BX, AC, MC

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DrkAngloftheNite

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North Carolina USA
A co-worker and I have a disagreement about what certain cables are made. As far as I know, BX was a name brand and not an actual cable. AC stood for "Armored Cable" and was made of a steel jacket with no ground conductor since the shielding acted as ground; MC stood for "Metal Clad" and was made of aluminum and has a ground conductor inside.

My co-worker says AC stands for "aluminum-clad" and that both MC and AC are aluminum; and also that BX is a TYPE of cable, NOT just a name brand.

Please help us clear this up.

Thanks.
 
infinity

infinity

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BX is a trade name for type AC, armored cable and is not a code recognized cable type. {Article 320}
MC is for metal clad cable and comes in steel and aluminum jacketed. Also it does not always have a wire type EGC. MC-ap has a bare bonding wire which acts in concert with the jacket to form the EGC. {Article 330}

Welcome to the Forum.
 
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mike7330

Senior Member
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North America
My understanding is BX was Bronx, NY wire company

My understanding is BX was Bronx, NY wire company

The steel armor was installed to keep the rats from eating the cable and was not an equipment grounding
Conductor at that time. Maybe some of the older guys know more!?
 
infinity

infinity

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mike7330 said:
The steel armor was installed to keep the rats from eating the cable and was not an equipment grounding Conductor at that time. Maybe some of the older guys know more!?
Click to expand...

At what time are you referring to, before the bonding strip was incorporated into the cable?
 
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Volta

Senior Member
Location
Columbus, Ohio
AFAIK, BX was the 2nd experimental cable of that sort, thus B. It would have been patented by Sprague Electric in 1902, I think, but was introduced in 1899 by Harry Greenfield. First in the NEC in 1903. It was AC for Armored Cable. Started being used commonly in the 30's. The #16 size bonding strip was required starting in 1959, though appeared earlier, in various sizes. If it doesn't have a fibrous (paper) covering around the individual insulated conductors then it isn't type AC.

From 1968 to 1978 MC and AC shared an NEC article, and were then split to more officially be different types.
 
roger

roger

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DrkAngloftheNite said:
My co-worker says AC stands for "aluminum-clad" and that both MC and AC are aluminum; and also that BX is a TYPE of cable, NOT just a name brand.

Please help us clear this up.

Thanks.
Click to expand...
Get together and read article 320 taking note of section 320.100 for AC, and then read through article 330 for MC .

Roger
 
kwired

kwired

Electron manager
Location
NE Nebraska
mike7330 said:
Yes, and at that time, receptacles had no grounds ...........
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I have seen non grounding outlets installed where metallic raceways were run that should have provided a good grounding path.

I think the receptacles had no grounds not because a ground was or wasn't available, it just was not required to install a grounding type receptacle.
 
kwired

kwired

Electron manager
Location
NE Nebraska
DrkAngloftheNite said:
My co-worker says AC stands for "aluminum-clad" and that both MC and AC are aluminum; and also that BX is a TYPE of cable, NOT just a name brand.

Please help us clear this up.

Thanks.
Click to expand...

Read 320.2 and 330.2 for definitions of each type of cable. Both specify a metallic armor, but neither puts restrictions on what type of metal armor is to be used. I have seen both in aluminum and steel armor, and would not be surprised to see other metals for armor.
 
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