MC Connectors & Anti Shorts

[Little Bill]

We have an inspector here that first says anti-shorts are needed for MC because they come with the roll. I say no unless the mfg says to use them as they are not required per the NEC.

Biggest problem or disagreement with the inspector is he says on the MC connectors that have the red sleeves in them still have to have the anti-shorts. I don't understand why a mfg would put the sleeves in a connector if they still required the anti-shorts. I believe the red sleeve is meant to do the same thing as the anti-shorts.

Am I wrong?

This is the type connector I am talking about.

 

[peter d]

They are not required for MC cable, so no, you are not wrong.

 

[peter d]

FWIW MC connectors are not required to have any kind of bushing either, it's just manufacturer option to make them that way.

 

[infinity]

I agree with Peter and since when does "comes with the roll" make it a code requirement?

 

[iwire]

Print the bulletin in this link and hand it to the inspector.

http://www.bptfittings.com/Public/D...- Use of Anti-Short Bushings for MC Cable.pdf

 

[Coppersmith]

We have an inspector here that first says anti-shorts are needed for MC because they come with the roll. I say no unless the mfg says to use them as they are not required per the NEC.

:lol::lol::lol: They come with the roll because inspectors keep saying they are required. Catch 22!

 

[iwire]

I know you are joking around but here is what NEMA says s the reason red heads ship with MC.

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

 

[jumper]

Many insulated throat connectors like the one shown are dual rated for AC and MC.

AC needs the anti short part, but MC does not.


Inspector needs to look at the difference between 320.40 and 330.40. Big difference.

320.40 Boxes and Fittings.
At all points where the armor of AC cable terminates, a fitting shall be provided to protect
wires from abrasion, unless the design of the outlet boxes
or fittings is such as to afford equivalent protection, and, in
addition, an insulating bushing or its equivalent protection
shall be provided between the conductors and the armor.
The connector or clamp by which the Type AC cable is
fastened to boxes or cabinets shall be of such design that
the insulating bushing or its equivalent will be visible for
inspection. Where change is made from Type AC cable to
other cable or raceway wiring methods, a box, fitting, or
conduit body shall be installed at junction points as re-
quired in 300.15.


330.40 Boxes and Fittings.
Fittings used for connecting Type MC cable to boxes, cabinets,
or other equipment shall be listed and identified for such use.

 

[macmikeman]

I agree the inspector is wrong. FWIW, once while using my impact drill to tighten the two screw type of connector to some mc I must have triggered too long. Turned on breaker and it popped right off, tracked it down and - overtightened connector. After that I short burst the gun, and hand tighten with a slot head screwdriver till snug only.

 

[Little Bill]

Print the bulletin in this link and hand it to the inspector.

http://www.bptfittings.com/Public/D...- Use of Anti-Short Bushings for MC Cable.pdf

Thanks!
Noted, Printed, & saved on phone!

 

[cloudibew]

NEMA says

NEMA says

Yep NEMA says nope, just depends how ticked off you want the inspector. Some battles just arent worth it. Fight him on this point and he may pick yer job apart over every little thing for the rest of the project and any future projects where he sees you. Sometimes its just better to accomodate them as they can get pretty petty over stoopit stuff.

 

[Coppersmith]

Yep NEMA says nope, just depends how ticked off you want the inspector. Some battles just arent worth it. Fight him on this point and he may pick yer job apart over every little thing for the rest of the project and any future projects where he sees you. Sometimes its just better to accomodate them as they can get pretty petty over stoopit stuff.

Yes. This is exactly why I always use them even though I know they are not required. To quote a famous leader "Sad!".

 

[infinity]

This is from the 2008 but the requirement is still the same:

7-34 Log #437 NEC-P07 Final Action: Reject
(330.40)
____________________________________________________________
Submitter: Joseph Lopez, Ludvik Electric
Recommendation: Revise text to read as follows:
Fittings used for connecting type M.C. cable to boxes, cabinets or other
equipment shall be listed and identified for use. At all points where the armor
of MC cable terminates, a fitting shall be provided to protect wires from
abrasion, unless the design of the outlet boxes or fittings is such as to afford
equivalent protection and, in addition an insulating bushing or its equivalent
protection shall be provided between the conductors and the armor. The
connector or clamp by which the type MC cable is fastened to boxes or
cabinets shall be of such design that the insulating bushing or its equivalent
will be visible for inspection. Where change is made from type MC cable to
other cable or raceway wiring methods, a box, fitting, or conduit body shall be
installed at junction points as required in 300.15.
Substantiation: AC cable and MC cable are identical types of cable, except
for the bare internal wire enclosed in the AC cables sheath. Per code, 320.40
AC cable requires an additional insulating bushing therefore MC cable should
require the same.
Panel Meeting Action: Reject
Panel Statement: Fittings approved for use with Type MC cable are designed
so that the fitting provides the protection to the emerging conductors. An
insulating bushing is not required in Type MC cable fittings. Section 300.15
already is applicable to Type MC cable.
Number Eligible to Vote: 14
Ballot Results: Affirmative: 14

 

[kwired]

This is from the 2008 but the requirement is still the same:

Panel Statement: Fittings approved for use with Type MC cable are designed
so that the fitting provides the protection to the emerging conductors. An
insulating bushing is not required in Type MC cable fittings. Section 300.15
already is applicable to Type MC cable.

Most common fittings out there are designed to be used with AC or MC.

Most MC and AC cable sheaths are about the same thing. How can they make that statement?

The plastic bushing on the end of most "snap in" type fittings does nothing to protect the conductor from the edge of the sheath, it protects the conductor from the opening on the fitting at the most.:roll:

 

[hbiss]

Guess I'm a belt and suspenders kind of guy. I agree that the fittings and sheaths are the same so I use redheads with MC. They give them to you anyway.

-Hal

 

[ActionDave]

FWIW I have seen exactly one fault on a piece of MC where the insulation was damaged at the connector and it occurred at the mouth of a squeeze tite connector, not where the conductors emerge from the sheathing.

 

[jumper]

Guess I'm a belt and suspenders kind of guy. I agree that the fittings and sheaths are the same so I use redheads with MC. They give them to you anyway.

-Hal

The sheaths are similar, but AC has a paper filler and MC has a plastic one. I wonder how much of a difference that makes.

 

[kwired]

The sheaths are similar, but AC has a paper filler and MC has a plastic one. I wonder how much of a difference that makes.

Which you cut back either filler and expose the thermoplastic covered conductors to the edge of the sheath. It is nothing but carryover from days past when there may have been more legitimate reason to put a bushing there, and has become a game for inspectors and installers to fight over it now.