Bending RNC with hand benders

Status
Not open for further replies.
K

KJay

Member
Location
MA
First of all, Happy New Year to everyone!

I see electricians using regular EMT/RMC/IMC hand benders for cold bending SCH 40 and SCH 80 PVC RNC because they have the proper bend radius.
Where can I find info that says these benders are specifically identified for use with RNC?
I haven’t been able to locate information on any bender manufactures website’s or on Carlon’s website mentioning this practice.
Seems like it could be a real time saver if it’s legitimate.

Thank you :confused:
 
Last edited:
mdshunk

mdshunk

Senior Member
Location
Right here.
I don't think there are RNC bending shoes. I use the hand bender for the smaller sizes, and might grab a shoe from an RMC rig to form a warm piece of the larger sizes in. Mostly, I just lay it on the floor and form it to some marks I made on the floor for an offset or whatever. You can't really screw up and go less than the min bending radius most of the time anyhow without kinking the pipe, so no worries there. Greenlee makes a protractor gizmo for holding warm PVC in place for bends, but I've never used it.

Where can I find info that says these benders are specifically identified for use with RNC?
Click to expand...
What's it matter, anyhow? The resultant bend radius is all that matters. You could bend it around a plumber's back side, as far as that goes.
 
mdshunk

mdshunk

Senior Member
Location
Right here.
nakulak said:
not to mention the fact that the radius might be way too big
Click to expand...
No violation there. Pick a bricklayer's back side for a smaller radius.

Seriously, though, I'm not real sure why the suitability of a certain tool should matter, and long as you don't go under the minimum bend radius. I'm not ashamed to admit that I did a rack of PVC offsets by forming them over a few 5 gallon buckets. It just so happened that they were close enough to the offset height that I needed, and it kept every pipe the same. I've seen guys pound nails or blocks of wood onto a sheet of plywood to make a jig to form multiple pieces of PVC on, so that they were all the same. Whatever it takes...
 
Last edited:
iwire

iwire

Moderator
Staff member
Location
Massachusetts
mdshunk said:
Seriously, though, I'm not real sure why the suitability of a certain tool should matter, and long as you don't go under the minimum bend radius.
Click to expand...

I agree and will admit I used many different things to bend RNC, EMT, IMC.

But with regard to RNC it seems the CMP felt the need to limit us...


352.24 ...... field bends shall be made with bending equipment identified for the purpose.....

Looks like we need to use a sharpie and write 'RNC Bender' on the plumbers rear side. :wink:
 
Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
There is an old saying "if the shoe fits..."
Okay, that may be for something else, but I think you can get the idea.

I think it is pretty cool that smaller size PVC can be bent by hand benders without the aid of heat.

If one cannot use "other means" to perform some of the work we do in this industry, there goes ingenuity.
 
480sparky

480sparky

Senior Member
Location
Iowegia
KJay said:
Where can I find info that says these benders are specifically identified for use with RNC?
I haven?t been able to locate information on any bender manufactures website?s or on Carlon?s website mentioning this practice.
Click to expand...

Pipe Viper
 
K

KJay

Member
Location
MA
iwire,
You hit on my concern exactly. NEC 352.24, "field bends shall be made with equipment identified for the purpose"

I know about those bending springs for cold bending RNC, but could never find any written confirmation of suitability of standard conduit benders being ?identified? or designed for cold bending PVC without any additional tools.
I wouldn?t have a problem doing this on my jobs if I could point to something in writing that says it is a legitimate technique.
If it is not an ?identified? method, I don?t want to follow along and do it just because somebody else does.

This topic began with a discussion with someone that an industrial heat gun is not ?identified for the purpose?, for bending small diameter RNC, but it seems that it would be more appropriate and consistent with normal RNC heat bending practices. :confused:
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
KJay said:
You hit on my concern exactly. NEC 352.24, "field bends shall be made with equipment identified for the purpose"
Click to expand...

Yes, but I think it is a poorly written piece of that code section.

This topic began with a discussion with someone that an industrial heat gun is not “identified for the purpose”,
Click to expand...

Does that section actually require the heat gun be identified for the purpose of bending?

That section talks of bending the pipe, but heat guns do not bend pipe, people bend pipe, heat guns heat the pipe and that section says noting about heating.


Charlie's rules come into play here......
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I tried cold bending a piece of 1/2" with an EMT bender after reading about it here. IMO it wasn't worth the effort unless it was getting buried underground. The radius was awful looking.
 
K

KJay

Member
Location
MA
Just to reconfirm my suspicions, I also tried bending a piece of 1/2? Carlon Sch 40 RNC on the concrete floor of my basement with an Ideal bender at an ambient temperature of 68 degrees F. First attempt was to bend a 90 on the floor. I bent the RNC almost 180 degrees and held it there for several seconds to allow for flex back. Still did not set anywhere even close to 90 degrees, not even on the second attempt. There was a choppy rippling and obvious discoloring from stressing the plastic though.
Then I tried bending a 90 with the foot of the bender in the air. Forget that. Also, watch out for your teeth.
I remember fooling around as an apprentice trying to bend Sch 40 PVC conduit like this about 25 years ago, but I never thought I would see guys doing this on a jobsite.
Maybe if you used those steel bending springs or else live in a warm climate this method would suffice, but as far as I am concerned, without first applying heat the RNC conduit, this method doesn?t seem very professional.
 
480sparky

480sparky

Senior Member
Location
Iowegia
I once worked on several agricultural buildings in the middle of August. We didn't have a hot box (in the sense of one made by Greenlee), but the Porta-Potty got plenty warm, so we stuck our PVCs in there to heat them up.

Worked pretty good!:smile:
 
chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
KJay, did you try to bend the 90 in one motion then hold it? Try "working" the conduit. Keep the bender moving back and forth a little at first working towards the desired radius. Takes a few minuites and you will have to over-bend it.
 
K

KJay

Member
Location
MA
Hi Chris,
Yes, I tried it several different times in different ways. Both with one shot and multiple shot.
I just can't see this as a viable installation method. At least not for me anyway.
I think that if someone developed a Chicago style quick-heating bender for RMC, they would retire young and wealthy. :wink:
 
Status
Not open for further replies.
Top