PVC use indoors

[ron]

I have always specified metallic conduit, metallic tubing, and metallic cabling for commercial use indoors.

Is there a code reason we couldn't use rigid PVC (Article 352) for feeders and branch circuits concealed in a commercial building?

 

[ActionDave]

There are some fire code restrictions I bet. One of the reasons not to use PVC indoors is the strapping and supporting rules require so many straps its easier to use metal conduit. And even when you strap as much as you should, most folks don't, you still end up with saggy, droopy pipes everywhere.

 

[qcroanoke]

There are some fire code restrictions I bet. One of the reasons not to use PVC indoors is the strapping and supporting rules require so many straps its easier to use metal conduit. And even when you strap as much as you should, most folks don't, you still end up with saggy, droopy pipes everywhere.

+1
What Dave said.

 

[ron]

I wouldn't doubt there is a fire code rule, maybe similar to the NEC restrictions we have for NM cable in commercial buildings, but I'm at a loss to find them.

 

[jaggedben]

I have always specified metallic conduit, metallic tubing, and metallic cabling for commercial use indoors.

Is there a code reason we couldn't use rigid PVC (Article 352) for feeders and branch circuits concealed in a commercial building?

Looking at your location, I wouldn't be surprised if they had a local amendment that was much more restrictive than the NEC. The large city that I live in prohibits PVC except where embedded in concrete.

 

[raberding]

probably not allowed in plenums

 

[steve66]

No, definitely not allowed in air plenums.

But if its a non-plenum space, and there are PVC plumbing pipes, I'm not sure why PVC electrical wouldn't be allowed.

 

[steve66]

Also, not in any assembly spaces per 518, unless you want to encase it in concrete.

 

[GoldDigger]

No, definitely not allowed in air plenums.

But if its a non-plenum space, and there are PVC plumbing pipes, I'm not sure why PVC electrical wouldn't be allowed.

Well, one small difference is that PVC plumbing pipes are not likely to be ignited by a fault inside them and are usually cooled against external heat sources by the liquid inside them.

 

[A/A Fuel GTX]

Well, one small difference is that PVC plumbing pipes are not likely to be ignited by a fault inside them and are usually cooled against external heat sources by the liquid inside them.

A good percentage of them are for venting and have no liquid in them.

 

[Carultch]

probably not allowed in plenums

The meaning of the word plenum is a little confusing.

To clarify, no wiring that is not directly necessary for the functionality of the air handling system is allowed in physically constructed ducts or plenums. Examples of such wiring are air temperature/speed sensor wiring or fan power/control wiring, that has no other option other than to be in the physically constructed duct/plenum. To contrast with physically constructed plenums, a plenum space, built with building walls and ceilings instead of duct walls, is where you either need a metal wiring method, or plenum-rated cable.

 

[mwm1752]

A good percentage of them are for venting and have no liquid in them.

j
Just methane gas :blink:

 

[ron]

The meaning of the word plenum is a little confusing.

To clarify, no wiring that is not directly necessary for the functionality of the air handling system is allowed in physically constructed ducts or plenums. Examples of such wiring are air temperature/speed sensor wiring or fan power/control wiring, that has no other option other than to be in the physically constructed duct/plenum. To contrast with physically constructed plenums, a plenum space, built with building walls and ceilings instead of duct walls, is where you either need a metal wiring method, or plenum-rated cable.

I think 300.22(B) & (C) makes it clear that PVC is not permitted in ducts and other spaces used for environmental air (plenums).

I was trying to see about inside walls, etc.

 

[GoldDigger]

I think 300.22(B) & (C) makes it clear that PVC is not permitted in ducts and other spaces used for environmental air (plenums).

I was trying to see about inside walls, etc.

I think that the determining characteristic would not be residential versus commercial, but rather the building construction type required for the specific building occupancy.

 

[ron]

I think that the determining characteristic would not be residential versus commercial, but rather the building construction type required for the specific building occupancy.

I know that exists for NM cable, but couldn't find that for PVC

 

[GoldDigger]

I don't think it is there.
There may be contract terms requiring a metallic raceway or cable though.

Sent from my XT1585 using Tapatalk

 

[JFletcher]

I dont see a reason why RPVC couldnt be used indoors. Ive run many a thousand of feet of ENT for comm cable, tho it's not permitted in an air handling space (300.22?).

 

[tom baker]

IMO PVC conduit inside, exposed (above a suspended ceiling) just looks sloppy, and too much like a DIY job. 3/4" PVC has to be supported every 3 feet, 1 foot from a box. EMT is faster to install, and not EGC is required.
Typically you'll see MC cable or a mix of MC and emt

 

[ron]

I don't think it is there.
There may be contract terms requiring a metallic raceway or cable though.

Sent from my XT1585 using Tapatalk

Luckily I write the Contract terms. ?

 

[kwired]

IMO PVC conduit inside, exposed (above a suspended ceiling) just looks sloppy, and too much like a DIY job. 3/4" PVC has to be supported every 3 feet, 1 foot from a box. EMT is faster to install, and not EGC is required.
Typically you'll see MC cable or a mix of MC and emt

3/4 PVC can be up to 3 feet from box to first support as a general rule, and every 3 feet afterward.