What Kind Of Cable Was This?

Eddie702 said:
Many get bent out of shape about it but from personal experience it will trip a circuit breaker if you get a fault. Do you really think the dinky aluminum strip does much?
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That aluminum strip is not the EGC, it supplements the spiral type sheath by shorting between turns. It doesn't even need to be terminated, it's only purpose is to sit outside any fillers within the cable and to be in contact with the sheath to assist in lowering resistance of the sheath.

Take a one foot piece of cable sheath and unwind it. It will be much longer than one foot, now imagine how much longer a 100 foot run is if you unwind the sheath of it. That is what you potentially can have for a return path if not many of each turn doesn't have incidental contact to shorten the path. Is not that an overcurrent device won't trip at all, is about having as low of impedance path as possible. There has been cases or signs of this old AC cable heating up when subject to fault current.
 
@kwired
Agree 100%. My point is this old wiring method was allowed and so was K & T and other old, outdated wiring methods. Then they were not allowed to be installed any longer, but I have never seen a case where you were forced to remove an old wiring method that was still in service. And I have never seen proof that the older BX was not allowed as an equipment ground even though we all know it is an inferior one.

As far as the aluminum strip I fold it back over the red head to hold the RH in place and wrap it around the armor before installing the connector.

But as you mentioned this is not required and it can be simply cut off.
 
Eddie702 said:
@kwired
Agree 100%. My point is this old wiring method was allowed and so was K & T and other old, outdated wiring methods. Then they were not allowed to be installed any longer, but I have never seen a case where you were forced to remove an old wiring method that was still in service. And I have never seen proof that the older BX was not allowed as an equipment ground even though we all know it is an inferior one.

As far as the aluminum strip I fold it back over the red head to hold the RH in place and wrap it around the armor before installing the connector.

But as you mentioned this is not required and it can be simply cut off.
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The older AC cable with no bonding strip, as I believe was mentioned earlier in this thread, was used at a time when installing EGC's wasn't a common thing. The bonding strip was added around the time when GEC's were being required for everything. Again existing equipment has generally been allowed to remain as is if it was code compliant at the time of install.

I wouldn't be against GFCI protection on old AC cable, it will trip at low fault current level, certainly this armor can carry a few milliamps of fault current and likely trip faster than if there were significant enough resistance to lengthen trip time of a standard breaker. I think it should be a design decision and not necessarily code requirement though.
 
kwired said:
The older AC cable with no bonding strip, as I believe was mentioned earlier in this thread, was used at a time when installing EGC's wasn't a common thing.
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Correct. I don't think grounding receptacles were even invented yet because there was nothing that had a grounding plug on it that would use it. About the only things you had to worry about was metal wall plates and fixtures possibly becoming energized which the grounded armor would take care of by blowing the fuse.

At around the late 50's I believe the first appliances that had grounding plugs were washing machines that extended the EGC to the utilization equipment. That made those grounding adapters infamous, or they just cut the ground pin off.

-Hal
 
Thinking some more about those washing machines of back then- I remember cold water washing machine hoses having a grounding conductor built into them. They were marked to only be used on the cold.

-Hal
 
The NEC began requiring EGC wires in NM cable back in 1974, and at the same time required a ground bonding strip IN the armor in AC (Armored Cable) OR a ground wire, which became MC.

The term AC for Armored Cable goes all the way back to the beginning, existing alongside K&T, but being more expensive, was uncommon in residential. The first BRAND of AC was released in the first decade of the 1900s, called “Greenfield” cable, a name that is still used in some circles today. Sprague Electric of New York, the mfr, was bought by GE in the 20s and GE experimented with different ways of manufacturing Greenfield. They settled on two types, AX and BX, and yes, the “X” stood for experimental. BX won out in market popularity (I don’t know the differences). But technically, BX is still a brand name (like Romex), it was/is still called AC if it has a ground bonding strip embedded in the metal corrugations, and MC if there is a separate ground WIRE in it. I believe you can buy “BX” brand both ways, so it no longer denotes which TYPE of cable it is.
 
Jraef said:
The NEC began requiring EGC wires in NM cable back in 1974, and at the same time required a ground bonding strip IN the armor in AC (Armored Cable) OR a ground wire, which became MC.

The term AC for Armored Cable goes all the way back to the beginning, existing alongside K&T, but being more expensive, was uncommon in residential. The first BRAND of AC was released in the first decade of the 1900s, called “Greenfield” cable, a name that is still used in some circles today. Sprague Electric of New York, the mfr, was bought by GE in the 20s and GE experimented with different ways of manufacturing Greenfield. They settled on two types, AX and BX, and yes, the “X” stood for experimental. BX won out in market popularity (I don’t know the differences). But technically, BX is still a brand name (like Romex), it was/is still called AC if it has a ground bonding strip embedded in the metal corrugations, and MC if there is a separate ground WIRE in it. I believe you can buy “BX” brand both ways, so it no longer denotes which TYPE of cable it is.
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I don't know but I had read that the bonding strip in the BX started around 1959 when grounded receptacles where required. As far as NM goes I saw undersized grounds in the 60. I assume grounds in NM was required at the same time as BX
 
kwired said:
NM cable from 60's through 80's had a tougher sheath as a general rule than many the cables made since ~2000. Today's cable you have to be careful pulling across the floor or over top of the bottom chord of a truss rafter during installations, if you rub against some metal object it may tear the sheath much easier than it would have most those older cables.
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When I take stuff to the dump, I like to go dig through the copper scrap that people drop off. Last week I found some nice examples of Essex and Etcoflex. The house my dad built in 74 was all wired with Etcoflex, so I was happy to see that. It was about 10' of 12/3. The paper and PVC sheeth are so much heavier. It almost looks like 8/3 wire of today.
 
Jraef said:
The NEC began requiring EGC wires in NM cable back in 1974,
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Seems kind of late, sure it wasn't maybe 1964?

But then I do recall seeing 12-3 with no ground into the 1980's even and 10-3, 8-3 and 6-3 with no ground at least until 1996 NEC when they started prohibiting use of grounded conductor to also bond the frame of the appliance on ranges and dryers.
 
Jraef said:
The NEC began requiring EGC wires in NM cable back in 1974, and at the same time required a ground bonding strip IN the armor in AC (Armored Cable) OR a ground wire, which became MC.

The term AC for Armored Cable goes all the way back to the beginning, existing alongside K&T, but being more expensive, was uncommon in residential. The first BRAND of AC was released in the first decade of the 1900s, called “Greenfield” cable, a name that is still used in some circles today. Sprague Electric of New York, the mfr, was bought by GE in the 20s and GE experimented with different ways of manufacturing Greenfield. They settled on two types, AX and BX, and yes, the “X” stood for experimental. BX won out in market popularity (I don’t know the differences). But technically, BX is still a brand name (like Romex), it was/is still called AC if it has a ground bonding strip embedded in the metal corrugations, and MC if there is a separate ground WIRE in it. I believe you can buy “BX” brand both ways, so it no longer denotes which TYPE of cable it is.
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I grew up in a house built in 1964 and wired with NM cable and all of the outlets were grounded.
 
herding_cats said:
All the old timers I worked with called it BX. Get rid of it. It's not safe. It was a bad idea from day one.
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I know far superior type MC cab!e cost more then type AC ( ya BX ) but wish they prohibit using BX anywhere but maybe a 24 volt alarm system. Over my 50 years have seen too pieces of flimsy BX that armored jacket was rushed thru . Nothing beats a copper ground wire . Maybe 15 years ago at a continuing education clsss learned how the term BX came about. The B was for the second type they were experimenting with and the X was for experimental. Think all old timers know that Romex was the name Rome wire company used for their type of NM cable.
 
robertd said:
I grew up in a house built in 1964 and wired with NM cable and all of the outlets were grounded.
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Lots of builders chose to use ground wires, it just wasn’t required. Even in 1976 when I started, you had to specify if you wanted a ground wire by ordering “14-2 W/G”, and if you didn’t say the W/G, you got 14-2 with no ground wire. Now, it’s the opposite.
 
Jraef said:
Lots of builders chose to use ground wires, it just wasn’t required. Even in 1976 when I started, you had to specify if you wanted a ground wire by ordering “14-2 W/G”, and if you didn’t say the W/G, you got 14-2 with no ground wire. Now, it’s the opposite.
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The change to equipment grounding in 250-91(b) was in the 1968 NEC they added the language recognizing the sheath as a EGC “For conductor enclosures and equipment only” the armor of type AC metal clad cable” and I think UL had started requiring the strip possibly as far back as 1962. Also of note there was a separate code article on 'ALS cable' which is now what we call 'MC light' or the Aluminum sheathed MC.
Also MC cable first appeared in the 1962 NEC.

There was very old post on there where someone posted a photo of some glowing BX cable I cant seem to find it.
 
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When were grounded three-slot receptacle outlets first required?​

Wednesday, July 11, 2018
The National Electric Code (NEC), which specifies the standards for electrical installations, is dedicated to safety and fire prevention. Every three years the code is revised and updated, and the 1962 edition of the code was the first to require that all 120-volt electric receptacles in a home be three-slot. That third, rounded slot provides grounding, which decreases the risk of electrical shock—or even electrocution—when using an appliance that is also properly wired.
The NEC gradually ramped up to this standard, beginning in 1947 with the requirement of three-slot receptacles in the laundry only. Then the 1956 edition of the code expanded the required three-slot outlet locations to include outdoors, garages, and basements. They were going for the wet locations first, where a person was most likely to be shocked, before raising the standard all the way six years later to include the whole house.
 
Jraef said:
Lots of builders chose to use ground wires, it just wasn’t required. Even in 1976 when I started, you had to specify if you wanted a ground wire by ordering “14-2 W/G”, and if you didn’t say the W/G, you got 14-2 with no ground wire. Now, it’s the opposite.
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Just in the last 2-3 years I realized I don't have to say "with ground" at supply house

When I started (late 70s) we would often have both on job, since switches and lights didn't need a ground
 
I have never seen a home insurance complain nor mention BX cable, many homes in the Boston area contain it. BX or MC is still required for an oil furnace along with a red switch plate.
I carry a 10/32 tap with an extension so I can tap a ground screw into the old black metal boxes that have this stuff when replacing switches, receptacles, dimmers etc I often do this.
I have probably replaced 100's of non-grounded outlets with grounding type by tapping and threading 10/32's and a pig tial installed on old black metal boxes that contain the BX, you cant tell if that bond strip is there or not but all the outlets test as grounded when I am done.
I have never installed a GFCI just because its BX.
The one thing it does not work on is occupancy sensors, I have burned up about a dozen occupancy sensors when I switched out toggle switches to sensors in a large office building wired with the old BX.
 
pipe_bender said:
I have never seen a home insurance complain nor mention BX cable, many homes in the Boston area contain it. BX or MC is still required for an oil furnace along with a red switch plate.
I carry a 10/32 tap with an extension so I can tap a ground screw into the old black metal boxes that have this stuff when replacing switches, receptacles, dimmers etc I often do this.
I have probably replaced 100's of non-grounded outlets with grounding type by tapping and threading 10/32's and a pig tial installed on old black metal boxes that contain the BX, you cant tell if that bond strip is there or not but all the outlets test as grounded when I am done.
I have never installed a GFCI just because its BX.
The one thing it does not work on is occupancy sensors, I have burned up about a dozen occupancy sensors when I switched out toggle switches to sensors in a large office building wired with the old BX.
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I agree with everything you said except the part about "BX & MC required for an oil furnace along with a red switch plate. I have been an oil tech in MA for 52 years. The feed to the furnace and the emergency switch and the firomatic switch can all be wired in NM and the NM is usually sleeved down to the furnace or boiler. The controls mounted on the boiler or furnace if field wired have to be AC, MC or greenfield and there used to be something in the old MA oil burner code (which no longer exists) that AC,MC or Greenfield had to be 18" or less.

The red switch plate only applies to the emergency switch mounted outside the basement and is only required on oil. Unless it is a commercial job where ASME CSD_1 applies.
 
Yeah ok interesting thanks for the clarification.
I only mentioned that because I just got dinged Friday in a town I don't usually work in, it was a old oil burner switch I moved, it was BX that I yarded out, at the top of a basement stairs during a remodel.
They replaced and widened the stairwell so I ran new NM cable.
The inspector emailed me that the code section was "2023 NEC section 724.31 and 725.31 in the older code books." i did not fight him on it as I am not familiar with these.
 
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