Grounding Do's Don'ts & Why Part 3

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KF5LJW, Mar 19, 2012.

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  1. WR2E

    WR2E Ham Member QRZ Page

    add inability.

    Gettin' old is a b1tc4!
     
    Last edited: Jun 18, 2019
  2. W9JEF

    W9JEF Platinum Subscriber Platinum Subscriber QRZ Page

    Since US 412 went through, I rarely travel Hwy 68, but the other day, I checked, and there's 3-phase about a mile away in that direction (west).

    We cool our home with 2 window a/c units, plugged into opposite phases, effectively running on 240. When the Volt is charging (at 120 v), we use the microwave, etc. on the other side. Throughout the house we eliminate current through the neutral as much as possible.
     
  3. KF5LJW

    KF5LJW Ham Member QRZ Page

    That is the way it is suppose to be done and required by code for Sparkies to wire everything up splitting 120 volt loads between L1/L2. Granted it is impossible to balance the loads and there will always be some Neutral current flowing back to the transformer, but if wired to code and done correctly, you can keep neutral current to the transformer fairly low. What you cannot control is what the utility does, and even if you did balance the load perfectly has absolutely no effect in utility neutral current.

    Would be nice to see the USA change change operating voltages to 240 VAC. Requires no change in infrastructure and would solve all kinds of problems on the user end. Would be a pretty simple phase in today, since most gizmos can already work on either 120 or 240. Lighting could be an issue in the short term. Electronics no problemo.
     
  4. KF5LJW

    KF5LJW Ham Member QRZ Page

    Exactly and with proper planning and understanding no more expensive in most installations that are half half baked. You gave a good example of using copper water pipe as a buss bar.

    Another great true story is I have done a lot of Mission Work, some in India in villages where a lot of people are killed and injured by lightning. They live in huts with dirt floors and trees nearby. When lightning strikes a tree nearby, many residence are injured and killed. It was very easy to remedy and cost almost nothing to fix using a Ground Ring. We gathered any kind of wire we could get our hands on, Fence wire, telephone wire, mattress springs, you name it all salvaged. Dug a shallow trench around the huts and problem solved. The Ground Ring shunted all surface current around the huts thus minimizing Step Potential Difference along the surface to tolerable levels. Still get letters from Villagers on work we did 25 years ago.


    I would add to that is myths, ignorance, and "that is the way I have always done it wrong". Great example of all 3 is operators completely misunderstanding the term Isolated Ground thinking that means not connected to the utility or any other ground system. Even see that ignorance from equipment manufactures like CNC and VFD.
     
    Last edited: Jun 18, 2019
    W9JEF likes this.
  5. KA5TDA

    KA5TDA Platinum Subscriber Platinum Subscriber QRZ Page


    The correct web site is http://www.scribd.com

    Search for Lightning-Protection-Taming-Thors-Thunder-On-a-Budget

    [Direct Book Link: https://www.scribd.com/document/235324002/Lightning-Protection-Taming-Thors-Thunder-On-a-Budget - Moderator]
     
    Last edited by a moderator: Sep 23, 2019
  6. W9JEF

    W9JEF Platinum Subscriber Platinum Subscriber QRZ Page

    We have a 40 foot deep, 3 foot diameter hand-dug well with about a foot of water at the bottom. How good a ground would a 12-inch diameter ring of quarter-inch copper tubing, with multiple #12 copper wires spread about the periphery to the top be? I'm thinking of rerouting the 240 volt service to this point, and a whole house surge protector, before it gets to the house.
     
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    I'd say you're treading new ground with this one. I doubt there's an electrical code on the planet, much less in the US that would recognize such a grounding system. Sure, common sense says it would probably make a good central ground point at least for basic AC safety reasons but I doubt you'd find any way to accurately predict how well it would actually work and you might struggle to find an electrical inspector or P.E. that would sign off on that project. I suppose you could build the system and then test it with a Megger but you're really moving away from well characterized and typical grounds with this one.
     
    W9JEF likes this.
  8. W9JEF

    W9JEF Platinum Subscriber Platinum Subscriber QRZ Page

    KUOA, where I was CE, had a 450 foot tower, with a 200 foot deep well as a ground. We had one lightning hit that made holes in the 4-inch FM antenna copper coax. Blew a few diodes in the AM transmitter, but no serious damage. A friend had a lightning hit, and the only damage was a well pump. Seems intuitive that lightning would seek the best ground.

    Here in rural Arkansas, we are our own inspector. :)
     
  9. K7TRF

    K7TRF Premium Subscriber QRZ Page

    That certainly makes things easier ;)
     
    W9JEF likes this.
  10. W6KCS

    W6KCS Ham Member QRZ Page

    If you don't intend to fill the hole, I think the wires would have a lot of inductance over that length, so I wouldn't think it would be very good at all. If you plan to fill the hole, probably a better ground than you need, but probably doesn't meet code.
    I'd just use two 8' rods at least six feet apart because it's easy and no resistance measurements are needed. I hear radials improve lightning dissipation.
     
    W9JEF likes this.

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