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Removing Insulation Piercing Taps

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  • J.P.M.
    replied
    Originally posted by bob-n View Post
    Andy and JPM,

    Thank you. That's what I needed to know and enough to scare me away from them forever. This is the first time I've heard of actual bad experiences with them.

    To me, the idea of point-contact for very high current seems flawed, but that's just gut feel. Perhaps the manufacturer has solved the problem well enough so that, with their connector geometry, if it is used on a straight cable and if it is torqued correctly, it will work. That's a lot of ifs.

    For a typical small installer with an old load center and little or no training or experience, it seems a recipe for disaster. Even if the failure rate is a few percent, that's too risky. To make things worse, it is installed upwind of the main circuit breaker, so if it does fail, there's a huge amount of energy available to make fireworks.
    I never said they were bad. Andy probably said it better: follow mfg. instructions.

    If used properly with the right product for the right application, I'm sure the ILSCO product is fit for purpose. One problem might be a lot of folks don't follow instructions or know why such joints are more than a screw-n-go proposition. I can think of a lot of reasons why crimped joints can be troublesome that most folks, including a lot of DIY'ers aren't aware of - at least that's been my experience.

    If you're a professional and know and respect why a crimped joint needs care in design and maybe even more so when it comes to assembly, use what you've learned, as well as mfg. instructions/guidelines to complete the crimped joint, you'll most likely be OK.

    Leave a comment:


  • foo1bar
    replied
    Originally posted by bob-n View Post
    if it is used on a straight cable and if it is torqued correctly, it will work. That's a lot of ifs.
    Is it much more than: a breaker will work if the wire is stripped the proper amount and if the connector is torqued correctly ?

    To make things worse, it is installed upwind of the main circuit breaker, so if it does fail, there's a huge amount of energy available to make fireworks.
    That is one reason I'd avoid them for my own use - even though I know they can be perfectly fine when properly installed.

    To me, the idea of point-contact for very high current seems flawed,
    I think there is a fair amount of surface area of metal-to-metal contact - maybe not as much as when you torque down a wire in a circuit breaker, but I think they've gotten it so there's enough surface area that the resistance isn't very high so it can handle quite a bit of current without too much heat being generated.


    Last edited by foo1bar; 10-14-2020, 10:43 PM.

    Leave a comment:


  • bob-n
    replied
    Andy and JPM,

    Thank you. That's what I needed to know and enough to scare me away from them forever. This is the first time I've heard of actual bad experiences with them.

    To me, the idea of point-contact for very high current seems flawed, but that's just gut feel. Perhaps the manufacturer has solved the problem well enough so that, with their connector geometry, if it is used on a straight cable and if it is torqued correctly, it will work. That's a lot of ifs.

    For a typical small installer with an old load center and little or no training or experience, it seems a recipe for disaster. Even if the failure rate is a few percent, that's too risky. To make things worse, it is installed upwind of the main circuit breaker, so if it does fail, there's a huge amount of energy available to make fireworks.

    Leave a comment:


  • PVAndy
    replied
    Originally posted by bob-n View Post
    PVAndy,
    Can you share your reasons for not using them? Thank you.
    Manufactures requirements. To be code compliant you need to follow both the code and any manufacturer’s instructions. Also it is very important to only use them on straight sections of wire and torture according to specifications.

    We have seen several instances of burned up connectors that were install when the wire was not a straight section

    Andy

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by bob-n View Post
    PVAndy,
    Can you share your reasons for not using them? Thank you.
    Not speaking for PVAndy, but:

    Among other reasons, the electrical resistance of a joint that uses a reused piercing type tap will be greater than one using an new/unused tap.
    Like other compression/crimp connections the joint is, in effect, a cold weld. Once used/deformed, the tap guts will never be the same, either in dimension or mechanical characteristics.

    The reasons behind the concept are kind of similar to the reasons behind the good practice of never reusing a gasket on a flanged joint.

    Or, not expecting a set of removeable dentures to fit in a different mouth.

    Besides, considering the labor involved and its cost, connections are usually pretty far down the list of places to cheap out on materials anyway.

    If nothing else, call it cheap insurance.

    Leave a comment:


  • bob-n
    replied
    PVAndy,
    Can you share your reasons for not using them? Thank you.

    Leave a comment:


  • DanS26
    replied
    I would use this tape......an excellent product......

    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    Leave a comment:


  • PVAndy
    replied
    Originally posted by bcroe View Post
    If the insulation gaps were large, I would put some liquid tape in them. Then wrap them up
    in a few layers of electrical tape. I like heat shrink, but it probably will not go on here.
    Bruce Roe
    I agree with Bruce. Note NEVER reuse an insulation piercing tap

    Andy

    Leave a comment:


  • pjschae
    replied
    Thanks Bruce!

    Leave a comment:


  • bcroe
    replied
    If the insulation gaps were large, I would put some liquid tape in them. Then wrap them up
    in a few layers of electrical tape. I like heat shrink, but it probably will not go on here.
    Bruce Roe

    Leave a comment:


  • pjschae
    started a topic Removing Insulation Piercing Taps

    Removing Insulation Piercing Taps

    I am adding a solar circuit and reconfiguring my existing system so I won't need the previously installed load side taps anymore. I haven't found anything in NEC or manufacturer literature on removal or what to do now that the cable has been pierced. The taps are ILSCO Kupler 4/0 - #6. Can anyone guide me here?
    Last edited by pjschae; 10-11-2020, 10:27 PM.
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