# Cutting flexible conduit



## MDShunk

How do you cut flexible raceways? Hacksaw? RotoSplit? Dikes? 

NEMA standards publication FB2.20-2003, _"Selection and Installation Guidelines for Fittings for use with Flexible Electrical Conduit and Cable"_ covers the the cutting of flexible raceways. You can download it here for free, if you're interested in reading it: http://www.nema.org/stds/fb2-20.cfm#download

The section that related to cutting reads as follows:

*2.4.1 Cutting Conduit*
_Specialized tools are available and widely used to cut sections of Flexible Metal Conduit. These tools are efficient and effective in safely cutting through the convolutions. Unfortunately, their use always results in a sharp angle cut on the end of the conduit and often cuts partially through the next remaining full convolution. Regardless of whether one of these specialized tools is used, the most effective fitting assembly is ensured when the end of the conduit is squared by carefully cutting off the angled edge and any damaged convolutions using a pair of diagonal pliers, a hack saw, or the like. If this important step is not taken, complete seating of the conduit into the fitting, a smooth non-abrasive wire entry, and a secure bearing surface for the securement screw or clamp cannot be assured (see Figure 2-5)._

It seems that the very end of flexible conduits is to be very square. The figure 2-5 that they mention is this picture below. The "incorrect" image seems to show exactly what you get when you use a RotoSplit type tool:









Image courtest of the National Electrical Manufactuers Association (NEMA)


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## brian john

Sears Craftsman Straight Cut Avaition Snips. (tin snips)


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## MDShunk

There are a few tools that are designed purposely for square cuts on flexible raceways. One is pretty new, and is Seatek's "Swing-Saw". (US$41.95) The other is pretty old, and is Jack Benfield's original "Benfield Sawbox". (US$57.50). Below are some pics of my Benfield Sawbox:


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## brian john

Marc While I feel standards are good and in many cases necessary, do you feel improperly cut Greenfield (not liquidtite) is an issue, I know of issues with improperly cut BX and MC but Greenfield?


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## MDShunk

brian john said:


> Marc While I feel standards are good and in many cases necessary, do you feel improperly cut Greenfield (not liquidtite) is an issue, ...?


With certain brands, models, and styles of fittings (particularly, 90°) I believe that a good square cut is important. With some models, it matters less. 

Mostly, I post about standards I run across that are different than what most people do (including myself, many times), in hopes that some interesting discussion will result. The quality of the resulting discussion is more important to me, most times, than the actual topic that began it. :rockon:


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## NC_Electrician

I use a Roto-Split but I always square off the edge as much as possible and use 2 reds to insulate and protect the conductors.


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## MDShunk

NC_Electrician said:


> I use a Roto-Split but I always square off the edge as much as possible...


That seems to work, too, to comply with the standard.



NC_Electrician said:


> ...and use 2 reds to insulate and protect the conductors.


 I use two redheads also when I don't have one big enough. Alternate the splits. Sometimes, I'll use two just because they're stuck together, and I just don't bother getting them apart.


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## NC_Electrician

I put them 180 degrees apart, so the seams aren't touching each other. I just feel that provides the most possible protection to the conductors that is possible with that wiring method and material.


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## MDShunk

NC_Electrician said:


> I put them 180 degrees apart, so the seams aren't touching each other. I just feel that provides the most possible protection to the conductors that is possible with that wiring method and material.


That's cool. I often end up with surplus red-heads anyhow, so that would be a good way to use them, perhaps. I think NEMA recommends that the manufacturer's supply at least 35 suitably sized anti-short bushings with each roll of type AC cable, so most of them ship at least this many with type MC cable also (even though you don't need them with MC).


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## TOOL_5150

MDShunk said:


> That's cool. I often end up with surplus red-heads anyhow, so that would be a good way to use them, perhaps. I think NEMA recommends that the manufacturer's supply at least 35 suitably sized anti-short bushings with each roll of type AC cable, so most of them ship at least this many with type MC cable also (even though you don't need them with MC).


Yeah I always thought 35 or sometimes on MC 25 is weird. You technically would always have 1 left over. Why not an even number? Arent you going to land both sides of the cable every time?

~Matt


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## 220/221

Al flex....snap it and stick my wire strippers into the end, cutting it with the cutting part.. Use screw in connector so squareness isn't an issue.

Metalic Sealtite....ring it with a razor knife and snap/cut just like AL flex.

MC....snap and cut carefully with dikes.

Haven't used a hacksaw in ages.


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## randomkiller

Thats what Klein makes this for. http://store.comosuperstore.com/092644760143.html


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## 220/221

Thanks but my bags aready weigh 90 pounds.

I like multi purpose tools.


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## randomkiller

220/221 said:


> Thanks but my bags aready weigh 90 pounds.
> 
> I like multi purpose tools.


WHAT, you carry your own bags? No apprentice?


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## 220/221

He will carry them to and from the truck but when I'm working I'm not about to be reaching into his pouch.....besides, I make him stay back at least 6' at all times.


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## Control Freak

MDShunk said:


> That's cool. I often end up with surplus red-heads anyhow, so that would be a good way to use them, perhaps. I think NEMA recommends that the manufacturer's supply at least 35 suitably sized anti-short bushings with each roll of type AC cable, so most of them ship at least this many with type MC cable also (even though you don't need them with MC).


What is the reason for not using redheads with MC type cable? is it because of the plastic inside the armor as opposed to the paper in the BX


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## JohnJ0906

Control Freak said:


> What is the reason for not using redheads with MC type cable? is it because of the plastic inside the armor as opposed to the paper in the BX


Not required.

I have a copy of the NEMA bulletin confirming this, but it seems it will take longer than I thought to find it.


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## JohnJ0906

Here we go - http://www.snapdrive.net/files/507790/Bulletin-90.pdf


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## RUSSIAN

The first time you have a 277 lighting circuit blow up in your face because the previous guy did not use an anti-short will make think twice about using them


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## JohnJ0906

RUSSIAN said:


> The first time you have a 277 lighting circuit blow up in your face because the previous guy did not use an anti-short will make think twice about using them


I do use them.

There is no *requirement *in the NEC to use them.


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