Bx install

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Hoodood

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nyc
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Electrical foreman
I'm a commercial electrician in nyc. We just took on a new 7 story apartment building from ground up. I only use Mc on my jobs. The prints call for bx. I researched and couldn't find anything concerning the use of bx in demising walls. I thought I would reach out and see if anyone knows if bx is acceptable for this use. Thanks.
 
Hoodood said:
I'm a commercial electrician in nyc. We just took on a new 7 story apartment building from ground up. I only use Mc on my jobs. The prints call for bx. I researched and couldn't find anything concerning the use of bx in demising walls. I thought I would reach out and see if anyone knows if bx is acceptable for this use. Thanks.
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"BX" is a layman's generic term for cable with an armored spiral sheath. You can't buy actual, original BX cable any more. The original BX didn't have a bonding wire, then a flat strip was added; both proved unsatisfactory. You can buy AC cable, which has the aluminum bare bonding wire under the armor, or you can buy MC cable that has an insulated green grounding wire. There are several variations of both as well.

Probably an architect who either doesn't understand the difference between BX, AC, and MC, or one that is too lazy to update his boilerplate callouts on prints. Ask for an RFI if you're worried. I fight the "BX" battle too; armored cable all looks the same to most people, but the differences are important. Personally, I'm a fan of MC. I like the green wire.

Here's a link to a pretty good explanation though it's a bit of an add for Seatek:

http://seatekco.com/bx-cable/



SceneryDriver
 
Odd that they specify "BX" as opposed to "AC". "BX" is the registered trade name of armored cable, NEC Art 320, for General Electric, which later divested this business to Sprague Electric.
My experience is that in most situations "MC" would be acceptable but it would be best to verify.
By using the term "BX" one might assume they are simply trying to indicate that NM is not acceptable.
 
AC steel armored cable not mc

AC steel armored cable not mc

Sorry , I'm old school we call AC steel armor with no grounding conductor bx. I haven't used it in a while so seeing that on the prints made me think twice. The prints don't indicate running an insulated green wire so since steel amored AC cable is code compliant for grounding with set screw connectors I'm good to go. I was just wondering if there was any codes prohibiting this type of cable in demising walls. Thanks.
 
Hoodood said:
Sorry , I'm old school we call AC steel armor with no grounding conductor bx. I haven't used it in a while so seeing that on the prints made me think twice. The prints don't indicate running an insulated green wire so since steel amored AC cable is code compliant for grounding with set screw connectors I'm good to go. I was just wondering if there was any codes prohibiting this type of cable in demising walls. Thanks.
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not prohibited
 
There is absolutely no reason to use "BX"/AC anymore. Sure, it's code compliant but why bother with it when MC is so much better?
 
It's been my experience that in NYC people still use "BX" as a generic term for either AC or MC cable. There are differences between the two so clarification is needed.
 
jumper said:
I am not one for BX per se, but AC over MC is handy at times. Box fill and such.

I use MC far more often, but AC does have its uses.
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Try MC AP it has the armor listed as an EGC, no egc to bond, 6 ft support instead of 4 1/2, no redheads required, 30% faster to install.
 
I'm with Dennis on this, I would contact the engineer and get something in writing or, if the prints are sealed that may be enough. I'm going back a few years and dating myself but doesn't the material you use in NYC have to be approved by the Board of Standards and Appeals ? I would contact them as well just to make sure.
 
goldstar said:
I'm with Dennis on this, I would contact the engineer and get something in writing or, if the prints are sealed that may be enough. I'm going back a few years and dating myself but doesn't the material you use in NYC have to be approved by the Board of Standards and Appeals ? I would contact them as well just to make sure.
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Agree.....get it in writing, but I would get the engineer to do his job and suggest to HIM to contact the board of Standards and Appeals....if applicable.
 
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