact anywhere in the system shall be avoided to eliminate the
possibility of galvanic action.
Exception: Aluminum fittings on steel EMT and steel fittings on aluminum EMT are permitted.
No mention of outdoor use.


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## sbrn33 (Mar 15, 2007)

I forgot to ask. Is it a big deck?


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## Easy (Oct 18, 2017)

I wonder if the aviation lights are required. I don't actually know the rules on that but I have seen them on buildings as low as 4 stories. Probably depends on how close you are to the air port.


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## lisa85goss (Aug 27, 2019)

In most cases, rooftop decks are nothing more than raised patios. You can enter them through the second floor of your property, allowing you to overlook your lawn and neighborhood. From there, you can also enjoy beautiful views of sunsets and moon rises, and scenic views of the surrounding landscape.


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## Easy (Oct 18, 2017)

lisa85goss said:


> In most cases, rooftop decks are nothing more than raised patios. You can enter them through the second floor of your property, allowing you to overlook your lawn and neighborhood. From there, you can also enjoy beautiful views of sunsets and moon rises, and scenic views of the surrounding landscape.


And watch monkeys chase Dorthy while you sip on some Vodka.... but how would this help to answer the question posed. "What type of ELECTRICAL conduit is code legal on a high rise building" I'm interested to learn what is acceptable for my own knowledge.

I'm sure there are several methods that would work. RMC, IMC, EMT and short runs or seal-tight flex would most likely all be acceptable. Who knows maybe it requires coated rigid in some cities. I would like to learn the actual code requirements for a roof top of a 32 story building are. 
If I had access I would probably throw parties or at least invite people to hang out. I bet code could be real strict in certain areas of the US, Canada or England.


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## kb1jb1 (Nov 11, 2017)

I am 95% sure NYC does not allow EMT outside a building. I worked for a contractor over 30 years ago and we had to use rigid on the outside for parapet lighting. Other cities might have same requirements.

There is PVC coated MC cable ( also called parking deck cable ). Special fitting have to be used.


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## macmikeman (Jan 23, 2007)

Roof top decks are fabulous if you live on Ke Nui Road. Fabulous.


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