Type MC cable I am being told - Electrician Talk - Professional Electrical Contractors Forum

mdny · 05-11-2012, 02:29 PM

Type MC an MC lite I'm being told doesn't need a anti short bushing (red head) if this is true tell me where it states it in the NEC. If its required please direct me towards it. I never heard of such a thing but I'm being told through conversation with an electrical inspector it's not required with this type of cable. Any feedback will be a great help. Thanks

Gamit · 05-11-2012, 02:32 PM

Quote:

Originally Posted by mdny

Type MC an MC lite I'm being told doesn't need a anti short bushing (red head) if this is true tell me where it states it in the NEC. If its required please direct me towards it. I never heard of such a thing but I'm being told through conversation with an electrical inspector it's not required with this type of cable. Any feedback will be a great help. Thanks

I believe this is true and have been told this multiple times but use them regardless

wildleg · 05-11-2012, 02:33 PM

it's true. bushing is needed with AC cable, but not MC. do a search here or on MH and you'll find the reference, I think it's the listing of the cable but I forget. (we use them regardless too - I think it's best practice)

220/221 · 05-11-2012, 02:34 PM

Quote:

Originally Posted by mdny

Type MC an MC lite I'm being told doesn't need a anti short bushing (red head) if this is true tell me where it states it in the NEC. If its required please direct me towards it. I never heard of such a thing but I'm being told through conversation with an electrical inspector it's not required with this type of cable. Any feedback will be a great help. Thanks

It's not going to be an NEC issue. Refer to the maufacturers installation instructions and you will find your answer (not required).

HARRY304E · 05-11-2012, 02:52 PM

Quote:

Originally Posted by mdny

Type MC an MC lite I'm being told doesn't need a anti short bushing (red head) if this is true tell me where it states it in the NEC. If its required please direct me towards it. I never heard of such a thing but I'm being told through conversation with an electrical inspector it's not required with this type of cable. Any feedback will be a great help. Thanks

Read 320. 40 for type AC CABLE.."BX"

Them read 330.40 type Mc cable...not required.

cortez · 05-11-2012, 02:53 PM

Here an anti-short bushing is always a required item in current installations.

Chicago code also requires a grounding wire (bare) for any BX or equivalent. The bare wire can be wrapped around the BX end ,securing the anti short bushing by wrapping it around it and then secured by the screw in the BX connector.

Shockdoc · 05-11-2012, 04:02 PM

But they give you a small care package of red heads with every roll, enough to wire up about 7 feed thru boxes.

Celtic · 05-11-2012, 09:38 PM

Quote:

Originally Posted by mdny

Type MC an MC lite I'm being told doesn't need a anti short bushing (red head) if this is true tell me where it states it in the NEC.
If its required please direct me towards it. I never heard of such a thing but I'm being told through conversation with an electrical inspector it's not required with this type of cable. Any feedback will be a great help. Thanks

The requirement for Type AC cable is 320.40
This requirement is absent in 330.40

This difference can also be seen in NEMA Bulletin 90:

Use of Anti-Short Bushings for Terminating Type MC Cable

While use of an anti-short is NOT a requirement, however it is good practice to install one.

**frenchelectrican** · 05-11-2012, 11:57 PM

Quote:

Originally Posted by Shockdoc

But they give you a small care package of red heads with every roll, enough to wire up about 7 feed thru boxes.

If you do alot of HR's you will end up have extra on hand and the other hand from time to time I get a box full of antishorting bushing as well.

Right now one of my tool box which I store the antishorting bushing it kinda overflow at the moment

Merci,
Marc

HARRY304E · 05-12-2012, 12:02 AM

Quote:

Originally Posted by frenchelectrican

If you do alot of HR's you will end up have extra on hand and the other hand from time to time I get a box full of antishorting bushing as well.

Right now one of my tool box which I store the antishorting bushing it kinda overflow at the moment

Merci,
Marc

You should open a Anti-short bushing store you will be rich..

macmikeman · 05-12-2012, 12:05 AM

Truth is it took years before most inspectors learned that they are not required for mc cable. I used to tell em that and they treated me like I was crazy, even though I was spot on right about it. Now that I think about it , its just like how you guys treat me too...................

**frenchelectrican** · 05-12-2012, 12:06 AM

Quote:

Originally Posted by HARRY304E

You should open a Anti-short bushing store you will be rich..

Kinda but BTW the Americian MC cable and European MC cable are the same size but slightly differnt rating plus metric conductor that it but both look the same.

Merci,
Marc

HARRY304E · 05-12-2012, 12:09 AM

Quote:

Originally Posted by macmikeman

Truth is it took years before most inspectors learned that they are not required for mc cable. I used to tell em that and they treated me like I was crazy, even though I was spot on right about it. Now that I think about it , its just like how you guys treat me too...................

OH!

We never do that here....

...................

. ....

....

chicken steve · 05-12-2012, 07:30 AM

heaven forfend Mac....~CS~

kennydmeek · 05-12-2012, 07:34 AM

I think I'd lay awake the rest of my life if I installed something without one...

BBQ · 05-12-2012, 07:40 AM

Quote:

Originally Posted by kennydmeek

I think I'd lay awake the rest of my life if I installed something without one...

98% of the time I use them, if I don't have one handy I may leave it out and sleep fine.

Here is the NEMA bulletin about it.

http://www.nema.org/stds/eng-bulleti...ulletin-90.pdf

Quote:

BULLETIN
No. 90
August 14, 2002
Use of Anti-Short Bushings for Terminating Type MC Cable

There has been much confusion within the Installation and Inspection communities regarding the
use of anti-short bushings for terminating Type MC cable. The confusion stems from the fact
that some MC cable manufacturers 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 of the NEC, which mandates the use of anti-short bushing or its
equivalent protection for Type AC Cable

Fittings used with Type MC Cable are required to be listed per 330.40 of the NEC. NEMA
supports the use of listed fittings for MC Cable. The design of these fittings may or may not
include an insulated throat however, they are required to be provided with a smooth, rounded end
stop so that the metal sheath of the cable will not pass through and the wires will not be damaged
in passing over the end stop. Whether or not an insulated throat is part of the listed product, these
listed MC fittings do not require an additional anti-short bushing. Anti-short bushings that may
be supplied by MC Cable manufacturers are for optional use by the installer, however they are
not required.

ROP #7-116 from the May 2001 Report on Proposals (ROP) for the 2002 NEC was a proposal
seeking to require anti-short bushings on all MC Cable termination installations.
The following is an excerpt from the Panel statement rejecting the proposal:

Anti-short bushings are not required for Type MC cable in accordance with the listing for
the product. The termination fittings approved for use with Type MC cables are designed
such that the wires will not come in contact with the cut edge of the armor; the throat of
the fitting is small enough to prevent contact with the armor. Type MC termination
fittings perform the same function for Type MC cable as Type AC terminations plus the
anti-short bushing do for Type AC cable.

NEMA supports the uniform adoption and enforcement of the NEC and recommends that local
Authorities Having Jurisdiction follow the requirements of NEC Section 330.40, Boxes and
Fittings for MC Cable. Section 330.40 requires that the fitting be listed, but does not mandate the
use of an anti-short bushing.

Distribution List:
Standards and Conformity Assessment Policy Committee
Codes and Standards Committee
NEMA Executive Staff

**Speedy Petey** · 05-12-2012, 07:46 AM

Quote:

Originally Posted by cortez

Here an anti-short bushing is always a required item in current installations.

Chicago code also requires a grounding wire (bare) for any BX or equivalent. The bare wire can be wrapped around the BX end ,securing the anti short bushing by wrapping it around it and then secured by the screw in the BX connector.

Are you talking about the bond strip inside AC cable? This is NOT a ground.

wildleg · 05-12-2012, 09:11 AM

Quote:

Originally Posted by cortez

Here an anti-short bushing is always a required item in current installations.

Chicago code also requires a grounding wire (bare) for any BX or equivalent. The bare wire can be wrapped around the BX end ,securing the anti short bushing by wrapping it around it and then secured by the screw in the BX connector.

where is that in the Chicago code ?

user4818 · 05-12-2012, 10:07 AM

Quote:

Originally Posted by Speedy Petey

Are you talking about the bond strip inside AC cable? This is NOT a ground.

And it can be cut off. I don't do the backwrap trick with AC cable, not that I encounter it often.

BBQ · 05-12-2012, 10:08 AM

Quote:

Originally Posted by Peter D

And it can be cut off. I don't do the backwrap trick with AC cable, not that I encounter it often.