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Joined: Jan 2004
Posts: 10
koz-man Offline OP
Hello All,

Does anybody have an idea how BX cable got the name BX? [Linked Image]

I have heard a couple of theories and was wondering if any one from this forum can add their option.

The theories I have heard are in a acronym trivia quiz I wrote at funtrivia. Here is a link to my quizzes. I'm sure you will do well on them.

Acronyms used in the Electrical Field

Residential Wiring 101

Hope you enjoy them. Feedback welcome. [Linked Image]


Sorry I should have posted this in the general section. I'm still learning.
[This message has been edited by koz-man (edited 05-23-2004).]

[This message has been edited by koz-man (edited 05-23-2004).]

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Joined: Feb 2002
Posts: 840
According to David Shapiro's "Old Electrical Wiring," the name BX is a trademark owned by GE. The name is short for "Bronx" because GE had a manufacturing facitlity to make the cable there.

AC is the technically correct name for "BX" as BX is considered slang.


[This message has been edited by CTwireman (edited 05-23-2004).]

Joined: May 2002
Posts: 1,716
Frank, that's a nice site. [Linked Image]


Joined: Mar 2004
Posts: 391
I've also heard that it was an abbreviation for "Bronx", because that is where it was produced, though I didn't know GE manufactured it.

I always think of BX as that ancient "armored cable" with the cloth-insulated conductors and no equipment ground, though I know a lot of folks use the terms "AC" and "BX" interchangeably.


Joined: Jun 2003
Posts: 1,143
BTW - "EMF" can also stand for Electro-Magnetic Field"

BTW, BX (Type AC) is still made - the fact that it's not used by anybody but old timers and DIY'ers is a testament to good PR and eae of use of Greenfield (FMC)! Check out the following link:

Cool site, and good introductory quiz!

Joined: Dec 2003
Posts: 886
BTW, BX (Type AC) is still made - the fact that it's not used by anybody but old timers and DIY'ers is a testament to good PR and eae of use of Greenfield (FMC)

Don't know where you are from (Chicago?) but I can tell you I am neither an old timer nor a DIYer (well OK, getting close to being an "old timer") and I use AC all the time around here!


Joined: Jun 2003
Posts: 1,143
No 'fense intended, Hal! Just another "jursidictional difference" showin' up.

Up in the northern Chicago suburbs ("Pipeville") , you essentially need AHJ approval to run BX anymore. They want existing runs converted to conduit within 2' of the wall in most towns around me. Gone are the metal coil home runs following floor joists in the basement like wild schools of eels.

In addition, fished lines must be flex (greenfield, FMC, MC), not BX/AC, in most of those communities.

Joined: Dec 2003
Posts: 886
No 'fense taken, that's what I thought. Awhile back one of our guys from your area sent us a bunch of pictures of a house he just roughed in EMT. Amazing, I love it!


Joined: Nov 2001
Posts: 75
I found this explanation on the website ""
Much like the invention of 3M Post-it-Notes, BX was an unintentional invention. During a production run of GREENFIELD flexible conduit, a machine malfunctioned and partially pulled some packaging twine through the conduit as it was being manufactured. Knowing that electricians in the field pulled wire through their flexible metal conduit, the Greenfield Company recognized the potential of this product and perfected the process of applying armor around electrical wires. There are several stories about where the term BX came from but my favorite is that “B” stood for product line B and the “X” stood for experimental. It was recognized by UL in 1899 under their Standard #4. The picture shown here is from the 1924 B&R Electric Supply catalog. When first invented, it consisted of a hot and a neutral Type R rubber insulated wire with a cotton-braid to protect the insulation and was sold in wire sizes #18 through #10 on the B&S or (AWG) gauge. Later innovations included a flat wire strip or bonding wire, individually paper wrapped conductors and 60 degree type T wire. For wet locations a lead covering was wrapped over the wires and was called “BXL”

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