Heating PVC for bending purposes

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Carlos B

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Is heating PVC conduit allowed per code? I need to do some bends coming up into a concrete column that will have a cage in it. If I can heat and bend the 1" PVC I can install fairly easy and quick. I looked in the 2014 code book but did not find anything that said I could do it or not. Does anyone have any insight into this?

Many thanks
CB
 
352.24 {'14}
Field bends shall be made only with identified bending equipment.
 
K8MHZ said:
1) Define identified


2) Define bending

3) Define heating
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Identified (as applied to equipment). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.
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So I recognize that a heat gun, or my truck exhaust, or a gas grill or burning off half a can of glue, is suitable for the specific purpose of heating and bending PVC for my given application. :angel:
 
electrofelon said:
Have you ever tried that? It might actually work in a pinch....
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Newer trucks the emission control makes the exhaust gas pretty cool and it don't heat the pipe like it used to back in the eighties. In a pinch, pouring a can of glue in the ditch and lighting it on fire worked faster.... I mean, probably would work faster.
 
PVC Bender

PVC Bender

I use my Greenlee 851 or 849 to do most of it. Use to have a Greenlee 860-4 blanket heater but it didn't last long; handy in a ditch though. I have one foreman who insists on using the brush torch and he is good at it with very few scorch marks so it works well, and fast. I've looked at the Hotbend product and will probably buy one soon.
 
I use a propane torch with a fan nozzle. It works pretty good if you don't stop in one place too long. I'd love to have a heat box but no room on the truck. I only make bends for weird angles otherwise I just buy 90's and 45's. I rarely do any PVC work bigger than 2".
 
Anybody use compressed air or pack the conduit with sand to keep it from distorting or collapsing where you make the bend? I have a set of end plugs and a compressed air tank fitted with a low pressure regulator to put maybe 5psi in the conduit before heating in a hotbox. Only way to bend 1-1/2 on up.

-Hal
 
hbiss said:
Anybody use compressed air or pack the conduit with sand to keep it from distorting or collapsing where you make the bend? I have a set of end plugs and a compressed air tank fitted with a low pressure regulator to put maybe 5psi in the conduit before heating in a hotbox. Only way to bend 1-1/2 on up.

-Hal
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Waste of time.
None of the Journeyman or Master Electricians I apprenticed under would ever allow the time to do this.

Nor do I want mine wasting time doing this either.

If they want to experiment with perfect pvc bending on their own time they can, but not on mine.

Bending PVC is not rocket science.

All it takes is experience.

JAP>
 
353.24 Bends — How Made
Bends shall be so made that the conduit will not be damaged
and the internal diameter of the conduit will not be effectively
reduced.
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jap said:
If they want to experiment with perfect pvc bending on their own time they can, but not on mine.

Bending PVC is not rocket science.

All it takes is experience.
Click to expand...

So you are OK with egg shaped bends? It's guys like you who give PVC a bad name.

-Hal
 
hbiss said:
Anybody use compressed air or pack the conduit with sand to keep it from distorting or collapsing where you make the bend? I have a set of end plugs and a compressed air tank fitted with a low pressure regulator to put maybe 5psi in the conduit before heating in a hotbox. Only way to bend 1-1/2 on up.

-Hal
Click to expand...


May be a waste of time on smaller conduit, but if you are bending bigger ones it isn't a bad thing. Greenlee makes them with a relief valve. I can't tell if you are referring to those or some home made ones.Either way, there is no need to put compressed air in the pipe. I challenge you to try without it. The air inside heats up and expands more than enough to keep the pipe from collapsing and you still need the relief valve to let pressure off so the plug doesn't hurt someone.

As far as time waste, it wastes less time than working the bend for 5 minutes until the PVC cools enough to hold its shape.
 
Strathead said:
May be a waste of time on smaller conduit, but if you are bending bigger ones it isn't a bad thing. Greenlee makes them with a relief valve. I can't tell if you are referring to those or some home made ones.Either way, there is no need to put compressed air in the pipe. I challenge you to try without it. The air inside heats up and expands more than enough to keep the pipe from collapsing and you still need the relief valve to let pressure off so the plug doesn't hurt someone.

As far as time waste, it wastes less time than working the bend for 5 minutes until the PVC cools enough to hold its shape.
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We did exactly that on a 4" run back in the day. It worked great with no compressor, and kept the kinks out.
 
While we're on the subject, is there any code that limits the amount of tension in a conduit from bends? With smaller conduit, one can simply glue a joint that isnt perfectly aligned, bend the conduit while under tension then secure it with straps. With larger, it seems to me that any slight misalignment is usually taken care of by the small amount of slop in the joint, i.e., the joint is crooked

Also, anyone have a link to the plugs/plug kit one would use with compressed air?
 
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