Romex nm J-box clamps

[alan camby]

Today I was running some Romex to lengthen a 3-way switch run. All the cable is behind drywall and I assumed that there was at least one or two staples somewhere behind the studs. Running all new cable would have been a major pain. So I installed a 4-11/16 junction box to the old cable and came out with the new yellow nm Romex cable. This new style...well been out for probably 20+ years, has a really thin yellow cable jacket.

So I clamped the cable with the common romex j-box clamps. Turned power on after installing the new switch further down the wall. Pop goes the breaker. Now I just snugged these clamps but they cut right through the cable and power shorted to ground. Pulled to a new spot in cable. Took some of the old thick style Romex cable jacket off the old romex and used it as a added protection layer. Careful just snugged down the clamps and all is good now.

So do they make a thin protection kind of wrap for Romex to install where it is clamped? I can't find anything with Google. These clamps come from India or some place like that and are full of sharp edges. I got mine at lowes, and yes they were for the nm style wire as I know there is a slightly different style for mc style metal clad cable. Just seem like these clamps are hard on the cables. Oh and sometimes I need to run more than one cable through a clamp so really want to avoid the cord grip style with the rubber insert that smashes around a cable( the style that is usually used with SO cable)

Thanks for any advice.

Attached is the style I used but they were for the 1/2" knockouts.

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[gagecalman]

A different option.
https://www.lowes.com/pd/Sigma-Electric-ProConnex-3-8-in-Snap-in-Connector-Conduit-Fitting/3151125

 

[Terry D]

You either had a clamp that was faulty some how, I mean with something sharp inside of it. Or the clamp was tightened way to tight. The plastic connectors are the way to go these days

 

[yatg]

The plastic connectors totally **** if you ever need to pull a cable out of the box.

 

[Raisedonadeere]

The plastic connectors totally **** if you ever need to pull a cable out of the box.

Amen, you have to be especially careful to not allow cable to be pulled further than you want. It is very difficult to avoid having this happen when pushing cable into the box. I have learned to have the cable stapled down such that what ever gets pushed into the box can stay.

If the cable is not anchored properly outside the box it is easy to pull any slack cable into the box while attaching the device and then you wind up with too much cable in the box and as said, very difficult to remedy. But it is mostly just a relearning thing and I used bunches of them in my new garage build. Much faster and avoids what the OP posted about.

 

[Innovate1]

I would take a close look at the clamp you had trouble with. There may be some somewhat sharp edges on the cast part where the cable goes through but the stamped piece is formed so the contact is in the middle so I don't see any way you could get a short unless something was wrong or you put a LOT of tension on the cable to push it against the cast corner. Even then it seems unlikely. Maybe the romex insulation was thin and marginal to start with? Definitely shouldn't happen and you shouldn't need to sleeve the romex where it goes through.

 

[theoldwizard1]

The plastic connectors totally **** if you ever need to pull a cable out of the box.

Yep, but they are designed to only used ONCE !

 

[Terry D]

The plastic connectors totally **** if you ever need to pull a cable out of the box.

I use the Dottie brand. If you stick a small screwdriver in it, it will push the tab away and the wire comes right out. If you are referring to the button type ones, I agree, I throw those things in the trash