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  • Electric fence security question...

    Since my hobby electronics knowledge merely consists of trial & error, I thought of better asking you Profis, before my fence idea kills an intruder.
    Inside my house fence I thought mounting an electric fence barrier, consisting of a super simple circuit. I reckon it should be quite safe or is it?
    Please have a quick check on it, if there's something lethal. Thank you in advance for your expert advice.
    Attached Files
    Last edited by jjj; 07-29-2015, 02:39 PM.

  • #2
    yikes! too simple!

    The typical electric fence has tiny 20kV pulses of ~10msec at 1Hz, any more and this thing will kill. I believe its only the pulses short duration that make it nonlethal.

    See circuits here:
    A Homemade Fence Charger, Energizer Circuit Explained | Homemade Circuit Projects

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    • #3
      [QUOTE=jjj;391949]...before my fence idea kills an intruder. Inside my house fence I thought mounting an electric fence barrier, consisting of a super simple circuit. I reckon it should be quite safe or is it?
      Please have a quick check on it, if there's something lethal.../QUOTE] I have experience with electric fences. I strongly recommend that you simply purchase a commercially available unit.

      Comment


      • #4
        what Tom said!
        Patriot PE2 Fence Energizer - 0.10 Joule-819957 - The Home Depot
        Click image for larger version

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        $28

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        • #5
          And you should read up on installing the fence wiring that will be electrified. You cannot just connect the energizer to an existing fence.

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          • #6
            Originally posted by tedmich View Post
            what Tom said!
            Patriot PE2 Fence Energizer - 0.10 Joule-819957 - The Home Depot
            [ATTACH=CONFIG]35035[/ATTACH]
            $28
            Sounds great... yet, on eBay it says: 110V (...we got 220V) "May not ship to Chile"...
            So, it sounds bad!!!

            The next best offer (12V input) then is: US $64.79, plus shipping: $51.25 , plus import charges: $35.53
            Total... a cheap: $151+ (Hell, forbid!)
            Last edited by jjj; 07-28-2015, 11:28 PM.

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            • #7
              Originally posted by Tom Phillips View Post
              And you should read up on installing the fence wiring that will be electrified. You cannot just connect the energizer to an existing fence.
              I like to fit it onto the inside my property side of the high fence and label it with a scull & two bones plus faces of Mao, Hitler, & Stalin... or Isis
              If then still some idiot tries to enter... it will serve him right! I already build and applied this circuit for several years at Quilpue and taxi drivers called my house: "La fortaleza!"

              Comment


              • #8
                Originally posted by tedmich View Post
                yikes! too simple!

                The typical electric fence has tiny 20kV pulses of ~10msec at 1Hz, any more and this thing will kill. I believe its only the pulses short duration that make it nonlethal.

                See circuits here:
                A Homemade Fence Charger, Energizer Circuit Explained | Homemade Circuit Projects
                Yes, I saw this one too, but I searched for something even simpler to build. Also, it doesn't say how many joules it spits...?
                Whereas my super-simple circuit idea is adjustable from a low tick to higher Triac ticks... Maybe the low tick will be quite safe? How to guess or measure its output?
                Last edited by jjj; 07-28-2015, 11:45 PM.

                Comment


                • #9
                  I'm sorry you feel so unsafe, I'd recommend you don't try to make anything so dangerous and unsophisticated that it might kill an innocent neighborhood (or your own ) kid.

                  If it kills you, no problemo, at least you'll be at peace

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                  • #10
                    If commercial electric fences killed, you would have a lot of dead farmers and hunters.
                    They are used everywhere in the south.
                    Rule #1, don't pee on the electric fence!
                    https://www.google.com/search?q=elec...AmhzAS-vsPM%3A
                    T


                    "If Wishes Were Horses, Beggars Would Ride!" Scottish Proverb 1600s
                    Terry

                    Comment


                    • #11
                      Check up on any legal liability issues before you do this. It's one thing to use them for livestock, completely different to use them for security.
                      If there is any way someone could profit from such a "shocking experience", they will find a way to do so. Agree with big_teee that they should not kill people, but they could cause problems for someone in poor health. Tasers aren't supposed to be able to kill either.
                      "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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                      • #12
                        Originally posted by jjj View Post
                        ..."May not ship to Chile"... plus import charges...
                        Another instance where it would be useful to all if you put your location in your profile. That will help people know how best to offer advice.

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                        • #13
                          So, you all reckon that my simple circuit seems to be technically quite safe? I mean, I could reduce the Cap's capacity so, the transformer won't get too much juice. At least the output is isolated from the active AC.
                          As mention, I wished I could somehow verify its strength. Maybe I should look at building a HV meter/tester with with Caps and neon lamp? Something that gives me an estimate of its strength so, I can adjust its power to the lower margin. Any ideas on that?
                          Maybe I should connect a smaller transformer with 220V output? That would at least lower the voltage, for it's only for a short fence of some 4 meters. The moment a thief touches one of the electrified three rows of barbed wire, he will give up and/ or consider ...the the neighbor's fence.

                          Comment


                          • #14
                            Originally posted by jjj View Post
                            Inside my house fence I thought mounting an electric fence barrier, consisting of a super simple circuit. I reckon it should be quite safe or is it?
                            Please have a quick check on it, if there's something lethal. Thank you in advance for your expert advice.
                            Why use an isolation transformer and then short it out by connecting its output back to mains Neutral? What happens if Live and Neutral become reversed? I'd disconnect the bottom of the secondary from Neutral and connect it to Ground.

                            I once made and electric fence energiser using a car ignition coil and a multivibrator. The farmer I made it for decided to test it by touching it and ended up at the other side of the barn. "Hey! Dave it works great!" he said. That was a long time ago. In these more litigious times I think I would just buy what I needed.
                            Last edited by Dave H; 07-29-2015, 04:02 PM.

                            Comment


                            • #15
                              Originally posted by jjj View Post
                              So, you all reckon that my simple circuit seems to be technically quite safe?
                              NO, we are ALL telling you that your idea is UNSAFE .

                              It may easily land you in jail.

                              There must be a reason that NO electric fence uses line frequency power at any voltage, and ALL use ultra narrow ultra low current very high current pulses.

                              Any electric fence installed in Chile must be Government certified and follow :
                              http://www.sec.cl/pls/portal/docs/PA...icas/anexo.pdf

                              which by the way is the Chilean translation of International IEC 60335:
                              http://www.sec.cl/pls/portal/docs/PA...s/NSEG2_76.pdf

                              if anybody from outside can touch your fence you'd better get a commercial, certified one and keep the certificate of compliance handy or you'll be in big trouble.

                              FWIW I live in Argentina, very similar Law as in Chile, we both accept IEC rules.

                              In July last year some workers were repairing my external home wall, from a neighbour's home, and commented me that they felt some "tingling" when touching the wall; commented same thing to the street corner cop.

                              Next morning (7 am) 5 cops in 2 patrol cars knocked my neighbour's door and strip searched his home until they found a homemade device very similar to what you want to use.
                              Looks like a small girl had also complained about "tingling walls" when playing in front of his door but so far nobody had taken her seriously.

                              He is being legally prosecuted today and in BIG trouble.

                              Worst thing for me is that since "my" workmen talked to te Police, now he does not allow them in and the job is still unfinished.

                              Oh well.

                              A few certified Chilean suppliers:
                              CERCO-ELECTRICO.CL Empresa Lider En Cercos Electricos
                              Cercos Eléctricos
                              Protección Extrema | Cercos Eléctricos
                              Cerco Electrico - MercadoLibre Chile
                              this one shows all certifications:
                              :::FIRST SECURITY:::
                              • ¿Es Legal el Cerco Eléctrico en Chile? Si, nuestro Cerco Eléctrico está fabricado bajo la norma internacional ISO 9001-2000, la cual está autorizada por la Superintendencia de Electricidad y Combustibles (SEC), para ser comercializada en nuestro país. Además contamos con los certificados de aprobación y homologación del producto por Departamento de Ingeniería Eléctrica de la Universidad Católica Nº 0131-11-RM
                              EDIT: SEC Chile


                              (the Government Dept involved in this), requires that your Electrical Fence is:
                              * Installed by a Certified Electrician
                              * you fill the licence requirement form (and have it approved, of course)
                              * you supply an installation plan
                              * the fence must be at a certain height and/or have a barrier so nobody can touch it by accident (thieves are exempted )
                              * carry approppriate warning signals
                              http://sec.custhelp.com/app/answers/...NBR0FzbQ%3D%3D
                              Last edited by J M Fahey; 07-29-2015, 04:32 PM.
                              Juan Manuel Fahey

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