MC cable and duplex connectors - Electrician Talk - Professional Electrical Contractors Forum

Rikki · 03-22-2007, 09:54 PM

I know that you supposedly don't have to use red heads with MC connectors, because they're supposed to be self-bushed. Do you need to use red heads when you're using a duplex MC connector? They don't seem like they have any way to bush each MC, and you might legitimately need to use a red head. I know some people are going to say -always use a red head- but I'm trying to figure out the real answer and not what a person might do.

Thanks.

MDShunk · 03-22-2007, 10:19 PM

Always use a red head! (sorry, couldn't resist)

I don't know, but I see where you're coming from. Sounds like a question for NEMA, since that bulletin about not requiring anti-short bushings originally came from them. I have no idea how you ask NEMA a question, though.

Joe Momma · 03-23-2007, 04:31 AM

I've always known "red-heads" as a concrete anchor, but for MC I assume you mean "a$$holes", or as some fruity guy called them, "rose-buds".

I've only used anti-shorts with the type of MC connector that has a set-screw. The push in type; double or single barrel, I don't use them and have yet to see a problem.
Though I will point out that a quality installation depends on the installer.

raider1 · 03-23-2007, 10:16 AM

Quote:

I know that you supposedly don't have to use red heads with MC connectors, because they're supposed to be self-bushed.

The reason that you don't need to use anti-short bushings on MC cable is that the listed connectors for use with MC cable come with bushings in the connector themselves.

I still always use the anti-short bushings on my MC cable. (a little extra protection goes a long ways.

)

Chris

ssandoval · 07-08-2009, 04:15 PM

So am I correct in understanding that the NEC does not require anti-shorts for MC? I know ART 320.40 is very specific about requiring them for AC cable, but isn't all MC cable inherently AC. What's difference between AC, MC and BX? Someone, please?

raider1 · 07-08-2009, 04:49 PM

Quote:

but isn't all MC cable inherently AC.

No, the sheath of standard MC cable is not listed as EGC and the cable contains an insulated EGC.

AC cable has a small aluminum bond wire run in direct contact with the interior of the cable sheath that will help the sheath provide a low impedance fault current path without an additional insulated EGC.

Also "BX" is a trade term for AC cable similar to the term "Romex" for NM cable.

Chris

electricalperson · 07-08-2009, 05:01 PM

a lot of guys use romex connectors for MC. i hate doing that makes me feel like peter d

Black4Truck · 07-08-2009, 05:07 PM

Quote:

Originally Posted by electricalperson

a lot of guys use romex connectors for MC. i hate doing that makes me feel like peter d

Peter D uses connectors??

raider1 · 07-08-2009, 05:20 PM

Quote:

Originally Posted by electricalperson

a lot of guys use romex connectors for MC. i hate doing that makes me feel like peter d

If the romex connector is not listed for MC cable that could be a big problem. The sheath of the MC cable must still be bonded and you need to use a connector that is listed for MC cable.

Chris

electricalperson · 07-08-2009, 05:23 PM

Quote:

Originally Posted by raider1

If the romex connector is not listed for MC cable that could be a big problem. The sheath of the MC cable must still be bonded and you need to use a connector that is listed for MC cable.

Chris

only difference i see between an arlington MC connector and an arlington 3/8 romex connector is the bottom that sits inside the panel. the MC connector keeps all the wire in the center and a romex connector doesnt. i never looked up the UL listing of that stuff. i use MC connectors anyway

manchestersparky · 07-08-2009, 06:37 PM

AC generally has the conductors wrapped in paper and MC generally has the conductors wrapped in plastic.

Black4Truck · 07-08-2009, 08:34 PM

I think this is nit-picking.. put the

thing on.. the time it takes to accomplish this is seconds.

Even a HO could do this and the red heads are free

jsb · 07-08-2009, 09:34 PM

is anyone out there using mcap?

LJSMITH1 · 07-09-2009, 10:59 AM

Perhaps this will help explain where anti-shorts are to be used and why. MC is not the same as AC - even though it looks similar.

As for Southwire's MCap, what exactly are you looking for as far as info?

LJSMITH1 · 07-09-2009, 11:01 AM

Quote:

Originally Posted by raider1

If the romex connector is not listed for MC cable that could be a big problem. The sheath of the MC cable must still be bonded and you need to use a connector that is listed for MC cable.

Chris

Its a bit more than just a bonding requirement. There is also a cable stop requirement for AC/MC fittings. There is no similar requirement for NM.

Bottom line is always use fittings listed for the particular type and size cable/conduit you are using. The label on the box should tell you just about everything.

jsb · 07-09-2009, 11:02 AM

I have all the info I need I was just curious what parts of the country were using it

LJSMITH1 · 07-09-2009, 11:05 AM

Typically any area where MC/AC cable is widely accepted (i.e. NOT Chicagoland). It certainly does reduce the time to wire a job.

Be sure to use fittings listed for use with that cable.

zappy · 07-12-2009, 12:28 PM

Quote:

Originally Posted by Joe Momma

I've always known "red-heads" as a concrete anchor, but for MC I assume you mean "a$$holes", or as some fruity guy called them, "rose-buds".

I've only used anti-shorts with the type of MC connector that has a set-screw. The push in type; double or single barrel, I don't use them and have yet to see a problem.
Though I will point out that a quality installation depends on the installer.

And I always thought a a%#hole was a plastic bushing.

Termination · 07-19-2009, 12:15 PM

The union guy has never had a problem, Because they don't call you to repair your problems,

JohnJ0906 · 07-19-2009, 02:43 PM

Quote:

Originally Posted by zappy

And I always thought a a%#hole was a plastic bushing.

No, that's usually my helper.