Effectiveness of 1920's armored cable ground

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al hildenbrand

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Minnesota
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Electrical Contractor, Electrical Consultant, Electrical Engineer
I don't follow. Hasn't the entire discussion here been about modifying existing BX circuits?.

The opening post asks about receptacle replacement. One doesn't modify the armored cable, in my in-the-field experience with my AHJs, when replacing the receptacle device. I understand the question to be, is 250.118(8) including existing non-bonding strip Type AC cable? My answer is yes, and I've substantiated it with quotes from the NEC, NFPA, UL and UL's representative.
 

iwire

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Location
Massachusetts
The opening post asks about receptacle replacement. One doesn't modify the armored cable, in my in-the-field experience with my AHJs, when replacing the receptacle device. I understand the question to be, is 250.118(8) including existing non-bonding strip Type AC cable? My answer is yes, and I've substantiated it with quotes from the NEC, NFPA, UL and UL's representative.

Al, it is my opinion replacing a two wire with a three wire receptacle is modifying the circuit.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Al, it is my opinion replacing a two wire with a three wire receptacle is modifying the circuit.

I agree that replacing the receptacle device is modifying the receptacle device. The armored cable and junction boxes of the existing circuit are NOT altered, that is, they were installed as a grounding means and are still a grounding means, by Code, with the caveat that I have to see that "Type AC cable shall provide an adequate path for fault current" by an unspecified procedure. Replacing the receptacle device is not altering the armored cable or the boxes in my jurisdictions.
 

augie47

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Tennessee
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State Electrical Inspector (Retired)
Interesting read. I can say that after years of crawling under old houses with old BX, if there's any old BX in al's damp root cellar, I'm going to allow him to grab a hold of it to prove his point.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Interesting read. I can say that after years of crawling under old houses with old BX, if there's any old BX in al's damp root cellar, I'm going to allow him to grab a hold of it to prove his point.


Crawl spaces are rare, here. They are also, historically understood as damp locations. Almost all of the intact non-bonding strip Type Ac armored cable I experience is in buildings with basements that are dry. The damp basement of long duration tends to degrade the armored cable. But the dry basement dwelling is, by far, the most common in my Metro area.
 

iwire

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Location
Massachusetts
I agree that replacing the receptacle device is modifying the receptacle device. The armored cable and junction boxes of the existing circuit are NOT altered, that is, they were installed as a grounding means and are still a grounding means, by Code,

And that opinion is just as valid as the opinion that changing the use of the BX cable is modifying the branch circuit.

Replacing the receptacle device is not altering the armored cable or the boxes in my jurisdictions.

But is it is modifying the use of the BX and an AHJ / inspector could just as easily see it that way as yours.
 

big john

Senior Member
Location
Portland, ME
Alright, let's try this:

You have an existing 20A circuit with 15A receptacles.

You want to add a 20A receptacle to the circuit.

You find the 12-2 is old and only has an undersized #14 ground.

Since you aren't changing the conductors, and that NM was once code legal, can you wire in your 20A device?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
But is it is modifying the use of the BX.

Forgive me. I read and understand the words of your opinion that I quote here, but, you'll have to help me.

Before, the BX cable and box assembly, wired to the armored cable article 1913 NEC and later NECs is a grounding means. After the receptacle device change, the BX cable and box assembly, wired to the armored cable article 1913 NEC and later NECs is a grounding means. The BX is still used the same way.
 

iwire

Moderator
Staff member
Location
Massachusetts
Forgive me. I read and understand the words of your opinion that I quote here, but, you'll have to help me.

Before, the BX cable and box assembly, wired to the armored cable article 1913 NEC and later NECs is a grounding means. After the receptacle device change, the BX cable and box assembly, wired to the armored cable article 1913 NEC and later NECs is a grounding means. The BX is still used the same way.

Again Al, that is your opinion it is not a fact.
 

big john

Senior Member
Location
Portland, ME
...The BX is still used the same way.
What say you to that hypothetical about the undersized Romex ground?

Similar scenario: Once compliant wiring method where construction standards have since changed. Are you allowed to use it to the original design standard or do you have to follow the new ones as published?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Again Al, that is your opinion it is not a fact.
In your opinion.

But it is fact. Obviously direct unaltered quotes from multiple NEC over the last hundred years, unaltered quotes from other NFPA and UL documents and unaltered quotes from David Dini, PE, of UL in direct substantiation of my opinion is just too weak against your opinion. . .
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I don't follow. Hasn't the entire discussion here been about modifying existing BX circuits?

John, while the short-lived NM reduced-gauge ground wire question will be an interesting discussion, I think it should be another thread. But I am only speaking for my contributions, not yours. I can see there are some strong parallels in the two different wiring methods. That's all I'll say about that type of NM in this thread.
 

iwire

Moderator
Staff member
Location
Massachusetts
In your opinion.

But it is fact. Obviously direct unaltered quotes from multiple NEC over the last hundred years, unaltered quotes from other NFPA and UL documents and unaltered quotes from David Dini, PE, of UL in direct substantiation of my opinion is just too weak against your opinion. . .

Al, things that are clear facts do not stir up this much controversy. Obviously things are not as much of a fact as you feel them to be.

You tell us keep it a code discussion but then you go on at length about your experiences and such.

You tell us to keep it a code discussion and when some of us ask what we feel are relevant code questions you tell us you will not discuss those questions.

Your whole argument here has been of a man possessed to one idea and one idea only. You have closed your mind to all other possibilities.

Regardless of your opinions on the subject it is not as black and white as you are trying to paint it. :)
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Al, things that are clear facts do not stir up this much controversy. Obviously things are not as much of a fact as you feel them to be.

You tell us keep it a code discussion but then you go on at length about your experiences and such.

You tell us to keep it a code discussion and when some of us ask what we feel are relevant code questions you tell us you will not discuss those questions.

Your whole argument here has been of a man possessed to one idea and one idea only. You have closed your mind to all other possibilities.

Regardless of your opinions on the subject it is not as black and white as you are trying to paint it. :)

Character attack is a logic fallacy.

The historic Code and today's Code, along with other NFPA and UL documents I have quoted without alteration, with regards to Type AC Armored Cable, establish their own truth that is not my opinion. I am merely reporting documentation, as the basis of my holding forth here on the Forum with regards to Type AC Armored Cable.

The 320.108 adequacy of the fault current path, IN MY OPINION, can be degraded by environmental conditions, poor or failed workmanship, and/or non-Code assembly of the Type AC armored cable system. Such degradation is reason for repair and/or replacement of part, or the whole. This is true for the Armored Cable wiring method, whether constructed with a bonding strip in intimate contact with the armor, or not.

I understand the controversy, here, to revolve around blanket interpretations of inadequacy of Type AC Armored Cable that, when declared to the non-Code-trained owner of an occupancy, results in burdens that are a social justice issue.
 
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