BX as a ground.

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mivey said:
I know Wayne did, for one.
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In post 159, I asked if unbonded BX cable is currently a Chapter 3 wiring method, and then I asserted that if it is not, replacement is the only option when dealing with it.

No one has really followed up on that. Not having given it much consideration, I think unbonded BX cable meets the NEC definition of MC cable. So it can be left in place if treated as MC cable, as iwire has done in his basement. :)

Cheers, Wayne

P.S. As I hope has been apparent, I have started using the phrase "unbonded BX" as a shorthand for "BX cable without a bonding strip". Since we have been talking about using the "unbonded BX" for grounding, I figured there would be no confusion.
 
wwhitney said:
I really do want to get this right, so I understand your position, it is possible I'm misunderstanding.

BTW, is there any way to fairly easily see the entire history of 406.4(D)(1) through the ages?
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I think I understand this, by the nature of your questions. But, I can't really afford all this time that it takes to repeat the contents of the Code, both historic and current, that it has taken me a long time to read and digest.

I respectfully ask that you undertake that task. Kevin (480Sparky) has a spreadsheet based matrix of some rules across the editions. . .it is highly instructive, as it allows one to quickly go to the original text. . .IF you have the text, i.e., copies of the old editions of the NEC. I've spent a long time assembling mine, and reading, and talking. . . all of which is informing a portion of my posts in this thread.

Some of the earliest editions of the NEC, about the first dozen, have been available for download, but I don't have a link that is viable, today.

I'm far from any kind of expert. And, except for the actual NEC texts that I post, all of my comments are only my opinion. . . so my opinion and a buck will get me a cup of low cost coffee.

wwhitney said:
But I'm happy to call the NEC debate a draw if you agree with the proposition in post 272.
Post 272 said:
existing unbonded BX cable armor used as a grounding means is an "actual hazard to life, health or property," as its high impedance presents an unacceptable risk that during a ground fault the OCPD will not trip. This could easily lead either to a shock hazard (hot frame of equipment) or a fire (from excessive heating of the armor).
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Respectfully, your proposition is another thread.
 
al hildenbrand said:
Yes, to the OP scenario, 406.4(D)(1). Asked and answered . . .
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406.4(D)(1) says "The NEC is a NEW construction standard," really? Can you help to see that? Because I see language talking about replacement, which says (edit: to me) the NEC covers repairs and modifications as well as new construction.

Cheers, Waye
 
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al hildenbrand said:
But, I can't really afford all this time that it takes to repeat the contents of the Code, both historic and current, that it has taken me a long time to read and digest.
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Oh, I'm not asking you to, I was asking if there was a relatively easy way (for me) to see the history of 406.4(D)(1). From what you describe, there isn't. I don't have any library of NEC copies.

Cheers, Wayne
 
K8MHZ said:
I think you will find that steel AC has a copper bonding strip, . . .
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Hal's point about dissimilar metals still stands. Cu and Fe are different valences.

As you emphasize the point, Marky, I pause to reflect on my anecdotal observations, and I seem to recall a lot of steel sheathed AC internal bonding wire and strip that had to have been something lighter and "whiter" than copper. Just sayin'. But I have never examined any one product's metallurgy, so I really can't say for sure.

hbiss said:
Ground faults within the boxes and wiring are common. Don't you think that back when BX came into use they were just as smart as we are now and if the OCP (fuse) wouldn't be able to protect they would have figured it out? I think it worked just fine when it was new. So why the problem now?
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Hal, what you are asking about is part of my cognitive dissonance here, in my work area of three million souls and a fair sized number of subdivisions, municipalities and infill occupancies and additions/remodels all wired with AC type-BX. I don't see the Metro erupting into flames. My comment is purely anecdotal. . . and entirely to the side of the NEC citations I have focused on in this thread.
 
George Stolz said:
why keep entertaining a debate?
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At the risk of responding at all, You guys could benefit from getting together on your approach. Bob and Wayne have been tag teaming me for NOT responding. . .

George Stolz said:
The fourth page of the code already referenced regarding superseding.
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The opening sentence of the last paragraph on page 4 of the 2014 NEC says, "This Code is purely advisory as far as the NFPA is concerned." Hmmm. I have to wonder if adopting jurisdictions include any of this page as enforceable language in their statutes. . .

George Stolz said:
250.4.
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"Prescriptive". Miriam-Webster simple definition is: giving exact rules, directions, or instructions about how you should do something.

That's a good word. In a receptacle replacement in an existing Outlet on an existing Branch Circuit connected to etc. etc. what is it that one is to "do". In the OP scenario, as I have doggedly refused to be distracted from, one starts by going to 406.4(D) and lands, again, in the OP scenario, at 406.4(D)(1). But, I am repeating myself, and you've carefully read my main points, I'm sure. So 'nuff said.

George Stolz said:
You'll never see it because you refuse to;
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Oh, I "see" your perspective perfectly, and I honestly can't believe that you don't, in turn, "see" the legal landmines it creates out in the world of installed wiring, from a Code perspective. As badly as the safety argument compels you to condemn BX before you consider receptacle replacement, I submit that perspective is not supported by the Code.
 
al hildenbrand said:
At the risk of responding at all, You guys could benefit from getting together on your approach. Bob and Wayne have been tag teaming me for NOT responding. . .
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Tag teaming you? I have been really limiting my posts here and you where asked two direct, yes or no questions that I still have not seen you answer in a direct way.
 
iwire said:
you where asked two direct, yes or no questions that I still have not seen you answer in a direct way.
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Forgive me. I haven't intentionally not responded, rather, I suspect the questions might have been more nuanced than you think. Try again.
 
iwire said:
I don't believe Wayne at any point has suggested that existing untouched circuits need to be removed.
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The OP was asking that and it seems that Wayne, Peter, and some others seemed to fall into that camp.

Do you believe replacing a receptacle also requires replacing the original BX branch circuit?

The OP was proposing installing a GFCI breaker at the panel and three-prong receptacles. As far as the wholesale replacement theme, how did this become any different than installing three-prong outlets on K&T?
 
Personally, i find the theoretical aspects of BX debate fascinating here, as i have a 30yr history of having to deal with it.

But as an EC , the paultry price of a $50 dual purpose breaker creating compliance vs. a rewire is a no brainer...

~RJ~
 
iwire said:
Keep that in mind every time you go to mention how they do things where you are.
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I took that to mean that in his area they have enough cases that the AHJ deals with it regularly so may have some unique insights as opposed to areas that are not as old and don't see as much of this stuff.


They have figured out that BX was a code recognized grounding means. If you read Al's posts and links you should see that.

Would I use routine branch-circuit BX today to clear a ground fault? No.

Would I install a GFCI breaker and three-prong outlets? Yes.

Was BX ever a code accepted grounding means? Yes.
 
romex jockey said:
Personally, i find the theoretical aspects of BX debate fascinating here, as i have a 30yr history of having to deal with it.

But as an EC , the paultry price of a $50 dual purpose breaker creating compliance vs. a rewire is a no brainer...

~RJ~
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Probably have to fill up the whole panel the way they wired back then. As I said in an earlier post suppose you have a bulldog pushmatic, or maybe a Federal Pacific. Then will the bank like all those stickers on each outlet as they try to sell the place.
 
romex jockey said:
Personally, i find the theoretical aspects of BX debate fascinating here, as i have a 30yr history of having to deal with it.

But as an EC , the paultry price of a $50 dual purpose breaker creating compliance vs. a rewire is a no brainer...

~RJ~
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Key is dual purpose. A simple AFCI breaker without GFP is worthless.
 
mivey said:
The OP was asking that and it seems that Wayne, Peter, and some others seemed to fall into that camp.
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No, that has never been my position.

Do you believe replacing a receptacle also requires replacing the original BX branch circuit?
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If your intent is to have a grounded receptacle, then yes, the BX must be replaced because it's no longer recognized by the NEC as an EGC. Therefore rewiring is one option, or simply install a 2-wire receptacle. That has been my position on this from the very beginning.

The OP was proposing installing a GFCI breaker at the panel and three-prong receptacles.
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I'm comfortable with that arrangement since the BX armor won't be carrying much fault current as the GFCI will (hopefully) react very quickly, mitigating any inductive heating hazard on the BX armor.

Simply relying on the BX armor as an EGC is unacceptable because it's a code violation.

As far as the wholesale replacement theme, how did this become any different than installing three-prong outlets on K&T?
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K&T is obviously an ungrounded system so there is no debate there. The great debate here is whether BX armor is a legitimate EGC or not.
 
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