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  • Frank DuVal
    replied
    I too use heat shrink to cover those damaged conductors. 600 volts per layer rating is good enough for me. But for abrasion resistance sometimes I use more layers if I see an issue in the box. Larry's use of new insulation covers the abrasion issue.

    Glad I sold dad's BX wired house 10 years ago!

    Leave a comment:


  • kwired
    replied
    Originally posted by hbiss View Post
    None that I know of.

    -Hal
    Nothing prohibits it either if it isn't addressed.

    I generally have used shrink tube instead of insulation from another conductor for such repairs.

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  • hbiss
    replied
    Not being a code expert, wonder what section addresses that type corrective action?
    None that I know of.

    -Hal

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  • junkhound
    replied
    Originally posted by LarryFine View Post
    Serious. What made you think otherwise?
    Admit to doing same in my mother's 120 YO house for a temp fix, but replaced run later.

    Thinking 'not serious' in context of the previous few comments on liability, code, AHJ, etc.
    Not being a code expert, wonder what section addresses that type corrective action?

    Leave a comment:


  • ptonsparky
    replied
    I’ve had to do the insulation slip trick before. Not high on my list for preferred methods, but it does the job.

    The two blacks and a white in what was a 14/2G is not mine.

    Leave a comment:


  • LarryFine
    replied
    Originally posted by junkhound View Post
    Is that post sarcasm or serious? I cannot tell. Either way, where is the added step to keep it all in place by filling he end with RTV?
    Serious. What made you think otherwise?

    I hadn't thought of sealant.

    Leave a comment:


  • junkhound
    replied
    Originally posted by LarryFine View Post
    When dealing with insulation falling off of the wires, I try to remove all I can, even into the sheath, and slip a length of the correct color of insulation stripped from modern NM onto the wire.

    If you measure it carefully, or trim it after you slide or twist it onto the bare wire, the splice will keep it fully on the wire. Sometimes, you need to use insulation from wire one size larger.
    Is that post sarcasm or serious? I cannot tell. Either way, where is the added step to keep it all in place by filling he end with RTV?

    Leave a comment:


  • jmellc
    replied
    Originally posted by peter d View Post
    Agreed, old BX with cloth and rubber insulated conductors is the single most dangerous wiring method in existence. It's far more dangerous than K&T or ungrounded first generation romex. It needs to be 100% replaced. I've had a similar experience where a short circuit on a BX wired circuit caused a huge arc flash and burned the wall as a result. I would not sleep well in a house with that danger lurking behind walls.

    I would not touch a house with BX unless it was a total rewire. It's either going or I'm not working on it.
    Originally posted by drcampbell View Post
    That's interesting and counter-intuitive. Enclosing the conductors in steel would seem to make it more safe, not less. (yes, I did read the previous posts in this thread)

    I wonder if it was less of a problem when it was popular for new installations, (which was when, 1930-1960?) when available fault currents weren't as high and panels had fuses -- which would have been somewhat current-limiting, even if the "current limiting" concept hadn't emerged yet?
    Enclosing in steel is actually part of the problem. I've usually not been able to cut BX with a rotosplitter, have to score with a hacksaw and twist to break. That bit of twisting is enough to damage conductor insulation, which is nearly always brittle to begin with. I'm all in favor of fixing what can be fixed but it's time for BX to be laid to rest. Save some for the museum (do we have one?) but scrap the rest.

    Leave a comment:


  • LarryFine
    replied
    Originally posted by kwired View Post
    . . . and the reason newer AC cable has a bonding wire under the sheath now.
    Correct. The bonding wire is not an end-to-end equipment grounding conductor, it is a turn-to-turn shorting wire. That's why it is effective despite its relatively small equivalent gauge.

    Leave a comment:


  • LarryFine
    replied
    When dealing with insulation falling off of the wires, I try to remove all I can, even into the sheath, and slip a length of the correct color of insulation stripped from modern NM onto the wire.

    If you measure it carefully, or trim it after you slide or twist it onto the bare wire, the splice will keep it fully on the wire. Sometimes, you need to use insulation from wire one size larger.

    Leave a comment:


  • kwired
    replied
    Originally posted by drcampbell View Post
    That's interesting and counter-intuitive. Enclosing the conductors in steel would seem to make it more safe, not less. (yes, I did read the previous posts in this thread)

    I wonder if it was less of a problem when it was popular for new installations, (which was when, 1930-1960?) when available fault currents weren't as high and panels had fuses -- which would have been somewhat current-limiting, even if the "current limiting" concept hadn't emerged yet?

    Current limiting of the sheath was the problem, it has high enough resistance because it is one long piece of steel, that spirally wraps around the conductors it contains. The less resistance it has the more ground fault current can flow and open the overcurrent device faster, and the reason newer AC cable has a bonding wire under the sheath now.

    Leave a comment:


  • Netpog
    replied
    Originally posted by drcampbell View Post
    I wonder if it was less of a problem when it was popular for new installations, (which was when, 1930-1960?)
    My house was built, and wired with BX, in 1934. I'm sure it was much less frightening to behold then, and for the first few decades thereafter, than it was in 2015.

    One advantage of the old stuff: no need for wire strippers. Just flick your fingernail against the desiccated rubber insulation (wrapped with brittle cloth) and you've got naked conductors.

    The ravages of time, weather, and ozone were magnified by the high-temperature luminaires that were installed mid- or late-century. And by the pure lack of junction boxes.

    Leave a comment:


  • Netpog
    replied
    Originally posted by drcampbell View Post
    That's interesting and counter-intuitive. Enclosing the conductors in steel would seem to make it more safe, not less.
    Certainly enclosing conductors in a continuous steel jacket, with a low-resistance path to ground, makes all the sense in the world.

    By contrast, enclosing live conductors in a spiral of steel, with a few-ohms of resistance between a fault and the panel, is a lovely way to save on light bulbs. Just enjoy that orange glow from the BX armor.

    Originally posted by peter d View Post
    Agreed, old BX with cloth and rubber insulated conductors is the single most dangerous wiring method in existence. It's far more dangerous than K&T.
    'Zactly. And yet it's knob & tube that gets all the bad press, and all the unpleasant attention from insurers & home inspectors.

    There's no justice.

    I would not touch a house with BX unless it was a total rewire. It's either going or I'm not working on it.
    Now that's the kind of intolerant attitude that I can respect. Hear hear!

    Leave a comment:


  • drcampbell
    replied
    Originally posted by peter d View Post
    Agreed, old BX with cloth and rubber insulated conductors is the single most dangerous wiring method in existence. ...
    That's interesting and counter-intuitive. Enclosing the conductors in steel would seem to make it more safe, not less. (yes, I did read the previous posts in this thread)

    I wonder if it was less of a problem when it was popular for new installations, (which was when, 1930-1960?) when available fault currents weren't as high and panels had fuses -- which would have been somewhat current-limiting, even if the "current limiting" concept hadn't emerged yet?

    Leave a comment:


  • peter d
    replied
    Agreed, old BX with cloth and rubber insulated conductors is the single most dangerous wiring method in existence. It's far more dangerous than K&T or ungrounded first generation romex. It needs to be 100% replaced. I've had a similar experience where a short circuit on a BX wired circuit caused a huge arc flash and burned the wall as a result. I would not sleep well in a house with that danger lurking behind walls.

    I would not touch a house with BX unless it was a total rewire. It's either going or I'm not working on it.

    Leave a comment:

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