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| I was talking with a general contractor of sorts today, and he mentioned that lots of times guys who are taking short cuts don't put on a needed red sleeve on the cable when using prewired flex. He said that the red sleeves should be visible in/near/adjacent to cable in the receptacle boxes.
I'd appreciate it if someone could expound on this. Thanks. |
Follow-Up Postings:
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- Posted by dave007700 (My Page) on Wed, Feb 24, 10 at 17:50
| Not required although I use them. |
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- Posted by neil_allen (My Page) on Thu, Feb 25, 10 at 15:43
| I believe that type AC does require use of the bushings ("sleeves") at terminations -- at least the 2008 Code -- NEC 320.40. |
Here is a link that might be useful: Illustration of 320.40
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- Posted by dave007700 (My Page) on Thu, Feb 25, 10 at 18:28
| Guess I should have asked AC or MC. MC doesn't require it. I guess because of the insulated ground? |
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| I thought the purpose of the 'red devils' was to keep the insulation on the wires from being nicked/cut by the jagged edges of the metal sheathing where it has been cut to length on the job. Is MC manufactured that differently than AC? |
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- Posted by plumeriavine (My Page) on Thu, Feb 25, 10 at 19:07
| That Illustrated NEC Guide looks really helpful. Wish it weren't $70. What is the difference between MC and AC - - MC = metal conduit? AC ? |
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- Posted by dave007700 (My Page) on Thu, Feb 25, 10 at 19:23
| Armored cable uses the metal sheath as the equipment grounding with a built in bonding jumper and mc metal clad has an insulated grounding conductor. Using the proper connectors for mc the conductors are held straight away from the jacket. But like I said I still use the red bushings regardless. Looks cleaner. I was on a job once where the contractor sent a note in the checks that they weren't needed and to send them back to the shop. That produced a good laugh. |
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| "Using the proper connectors for mc the conductors are held straight away from the jacket." This. The MC clamp has a smaller diameter exit for the wires, and does not allow them to rub against the cut ends of the armor. It is a much newer design, and eliminates the need for the red anti-short bushings. I rarely use AC but go through a decent amount of MC for both commercial and residential work. |
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- Posted by dave007700 (My Page) on Fri, Feb 26, 10 at 17:13
| I've only seen AC used once and surprisingly it was recently. Must have gotten a deal or something? I know you save a conductor, but is it worth it knowing one failed connection and you loose your ground? |
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| "... is it worth it knowing one failed connection and you loose your ground?" No worse than many other methods. The set screw on an AC box connector makes a good connection to the armor, and the bonding strip ensures a connection despite the multiple loops and joints in the armor. The MC with a run ground can allow isolated grounds when they are needed, but that extra wire costs $. There is also smooth welded MC that is not spiral wrapped but uses aluminum tube for the armor and has a very small cross section for the cable when space is at a premium. Barely more than 1/4 inch for a 14/2 cable. |
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