Exothermic Ground Rod

Discussion in 'Amateur Radio News' started by N5HZR, Sep 1, 2018.

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  1. KB7LMT

    KB7LMT Ham Member QRZ Page

    Great.....Now where are the marshmallows?:)
     
    KK5JY and N5HZR like this.
  2. K8XG

    K8XG XML Subscriber QRZ Page

    The chemical looks to me like Copper Thermite, which is used for Railroad Rail welding and Igniting Solid Very Large Rocket Motors
     
    N5HZR likes this.
  3. W1YW

    W1YW Ham Member QRZ Page

    Yes.
     
    N5HZR likes this.
  4. W5HEH

    W5HEH XML Subscriber QRZ Page

    HEY TNX FOR SHARING THIS , BUT RATHER THAN SPENDING EXTRA BUCKS ON WATEVER FANCY ETHO PRODUCTS , WILL USE EXISTING MATERIALS ON OUR HUMBLE HOMESTEAD - PROPANE BOTTLE TORCH AND SOLDER , IF GUD ENOUGH FOR INSURANCE , FB !!! (FINE BUSINESS )
    WHAT HELPED ME WAS CLAMP WILL GET BLOWN APART , WILL GETTER DONE THIS WEEK .
    AJ "HAMHILLBILLY " ,
     
  5. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    When I was a practicing PE the NEC allowed soldered connections for everything but ground connections.
     
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  6. KC2PMM

    KC2PMM Premium Subscriber QRZ Page

    Hello, the Cadweld method is a simple, cheap, fast way to make ground connections that will pretty much last forever, with no fear of blowing apart or melting during a lightning "event". The temps reached can easily reflow expensive silver solder, arc the connection, and blow it out.
    It's best to not advocate for methods that are unreliable and could be prone to causing damage in an "event".
    Soldering ground connections will not work just at the moment when you need them the most.
    Guy,
    KC2PMM
     
    N5HZR and KX4O like this.
  7. N8OX

    N8OX Subscriber QRZ Page

    I am a Quality Assurance evaluator for the DOD (DISA). We check grounding system and lightning protection subsystems (LPS). MIL-STD 188-124B requires grounding systems to use 10-foot 3/4" copper-clad steel spaced no further than 20 feet apart. The rods are to be interconnected using 1/0 AWG bare copper cable buried at least 18" deep 2-6 feet outside the drip line of the structure. The cable is to be brazed or welded (includs exothermic bonds). The LPS is connected to the grounding system. Soldering is not recommended for theses systems as a lightning strike will also cause high heat and the solder joint (including silver solder) may fail. I don't know if I'd trust an insurance person's evaluation... I'm sure they're not experts in the field. It's your equipment you are trying to protect. BTW, when we test a ground system we are looking for a reading below 10 ohms. The IEEE requires 5 ohms or less except in the case where a telephone switch is housed... that is 2 ohms or less. We also test using the fall-of-potential method. Any other method is not as accurate... especially a clamp on ohmmeter.
     
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  8. K8MHZ

    K8MHZ Ham Member QRZ Page

    How long ago was that? The NEC does and has allowed soldered connections, BUT the solder can't be the means of mechanical connection. An example would be wires twisted together for the mechanical connection, and solder over that.

    From a 1990 NEC "Soldered splices shall first be so spliced or joined as to be mechanically and electrically secure without solder and then soldered"

    For connection to electrodes: "The grounding conductor shall be connected to the grounding fitting by exothermic welding, listed lugs, listed pressure connectors, listed clamps or other listed means. Connections depending on solder shall not be used."

    28 years is as far back as my NEC book collection goes, but I will bet that the above has been in the NEC for many decades. I would love to be proved wrong with an excerpt from an older version of the NEC.
     
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  9. WA7PRC

    WA7PRC Ham Member QRZ Page

    My PE's drawings specified bare 2/0 stranded wire.
    I rented a crimp tool to make three connections:
    [​IMG]
    Terminal hardware and brackets are stainless steel. :)
     
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  10. K8MHZ

    K8MHZ Ham Member QRZ Page

    That is not exothermic bonding. From Wiki:

    "Exothermic welding, also known as exothermic bonding, thermite welding (TW),[1] and thermit welding,[1] is a welding process that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current."
     
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