In a recent post it was indicated that MC does not need anti short bushings. I used to live near Chicago, everything was EMT so I never cared. But now being in Washington I see MC a lot. I have not been able to find information to settle the matter, and where I've worked so far, I've been asked to use them. From what I've seen, isn't whether the bushing is required or not determined by the fitting used?
MC and Anti Short Bushings
- Thread starter wolfman56
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roger deas
Member
- Location
- North_Carolina
Re: MC and Anti Short Bushings
Wolfman56, go to this link,
http://www.nema.org/index_nema.cfm/1427/3D9675D4-0FA8-4439-A04AFC9E0DDBC994/
click on "Use of Anti-Short Bushings for Terminating Type MC Cable" under "Complimentary Documents"
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Roger
Wolfman56, go to this link,
http://www.nema.org/index_nema.cfm/1427/3D9675D4-0FA8-4439-A04AFC9E0DDBC994/
click on "Use of Anti-Short Bushings for Terminating Type MC Cable" under "Complimentary Documents"
You will have to register to see this article.
Roger
Re: MC and Anti Short Bushings
Wolfman,
You Should Definitely Install An Anti-Short Bushing When Installing MC Cable. I Have Run Into (3) Instances Within The Last Year That The Neutral Wire Was Damaged And Caused An Elevated EMF Due To Not Installing The Anti-Short Bushing. One Instance Caused Problems With The Computer Monitors In The Area And The Other Two I Found As I Was Doing A Pre-Punch On A Building (Using A Gausmeter).
-Ed
Wolfman,
You Should Definitely Install An Anti-Short Bushing When Installing MC Cable. I Have Run Into (3) Instances Within The Last Year That The Neutral Wire Was Damaged And Caused An Elevated EMF Due To Not Installing The Anti-Short Bushing. One Instance Caused Problems With The Computer Monitors In The Area And The Other Two I Found As I Was Doing A Pre-Punch On A Building (Using A Gausmeter).
-Ed
charlie
Senior Member
- Location
- Indianapolis
Re: MC and Anti Short Bushings
Ed, it seems to me that you are using insulated bushings on all EMT connectors as well.
Why not be careful with the installation instead of damaging the insulation during the installation?
Ed, it seems to me that you are using insulated bushings on all EMT connectors as well.
Why not be careful with the installation instead of damaging the insulation during the installation?Re: MC and Anti Short Bushings
Charlie,
What Happened In All Three Cases Was The Jacket Of The MC Cut Into The Neutral Conductor Either When It Was Being Pushed Up Into The J-Box Or During Installation (I am Not Exactly Sure When It Happened) But In All Three Cases There Was Not An Anti-Short Bushing Installed.
-Ed
Charlie,
What Happened In All Three Cases Was The Jacket Of The MC Cut Into The Neutral Conductor Either When It Was Being Pushed Up Into The J-Box Or During Installation (I am Not Exactly Sure When It Happened) But In All Three Cases There Was Not An Anti-Short Bushing Installed.
-Ed
chris white
Member
- Location
- Pennsylvania
Re: MC and Anti Short Bushings
Definitely not required by the NEC, only on Type AC. But, some local inspectors require them anyways, and they usually come free with each coil, so why not use them?
Some connectors already have an insulated bushing built in, and often using a separate anti-short along with this kind of connector makes it hard to install the cable in the connector properly. So in that case, I'd say leave it off. But otherwise, using the standard connectors, I always use them. A few seconds more in labor, and it can save a lot of potential downtime and troubleshooting. Even if one person takes extra care installing the cable(without the bushing), another person could come behind with the splices, installing devices, etc., and twist that wire across a sharp surface.
Definitely not required by the NEC, only on Type AC. But, some local inspectors require them anyways, and they usually come free with each coil, so why not use them?
Some connectors already have an insulated bushing built in, and often using a separate anti-short along with this kind of connector makes it hard to install the cable in the connector properly. So in that case, I'd say leave it off. But otherwise, using the standard connectors, I always use them. A few seconds more in labor, and it can save a lot of potential downtime and troubleshooting. Even if one person takes extra care installing the cable(without the bushing), another person could come behind with the splices, installing devices, etc., and twist that wire across a sharp surface.
chris white
Member
- Location
- Pennsylvania
Re: MC and Anti Short Bushings
An additional comment--I think most of the problem with MC conductors getting knicked is not with listed single or duplex connectors, but when the cable is terminated in boxes with internal clamps.
An additional comment--I think most of the problem with MC conductors getting knicked is not with listed single or duplex connectors, but when the cable is terminated in boxes with internal clamps.
garrisonm1
Member
- Location
- Maryland
Re: MC and Anti Short Bushings
To me I believe that the roll of mc when you purchase it comes with anti short bushings, so in that case I beleive the manufactor recommends you install them or they wouldn't supply them.
To me I believe that the roll of mc when you purchase it comes with anti short bushings, so in that case I beleive the manufactor recommends you install them or they wouldn't supply them.
goldstar
Senior Member
- Location
- New Jersey
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- Electrical Contractor
Re: MC and Anti Short Bushings
Bridgeport makes an MC fitting called "EZ Lock". It has a built-in bushing at the head end. If you try to install the "red head" it will not fit properly into the connector nor will it fit if you try using it with AC type cable that has a shunt wire. In addition it does not use a lock nut to secure it to the box or panel. Instead it's a pressure type clamp that spreads the head end inside the box once you tighten down the screw. They take up a lot less room than most other types of MC connectors. I think they're great and I use them exclusively for MC applications.
Bridgeport makes an MC fitting called "EZ Lock". It has a built-in bushing at the head end. If you try to install the "red head" it will not fit properly into the connector nor will it fit if you try using it with AC type cable that has a shunt wire. In addition it does not use a lock nut to secure it to the box or panel. Instead it's a pressure type clamp that spreads the head end inside the box once you tighten down the screw. They take up a lot less room than most other types of MC connectors. I think they're great and I use them exclusively for MC applications.
Re: MC and Anti Short Bushings
Goldstar, we use these also as well as the AFC connectors. I agree they are great and the AFC connector specifies an "anti short bushing" is not required when it is used.
I do have a question though. How does the ground strip have a bearing on the MC connector fitting on AC?
The ground strip can be cut off flush with the end of the cable sheath.
Roger
Goldstar, we use these also as well as the AFC connectors. I agree they are great and the AFC connector specifies an "anti short bushing" is not required when it is used.
I do have a question though. How does the ground strip have a bearing on the MC connector fitting on AC?
The ground strip can be cut off flush with the end of the cable sheath.
Roger
goldstar
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
Re: MC and Anti Short Bushings
Roger,
Good point. I guess you could cut the shunt wire off flush with the end. I'm so accustomed to wrapping it around the coil of the armor that I didn't think of that.
Roger,
Good point. I guess you could cut the shunt wire off flush with the end. I'm so accustomed to wrapping it around the coil of the armor that I didn't think of that.
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