MC Anti-shorts

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chris kennedy

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Location
Miami Fla.
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60 yr old tool twisting electrician
I had a guy I work with tell me you don't need to use an anti-short on MC if you use connector with an insulating bushing. For ex. an Arlington SG 38 A has the bushing built in. So we looked around 330 and 110. I have always used the anti-short without much thought. Is this industry standard or manufactures recommendation?
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
I always use the redheads-- they are to protect the cable from the sharp edges of the mc cable. I am not sure how an insulated throat would do that since that is past the jacket.
 

iwire

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Location
Massachusetts
You are never required by the NEC to use an antishort bushing.

We must use MC fittings and all MC connectors are designed to be used without additional plastic bushings.
 

roger

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Location
Fl
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Retired Electrician
Anti Short bushings are not required on MC, however they are required on AC, see 320.40 and 330.40

Roger
 

Chris6245

Senior Member
Location
Ohio
The NEC 2005 only requires anti-short bushings for type AC cable. It does not even mention type MC (for anti-short) that I have found. The "installation instructions" for most MC cable only "recomends" the use of anti-short bushings and I have not found a manufacturer the "requires" the use of anti-short bushings. I still have my electricians use them, it's just good practice. I do have inspectors say they are "required" but I have yet to have one show me where it say's that
 

mdshunk

Senior Member
Location
Right here.
Almost nobody removes the MC cable armor properly anyhow, particularly if you use a RotoSplit type tool with no additional squaring operation. Use of an anti-short bushing might serve some remedial purpose with MC cable when the armor was improperly removed.
 

mdshunk

Senior Member
Location
Right here.
chris kennedy said:
How many electricians in the US?
Not nearly enough. The Bureau of Labor Statistics predicts that by 2014, the need for electrical workers will be at about 734,000 persons. That's 78,000 beyond the number currently employed in the electrical field. Presently, there are slightly less than 37,000 people enrolled in various apprenticeship programs.
 

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
My emotion says to use the redhead, my logic says not required. Have not seen an article yet about things "blowing up" do to the lack of redheads yet. I worked in a high vibration area last year, wjth C1D1 and CID2 areas (TMC and TMCX connectors) The C1D1 areas had a compound to center, and hold the individual conductors in place. The C1D2 inter space connects, had nothing to to keep to the wires centered when the connections were tight. The MANUFACTURER DOES NOT MAKE IT MANDATORY, so we need to watch what industrial accidents may be caused IF ANY in the future reports from the industry. I'm stuck in neutral, but favor the redheads in vibration prone areas.

Thanks Bob and Marc for the links.
 

mdshunk

Senior Member
Location
Right here.
Rockyd said:
I'm stuck in neutral, but favor the redheads in vibration prone areas..
I still use them anyhow. Seems wrong not to, even if they're not expressly required. Some connectors do a better job of holding the conductors centered away from the armor, that's for sure. The MC connectors that have an oblong slot at the end of the connector stop rather than a round hole don't do as good of a job holding the conductors centered. With that style of connector, I make sure I use red heads.
 

iwire

Moderator
Staff member
Location
Massachusetts
mdshunk said:
I still use them anyhow. Seems wrong not to, even if they're not expressly required. Some connectors do a better job of holding the conductors centered away from the armor, that's for sure. The MC connectors that have an oblong slot at the end of the connector stop rather than a round hole don't do as good of a job holding the conductors centered. With that style of connector, I make sure I use red heads.

^^^ What he said. :cool: ^^^
 

mdshunk

Senior Member
Location
Right here.
georgestolz said:
Is there some basis for this statement, or is it your opinion? :)
No, it has basis. Read NEMA's RV-1, "Application and Installation Guidelines for Armored Cable and Metal-Clad Cable", section 3.6.7.2.

http://www.nema.org/stds/RV1.cfm#downloadhttp://www.nema.org/redirect/redirectFile.cfm?id=10418&filename=/RV1.pdf

Pay particular attention to Figure 3.3, where a the typical result of stripping armor with a Roto-Zip with no additional squaring operation is shown as incorrect.
 
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Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
For stripping, especially where there is a lot of it, (like in an MCC or Switchboard) I like the knifes with 1/2 the blade serrated, 1/2 standard. ring the wire with the serrated edge and bend out any aluminum that appears to be crimped in with the minni needle nose. The aluminum face is at least flat that way, whereas with a roto-cutter, there is vertical cut in the MC. Be interesting to hear from others.
 
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