red devil...?

Merry Christmas
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chris kennedy said:
Man I can't find the link (questionable computer skills) but heres a quote from NEMA Executive Staff

"The confusion stems from the fact that some MC cable manufictures include anti-short bushings with their cable. The inclusion of anti-short bushings with coils or reels of MC cable is based on historical practice relating to the requirements of 320.40."

320 is AC not MC
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NEMA Engineering Bulletin 90
 
Anti-short with MC Cable?

Anti-short with MC Cable?

kpepin said:
I think it's been asked before but...

If they are not required, why do they come with MC? It must cost the manufacturer of the cable just a little more to include them. Why do they even bother attaching them to the cable?
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It's about the safety, not just about the requirement. Maybe they should be required? Having them included automatically, makes it more convenient for the contractor who does use them.

Because they are a UL/CSA approved product costing pennies, why wouldn't you use them as an added layer of protection?

With all the different methods of terminating the armor and the length of the horizontal cut, the length of the anti-short bushing protects the inside of the sharp armor from causing a short.
 
peter d said:
Well, if this was such an issue why doesn't the NEC require them like AC cable?

I still don't totally buy your argument, because with MC connectors and the MC clamps in old and new work boxes, the conductors must still pass unprotected over a metal surface (the throat of the connector or the clamp.) The redhead offers no protection for that. And I know we've all see how close the conductors get to the edge of some MC connectors. I think the conductors are more vulnerable to shorting at those points than at the armor/conductor point, especially when the connectors get overtightened.
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So do you feel that the anti-short is necessary for MC Cable or not?
 
red devil

red devil

I do ot understand what the confusion is about these "little red thingees". I have allways used them. I install them as the manufacturer suggests, tighten the clamp down all the way and I never have had a short.
 
Charleds Burton said:
I do ot understand what the confusion is about these "little red thingees". I have allways used them. I install them as the manufacturer suggests, tighten the clamp down all the way and I never have had a short.
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Yep !

It really is just that simple. . I find it unbelievable that some people are against them.

David
 
iwire said:
Once you are responsible for the time it takes to repair an MC that shorted in a recessed box without a redhead that may not have shorted with red head I think your tune will change.

Redheads are almost always free and take almost no time to install.
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Charleds Burton said:
MC connecters are designsd so that the wire is allready protected going through the throat or at least the ones I use are. They have a rolled edge which protects the conductors.
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peter d said:
I still don't totally buy your argument, because with MC connectors and the MC clamps in old and new work boxes, the conductors must still pass unprotected over a metal surface (the throat of the connector or the clamp.) The redhead offers no protection for that. And I know we've all see how close the conductors get to the edge of some MC connectors. I think the conductors are more vulnerable to shorting at those points than at the armor/conductor point, especially when the connectors get overtightened.
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?the edge of some MC connectors. I think the conductors are more vulnerable to shorting at those points?
How is it vulnerable to a machined rolled edge ?
You don?t see a problem with a newly cut jagged edge but you see one with a smooth rounded edge, why is that ?

David
 
The fact is that any plastic insulation on the connector doesn't slide in between the cut jacket and the conductor insulation. . The need for the antishort can be debated but the plastic on the connector does not prevent the jacket from driving into the insulation when the connector squeezes.

The CMP obviously doesn't care about cut steel being compressed into conductor insulation but just because they come to that conclusion doesn't mean they're right. . It only means that it's code.

I enforce the code, even when a CMP doesn't get it right.

David
 
Wow you guys have really run with this. I got my answer and hadn't checked back for a few days.

The original question was sparked by a customer of ours (we manufacture cable) who was getting pestered by an inspector who wanted red devils installed on our MC cable. The customer wanted to know if they were required since they had already installed the cable without them. I sent them that pdf document and haven't heard anything back.

After reading this thread, it certainly seems that it is better to just go ahead and install them whether they are required or not. Better safe than sorry.
 
Never use them on MC and never will unless it becomes a requirement.

People can say what they want about the edges and anything else. The cable was tested and found to be safe without them therefore I do not use them and sit in waiting for the poor old uneducated inspector to come along and write up them not being used.
 
Next thing ya know, they'll have anti-short "red devilheads" for Wiremold 500 and 700. They'll come in a little burlap sack taped to a length of WM ......:)
 
you are right T&B still says to use anti short bushing even with insulated throat fittings. they make bushings for wire mold you have to purchase them separate and I do not believe they were plastic....
 
cschmid said:
you are right T&B still says to use anti short bushing even with insulated throat fittings. they make bushings for wire mold you have to purchase them separate and I do not believe they were plastic....
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They are metal and they don't work very well IMO.
 
jwelectric said:
Never use them on MC and never will unless it becomes a requirement.

People can say what they want about the edges and anything else. The cable was tested and found to be safe without them therefore I do not use them and sit in waiting for the poor old uneducated inspector to come along and write up them not being used.
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"The cable was tested and found to be safe without them"
I'll bet you believe everything the manufacturers and CMP members say about AFCIs too !

Go ahead, crank down on that connector and squeeze that jacket cut edge down into the insulation. . Have a blast ! . Do you think it bothers the people with common sense ?

You have your CMP blessing. . You don't need anything else.

David
 
dnem said:
"The cable was tested and found to be safe without them"
I'll bet you believe everything the manufacturers and CMP members say about AFCIs too !

Go ahead, crank down on that connector and squeeze that jacket cut edge down into the insulation. . Have a blast ! . Do you think it bothers the people with common sense ?

You have your CMP blessing. . You don't need anything else.

David
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Bravo! David. :)
 
antishortbushing said:
So do you feel that the anti-short is necessary for MC Cable or not?
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Since they are not required by the NEC, it's up to the person doing the actual installation or the boss who makes the rules for his employees. When I worked for a large company, it was field policy to always use anti-short bushings. So I used them. When I do my own work, I don't use them.

And until the time comes when a short happens from not using an red head, I'm not going to start using them. That is strictly my choice and I maintain that when care is taken to strip the armor and apply the proper connector, anti-short bushings are not necessary.

Of course, if I had employees I would change my mind and require them, because I can't control what they would do.

To quote from Iwire, the great thing about our trade is we get to do things the way we want to. And if we don't like being told what to do, we can start our own companies and do it "our way." :)
 
So when you clamp down that connector over the top of the metal jacket and squeeze the cut edge into the conductor insulation, anything that might protect the insulation from that jagged edge is ?useless? ?
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This is 2007. I don't use "clamp" style connectors. Generally, snap ins are the logical choice. I DO slip the connectors on BEFORE stripping away the plastic surrounding the wires though so they have that extra protection.

And....if you are clamping the connectors tight enough to short the wiring....you are claming them WAY too tight. Be gentle my friend.
 
Mike Whitt,

My post #53 was a good old fashioned "shot over the bow". . I fully expected you to "come about" and let loose with every canon on board.

But all I've heard to date was an "ARGH ! [grumble, grumble] ..... implying ..... [grumble, grumble] ..... blessing ..... [grumble, grumble] ARGH !" and you set sail in the other direction. . A ship flying the black flag with the white pitbull skull and cross bones is expected to be a little more feisty.

David
 
For me it boils down to this. I use them. It's my installation we're talking about. I don't care if someone else doesn't use them. I learned to use them with BX, kept using them with AC, and see no reason not to use them with MC. Especially when I get a new handful with the MC I buy. And it's not the only thing I do that's "not required."
 
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