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Thread: Re-Bar Connection

  1. #1
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    Re-Bar Connection

    Recently, on multiple projects there have been requirements for The EC to provide exothermic cadweld of ground conductors to the re-bar however I know there are acceptable compression clamp methods, multiple EC's recently have mentioned issue with the ground conductor and cadweld "holding" after the cadweld process even after multiple attempts. Just curious on everyones thoughts and experiences this is there any type of prep of the rebar that need to take place in order for the cadweld to hold better to the re-bar?

  2. #2
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    We've found that by pre-heating the mold with a torch raised our Cadweld success rate considerably. Why would someone require Cadwelding when the rebar is tied together with tie wire? Seems like a clamp listed for concrete encasement and for rebar should be sufficient.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  3. #3
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    Quote Originally Posted by infinity View Post
    We've found that by pre-heating the mold with a torch raised our Cadweld success rate considerably. Why would someone require Cadwelding when the rebar is tied together with tie wire? Seems like a clamp listed for concrete encasement and for rebar should be sufficient.
    It is sufficient but it's not as sexy as far as designers are concerned.

    Roger
    Moderator

  4. #4
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    Clean, rust, dirt, off with a wire brush, heat both the rebar and the Cadweld mold with a torch. Make the water run out of the mold. Clamp and dam with duct seal add proper shot or kcup fire it off. I only had problems when doing them in the rain with a piece of shipping wrapper as a tarp and didn't have that much trouble.
    Clean and heat is a must.
    AMP(Tyco) makes a pressure clamp, or did.

  5. #5
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    We recently had a presentation by ERICO on Cadwelding and our structural engineer, told us that almost all of the re-bar being used in A60 and should never be heated or welded on. He said that includes an exothermic connection to the rebar. He will include an extra section of re-bar that is not part of the structural design where the electrical designer has called for a cadweld connection to the rebar, and the exact connection point is spelled out on the design documents.

    He advised that if you don't have the approval of the structural engineer of record, you should be using a mechanical connection for this application. There are a number of clamps listed for this application.
    Don, Illinois
    (All code citations are 2017 unless otherwise noted)

  6. #6
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    Quote Originally Posted by don_resqcapt19 View Post
    We recently had a presentation by ERICO on Cadwelding and our structural engineer, told us that almost all of the re-bar being used in A60 and should never be heated or welded on. He said that includes an exothermic connection to the rebar. He will include an extra section of re-bar that is not part of the structural design where the electrical designer has called for a cadweld connection to the rebar, and the exact connection point is spelled out on the design documents.

    He advised that if you don't have the approval of the structural engineer of record, you should be using a mechanical connection for this application. There are a number of clamps listed for this application.
    With that info and a quick Google search, I say you/they are correct.

    It seems that there are weldable types of rebar, but not A60.
    "Electricity is really just organized lightning." George Carlin


    Derek

  7. #7
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    Quote Originally Posted by jumper View Post
    With that info and a quick Google search, I say you/they are correct.

    It seems that there are weldable types of rebar, but not A60.
    Yes, and from what our engineer told us, almost all of the rebar used in the US is A60.
    Don, Illinois
    (All code citations are 2017 unless otherwise noted)

  8. #8
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    Quote Originally Posted by don_resqcapt19 View Post
    We recently had a presentation by ERICO on Cadwelding and our structural engineer, told us that almost all of the re-bar being used in A60 and should never be heated or welded on. He said that includes an exothermic connection to the rebar. He will include an extra section of re-bar that is not part of the structural design where the electrical designer has called for a cadweld connection to the rebar, and the exact connection point is spelled out on the design documents.

    He advised that if you don't have the approval of the structural engineer of record, you should be using a mechanical connection for this application. There are a number of clamps listed for this application.

    Great info...

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