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#87388 - 02/26/04 01:12 PM MC/BX
SteveMc Offline
Member

Registered: 02/05/04
Posts: 61
Loc: Rock Hill, SC
Is there a difference or just different names for the same thing? If so, then when did the name change occur? Just curious.

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#87389 - 02/26/04 03:12 PM Re: MC/BX
Jim M Offline
Member

Registered: 08/10/01
Posts: 453
Loc: Chestertown, MD, USA
Although they look similar the MC cable will have a insulated ground wire, the AC or BX as commonly called relies on the metal jacket and the bond wire.

Red heads or anti-short bushing are required with AC but not MC.

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#87390 - 02/27/04 03:24 AM Re: MC/BX
gunther Offline
Member

Registered: 09/17/03
Posts: 59
I had never heard that anti-shorts weren't required with MC. They always come with the rolls of MC from the manufacturers that we get and I know they are required in this area. (Digging out code book)

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#87391 - 02/27/04 07:11 AM Re: MC/BX
SteveMc Offline
Member

Registered: 02/05/04
Posts: 61
Loc: Rock Hill, SC
Thanks, Jim, for the quick reply. It settled an argument. As for red heads, that's an ongoing discussion in another forum as well. I use them simply because it's not a lot of trouble and I had a cable blow up in my face once because it was nicked and didn't have a red head. Whoever installed it probably didn't use a Roto-splitter.

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#87392 - 02/27/04 08:02 AM Re: MC/BX
Thom Offline
Member

Registered: 08/23/02
Posts: 24
Loc: Westfield
I also use the red heads but I do believe it is not a code requirement until about 10 AWG. 12 and 14 AWG I don't think you have to.

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#87393 - 02/28/04 05:24 AM Re: MC/BX
Reel-Break Offline
Member

Registered: 04/04/02
Posts: 179
Loc: nc
Here`s a link to anti shorts not required.How ever I still think small price to pay for no returns.We use them.
http://www.nema.org/DocUploads//8B117E35-EFF9-4B09-B6E4722E1E6DFEF3/BULL90.pdf

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#87394 - 02/29/04 10:54 AM Re: MC/BX
electure Offline

Member

Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA
Good Job, Reel-Break!
I've been looking for something like this for a long time.
I've checked UL, not required.
I contacted AFC and AlFlex both about this; the answer was the same.

"The bushings, though not required, are supplied as an additional means of protection"

Good enough for me...I use 'em.

BX is AC Cable= Bushings always required
MC is MC Cable=Not required, but supplied for free.
You guys make your own decisions as to the value of your time.

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#87395 - 03/04/04 10:19 AM Re: MC/BX
Anonymous
Unregistered


When I started in the trade BX was not used and AC-MC was not yet on the market.
I have been "told" that BX casing can not be used for a ground and the fittings are not rated for grounding. As in retrofitting a ground pigtail in the back of a metal box to change old two wire receptacles to grounding type receptacles using the metal case as a grounding means....Any thoughts?

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#87396 - 03/04/04 12:43 PM Re: MC/BX
tdhorne Offline
Member

Registered: 03/22/01
Posts: 344
Loc: Maryland, USA
 Quote:
When I started in the trade BX was not used and AC-MC was not yet on the market.
I have been "told" that BX casing can not be used for a ground and the fittings are not rated for grounding. As in retrofitting a ground pigtail in the back of a metal box to change old two wire receptacles to grounding type receptacles using the metal case as a grounding means....Any thoughts?


If the cable in question does not have a bonding strip to insure the continuity of the spiral wound interlocking cable armor you cannot use the armor as an Equipment Grounding Conductor.
--
Tom H
_________________________
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison

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#87397 - 03/04/04 01:26 PM Re: MC/BX
Anonymous
Unregistered


Thanks Tom,
So then wouldn't "BX" be considered the non grounded armored cable made until some time in the 60's? early 70's? And, was it no longer recognized by the NEC because of the grounding issue? I don't remember seeing AC cable until some time 80's. I know that armored cable disappeared for years and if it was a grounding issue I wonder why they didn't just put a full size ground conductor in it and keep it on the market.

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