emt conduit on rooftop

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Joed384 said:
So now I started an argument and I'm still unsure on which is the best method to go with.
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If the local jurisdiction does not have specific requirements then I think both will work. EMT may degrade faster.

Use PVC with more support.
 
as i have already mentioned, choose wisely. yeah yeah, i know, its a rooftop, doesnt really matter, its still subject to physical damage.
Article 352 of the Code identifies PVC Schedule 80 conduit for use in exposed areas subject to physical damage and also identifies PVC conduit Schedule 40 for use in exposed areas not subject to physical damage where the raceway is identified for the application. Yet, some electrical installers resist those applications. “You need to install to the Code and how the Code is written,” says Glorieux. “But even Schedule 80 isn't all that strong and is open to abuse. Rigid metal conduit and regular electrical metallic tubing (EMT) will withstand a lot more physical abuse than PVC. The thought that metal conduit is always there as your last defense for ground faults is nice as well.”
Although John Schmuck, electrical reliability engineer for Lyondellbasell Industries, Corpus Christi, Texas, is not an electrical contractor, his professional background has made him aware of the hazards associated with improperly exposed PVC conduit. “Here in South Texas, PVC that is exposed to the sun gets brittle, and it is not uncommon to see broken PVC,” he says. “I see it most often on stub-ups for signs or lighting where it is subject to being hit by lawn mowers or vehicles. The broken conduit exposes the conductors and presents an electrocution hazard, so I don't believe it is a suitable material for this service.”
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peter d said:
Yeah, that must be it. :happyno:
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hmmm, well, if you used stainless you wouldnt have corrosion issue. if you have corrosion issue using metal then you used the wrong type of metal :thumbsup:
 
FionaZuppa said:
well, perhaps you chose the wrong type of metal :thumbsup:


art 353, what about it??
HDPE will eventually surpass what PVC can do in all regards. HDPE is also more environmentally better to make than PVC.

for the OP, perhaps run PVC and be done with it. if you want to add a little extra PVC protection, spray the top with gray acrylic spray or a clear acrylic primer spray. this adds some additional UV protection, but certainly not a requirement.
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What HDPE may become has nothing to do with the here and now- it cannot be exposed and is of no use to the ops app.

FionaZuppa said:
as i have already mentioned, choose wisely. yeah yeah, i know, its a rooftop, doesnt really matter, its still subject to physical damage.



hmmm, well, if you used stainless you wouldnt have corrosion issue. if you have corrosion issue using metal then you used the wrong type of metal :thumbsup:
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And if corrosion was guaranteed to be a problem, maybe he could use rigid or pvc and not needlessly waste $$$ on ss conduit.
 
FionaZuppa said:
as i have already mentioned, choose wisely. yeah yeah, i know, its a rooftop, doesnt really matter, its still subject to physical damage.



hmmm, well, if you used stainless you wouldnt have corrosion issue. if you have corrosion issue using metal then you used the wrong type of metal :thumbsup:
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Remember, it is stain-LESS steel. Not doesn't-stain-at-all steel.

Stainless steel can still corrode.
 
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