Station Grounding Question

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB5CC, Mar 3, 2019.

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  1. KB5CC

    KB5CC Premium Subscriber QRZ Page

    I read somewhere that some people bury the grounding rod horizontally about 3 feet deep when they live in places like I do where it's very difficult to drive the rod 8 feet deep vertically. There was also a comment about pouring rock salt on top of the rod before shoveling the dirt back in.

    Does anyone here have experience with that approach and what are your thoughts?
     
  2. KV6O

    KV6O Ham Member QRZ Page

    Ground rods may be driven in on a oblique angle not greater than 45 deg. from vertical. If that's not possible, you can place them horizontally in a trench at least 30 feet deep, perpendicular to the building. (NFPA 70-2017, Article 250.53) . GEM, or Ground Enhancing Material can be used as well - google it.
     
  3. KC8VWM

    KC8VWM Ham Member QRZ Page

    Thing is a ground rod is supposed to be installed into "undisturbed" soil.

    This is not only because it's a stated electrical code requirement, but it's also because the density of undisturbed soil is much higher and therefore offers lower resistance making it a far more effective ground.
     
    Last edited: Jun 15, 2019
  4. KV6O

    KV6O Ham Member QRZ Page

    Yes, but if it's not possible, there are alternatives. There are several listed grounding electrodes allowed by the NEC. The goal is for than less than 25 ohms to earth for the NEC electrical ground... lower is better!
     
    Last edited: Jun 15, 2019
  5. KC8VWM

    KC8VWM Ham Member QRZ Page

    Correct.. The primary objective is to achieve the lowest resistance possible. Regardless of the method used to bury a ground rod, resistance should actually be checked and measured to ensure this has been effectively achieved.
     
  6. KV6O

    KV6O Ham Member QRZ Page

    And the funny thing is the NEC says that if you can't get 25 ohms, add a second ground rod. That's it. No need to check or do anything else. So, if you're unsure, or unable to measure the resistance, you just add another ground rod and you meet code regardless of what the actual resistance is. Obviously, AHJ's might say differently, but it seems that most that adopt the NEC leave that in place. :rolleyes:
     
    KC8VWM likes this.
  7. KC8VWM

    KC8VWM Ham Member QRZ Page

    I see.

    I prefer to ensure my ground system, is an effective ground system.

    Perhaps my offer of assistance and advice has been helpful.
     
    KV6O likes this.
  8. KV6O

    KV6O Ham Member QRZ Page

    Should have read 30" deep, not 30 feet deep! :eek:
     
  9. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    I'm needing some clarity. Read the other posts here and other sites, left confused with some questions
    Recently had the first near strike (in 20yrs) way ahead of a storm in a freshly plowed, flat farm field, so not feeling so lucky anymore.

    Conditions here: no antenna grounding at this point, always disconnect during a storm. Feed HF wire antennas through a relay box and a separate coax for the 6M dipole mounted part way up a 65' tower. I buried all wires back to the shack 95' away.
    Going to ground the tower off the legs and bond all cables to that point.

    Bonding the shack to the electrical is the confusing part.
    The house has 3 - #14 wire so for electrical safety its grounded to the panel.
    The service is grounded to the incoming water pipe with #10 stranded
    Bell & Catv are bonded 32' downstream to the 3/4" copper cold water pipe.
    The shack is another 18' downstream from that and I'd put a ground rod where all the external wires enter the shack .
    From here there are at least 12 soldered elbows & Tees on the copper pipe back to the panel ground
    If I bond the shack equipment to the water pipe do these solder joints diminish the bond and since the rigs are case grounded through the outlets and will it cause ground loops.

    Kind of torn with bonding the tower to the house since its 95' away and I disconnect the rig.
    Dont want to encourage a tower hit coming to the house - rather bleed that out there
    yet the utilities ground their incoming wires and those coaxial cable lightning arresters would satisfy that

    what to do...
    Bob VE3CGA
     
  10. AH7I

    AH7I Ham Member QRZ Page

    Step potential will lead to holes in the outer insulation of wire/cable lying on the ground.
     

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