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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. KF5LJW

    KF5LJW Ham Member QRZ Page

    OK sorry for the delay in posting the final installment. It is time to bring it all together. In part 1 and 2 was dedicated to constructing what is called collectively the Ground Electrode System or GES for short.

    It comprises of 3 separate sub-systems:


    • AC Service Ground
    • Lightning Protection System
    • Optional RF Radials

    Now it is time to bring it all inside the Shack, or I should say keep it outside the Shack. We want to provide a low impedance path to earth for outside faults like lightning, and prevent it from coming inside. So what we are doing if providing a planned path with low as impedance as possible to shunt unwanted current to earth, and block them from coming inside the Shack. Simple huh?

    Well it really is simple in theory, and if we use some proven techniques developed over the decades we can put it into practice. Broadcasters, Telephone companies, and Wireless Carriers have been using two techniques for decades. One is called a Single Point Isolated Ground, and the other has a few names like Integrated Ground Plane, Multi-Point Ground Plane, and Mesh. I am not going to go into the Integrated Ground Plane because it is not possible or feasible for ham operators to implement. But I will give you a mind picture to visualize it. Think instead of installing carpet on the floor, you install a copper or steel plate, metal cabinets and tables all bonded together to form a plane. OK that is it for Integrated. Let’s move on.

    Figure 1 below shows the Single Point Isolated Ground Plane (SPIGP) in its simplest forms. The Green lines indicate the Integrated Ground Plane which takes many forms like concrete, structural steel, conduits, or any unintentional ground paths current might be able to enter or exit. At first the benefit of an SPIGP may not be apparent. But here is the trick; no outside currents can flow in the SPIGP. For current to flow there must be a point of entry, and a point to exit. In other words there has to be a complete circuit for current to leave the source and return to the source.
    To use a SPIGP we must establish a Ground Window for all conductors to pass through before entering and leaving the SPIGP. A Ground Window is a hypothetical "opening" which all electrical conductors enter or leave. Physically the Ground Window is say a copper buss bar or a sheet of galvanized sheet metal fixed to a piece of plywood.

    On this Ground Window we will install Surge Arrestor devices. The surge devices include AC TVSS, telephone line and data surge arrestors, secondary coax lightning arrestors, etc… Any cable that comes into or leaves the Shack. It also allows us a place to terminate any ground conductors needed like bonding an antenna tuner or transceiver.

    OK building the Ground Window or Surge Reference Equalizer is pretty easy and straight forward. It needs to be placed at the point of entry where your coaxes enter the Shack. It can be as simple or elaborate as you want. For my setup it is just a simple copper buss bar mounted on the wall with isolators I salvaged from an old cell site. Another good method is using a piece of ¾-inch plywood with a piece of galvanized sheet metal affixed to it.

    On the Surge Reference Equalizer you will physically mount all your surge arrestor devices mounted on it starting with a quality AC Term strip with built in TVSS. The important thing to remember is all devices need to have a steel or conductive case because it will be the physical electrical connection to ground. The only wires or straps needed will be the connection to the outside GES, and radio equipment like an antenna tuner or transceiver.

    Let’s talk a bit more about an AC TVSS as it is very important. You need to find units that comply with ANSI/IEEE C62.41 Class A TVSS and listed UL-1449 Second Edition. In addition you may also want to consider a ANSI/IEEE C62.41 Class A TVSS device installed on you Main Breaker Panel, or even better a unit on the Electric Meter Pan, called a collar purchased via your electric utility. It takes about 1-minute to install one at the Meter. The Class A TVSS device will protect everything in the house.

    OK back to the AC TVSS for the shack. Here is a line I really like made by Tripp-Lite models IB8RM or IBAR4. They have 8 and 4 NEMA 5-15 receptacles respectively. The IB8RM specs include:


    • 3840 Joules
    • 97K Amp capacity ANSI/IEEE C62.41 Class B/C
    • UL-1449 Second Edition Listing
    • 40db EMI/RFI isolation between receptacles and AC source.
    • $50,000 Ultimate Lifetime Insurance (USA & Canada Only)

    Other surge protectors to be installed on the Surge Reference Equalizer are for any cables that enter/leave the shack. For example data/telephone lines and secondary coax surge arrestors. Primary surge arrestors are installed outside just before entering the structure. Again be sure to use arrestors with steel or conductive cases.

    OK all that is pretty much it. I hope I answered all you questions, but if you have any questions or comments please feel free to ask or comment. Just keep it constructive. As a bonus I have included some photos at a cellular cell site for you to see how it is done commercially.

    73’s To You

    Dereck
    KF5LJW


    Part 3 Surge Reference EQ.jpg GEC.JPG Hatch Plate 2.JPG Hatch Plate.JPG
     
    Last edited: Mar 19, 2012
  2. KD5SPX

    KD5SPX Ham Member QRZ Page

    Anybody who has a grounding system like you have shown ... has way too much money to be in ham radio and wouldnt need a grounding system since they could easily replace everything lost from a catastrophe with there abundance of money as long as it wasnt their life!

    If lightning hits I dont give a damn what you have in place it will cause damage to everything anyway ... this has been shown time and time again!!
     
    N9TGW and W5ACC like this.
  3. KF5LJW

    KF5LJW Ham Member QRZ Page

    Thank you for your constructive comments. FWIW every cell site in the USA is hit directly frequently with no damage incurred. So there might be something to it you have over looked.

    In addition what was covered in Part 1 and 2 is required by electrical code. If you cannot afford to do that, you cannot afford to be a ham. If you failed to meet code and your home is damaged, your insurance carrier has some really bad news for you. "Your Are Not Covered. Have a nice day".

    The Tripp-Lite unit will cover $50K of your radio equipment for an initial investment of $50 to $90. Not to expensive IMHO
     
    Last edited: Mar 19, 2012
  4. K8MHZ

    K8MHZ Ham Member QRZ Page

    Really?

    Have you ever seen a large ham radio repeater?

    The pics posted could be of our '94 repeater. It is housed in building with public service, television and commercial radio repeaters. The coax is hard line and routed just like the pics. They also enter the building in the same manner.

    The site has operated flawlessly, it's 350 foot tower taking direct hits, for decades. The ham radio gear is owned by our local club and the space is donated by the people that own the site and the tower.

    Cell sites also operate while taking direct hits.

    Stick with the thread and I'll bet you will find that Dereck will have suggestions for us hams to come close to emulating the stoutness of a commercial installation for less cost, but using the same approaches.

    Edit to add:

    I have also been in privately owned control buildings made solely for ham radio. Check out W8SS here on QRZ. That is a 200 foot tall rotating tower. The coax enters the building at the bottom of the tower in the same manner as the pics that Dereck posted.
     
    NL7W and KM4TIN like this.
  5. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    This was good and informative, thanks for posting that....
     
  6. AG6JU

    AG6JU Ham Member QRZ Page

    some day I like to have good outdoor antenna, and this post helped me stay out of future trouble other wise I would got into. thanks for info.
     
  7. K9KJM

    K9KJM Ham Member QRZ Page

    WRONG!

    It CAN be done on a low budget: http://www.scribd.com/anon-849269/d/14868226-lightning-protectiontaming-thors-thunderon-a-budget

    And as pointed out by many who know, Most all stations including tall repeater towers, Commercial broadcast, Police, Fire, Cellphone, etc. ARE hit by direct lightning strikes most every storm with NO damage to equipment, And more important, No injury to humans.

    Thank You to LJW for a great series of articles with good information.

    Boo and Hiss to those like SPX who continue to spread falsehoods and old wives tales!
     
  8. WD5JOY

    WD5JOY Ham Member QRZ Page

    Dereck has attempted to point out (quite well) the imperatives (required by "code" in one form or another) we should at least consider. While it may appear as if he issuing a 'decree' it is far from that; he is offering 'free information' in an easy to understand format for our consideration.

    Those who choose to make a diligent effort to 'understand the information' and perhaps (hopefully) follow it to at least the minimum level will surely benefit. Those who feel it is a wasted effort, not worth the effort or that they are doomed to suffer a catastrophic level of damage will ignore his 'advise / suggestions / knowledge' and go about operation in a manner they feel is adequate for their station (and wallet).

    Personally, I find his information quite helpful in that it allowed me to assess my own station integrity and improve as I see fit. Rather than belittle his suggestions, suggest they are too costly or impossible to implement, those who disagree might do well to offer alternatives - based on something other than a "I am doomed so why even try" philosophy. Beyond that, they have nothing but the negative to offer and obviously never learned the value of the words, "Thank You" as they should be applied to Dereck and others who have offered questions and suggestions to enhance the value of this series of informative 'articles' (again - FREE and without any other expectations).

    THANKS DERECK AND OTHERS WHO "CHIMED IN" WITH GREAT INFORMATION!

    Donald - WD5JOY - The "old man" in the old-folks home - 73
     
    Last edited by a moderator: Mar 22, 2012
    W1ADE likes this.
  9. K9STH

    K9STH Ham Member QRZ Page

    SPX:

    There are things that can be done to help reduce the chances of taking a lightning strike. However, there is nothing now known in the industry that can absolutely prevent a strike. All that aside, PROPER grounding can prevent any damage from a strike in most situations and minimize the damage in the remainder.

    Proper grounding doesn't mean spending a lot of money. It does mean paying attention to detail. There is a BIG difference. Having spent a little over 10-years as a telecommunications consultant with TXU (your electric company, at least in terms of the actual delivery, in Venus, Texas), I have seen grounding installations for which a "pretty penny" was spent by TXU that were absolutely useless and grounding installations that were done on a budget that were very effective. One of my principle tasks was the grounding systems for the two-way radios (over 300 base stations), for the microwave radio systems, and for the data centers. When I was first employed, TXU was suffering hundreds of thousands of dollars in losses due to lightning strikes every year. When the telecommunications department was eliminated in mid-1999, those losses had been basically reduced to zero! The very few incidences of lightning damage were confined to things like telephone protector blocks (which cost less than $1 each) and were due to lightning strikes on the telephone company lines over which TXU had absolutely no control.

    A large number of the microwave "huts" were installed by a single company who "thought" their grounding techniques were excellent. Wrong! The ground system was "pretty", lots of "right angles" in the wires, etc. The metal conduits of the AC wiring were not actually connected to the ground system, and other things were also not correct. It was possible to go into a microwave "hut" and see where there had been all sorts of arcing caused by not properly installing the ground system.

    Because of budgeting, revising the grounding system over almost half the State of Texas, took several years. However, by the time the grounding systems had been reworked, the losses due to lightning strikes dropped to basically zero.

    Depending on the individual site, improving the grounding system cost from just a few dollars to thousands of dollars. But, TXU was paying a premium price to get the job done properly and within certain time constraints. An individual amateur radio operator can invest his/her time with a minimal cash outlay for materials and get an excellent grounding system. It doesn't matter how much, or how little, money that the operator has. It does matter how much that operator really desires to protect his/her investment no matter how large or how small.

    Glen, K9STH
     
    W1ADE likes this.
  10. WB5UMG

    WB5UMG Platinum Subscriber Platinum Subscriber QRZ Page

    KF5LJW Like others have posted, I appreciate your time and effort in posting this valuable article, Like another post, I spent 39 yrs in the communication business and most in cabling, have seen so many variable that lightning has injected in every form of weird situation! Best one can do to protect is whatever you can afford and hope for the best.
    In replacing my coax 213U, because of loss at PL 259's, would it be jake leg to just cut a small window in outer sheath of coax, place a copper strap under the sheath,waterproof and connect it to ground wiring just before entering shack. Telco had a strap device thingy with a stud coming out of it to slip under cable sheath for bonding, wish I had some, they would do what I am describing. Its O.K. to slap me silly if you desire :-((.
    73's and Tnx fer your time!
    Dee
    WB5UMG
     

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