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An electrical troubleshooting question regarding my camping trailer. Thoughts?

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  • An electrical troubleshooting question regarding my camping trailer. Thoughts?

    Hello everyone. Last year while camping I came across an issue with my camping trailer that resulted in me receiving a very small electrical shock. I will try to explain and hopefully some of you can possibly help me out.

    -Trailer is plugged into the parks electrical service.
    -everything working fine

    During the evening as the ground and grassy area in front of my trailer entrance became damp I stepped up to trailer to enter in my bare feet in the grass. As I put my hand on the aluminum frame of the entrance i received a small jolt. When I say small I mean I wasn't even sure if it was an electrical shock and so I touched the frame again and sure enough received the shock again. It was so minor that it almost felt like static or something. Here is what I was able to determine.

    -When I received the shock I was standing in BARE feet on damp ground and the light in trailer was ON.
    -Standing in BARE feet on damp ground with light in trailer OFF= NO SHOCK
    -Standing on damp ground with shoes on with light on or off = NO SHOCK
    -Standing in trailer with bare feet or shoes and with light on or off=NO SHOCK

    Trailer was hooked up to 120v.

    The issue is obviously something to do with the light and specifically when it is turned on. In my mind I think I am acting as some sort of ground when standing in bare feet on damp ground.

    The trailer is an old lionel lpl110 from 1972. I bought it from my uncle who only used it for one week a year and then stored it in his garage. They had no kids so it has been very well taken care of. Basically when it is opened up it is pretty much perfect and the canvas were replaced about 10 years ago so they are in fantastic shape as well. Being that it is quite old I am not going to get to fancy with it and try to rewire or something like that but I would like to try and fix this issue if fairly reasonable.

    Thanks for reading and I appreciate you offering your knowledge.
    sigpicSPCHT

    Proud member since Oct '06

  • #2

    Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

    Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

    more than likly that is only 12 volt exterior light try puting a ground from the hitch to the earth small wire and rod into the earth try on pavement to see if you still get shock, use a volt meter from trailer hitch to the damp earth to see if you get a reading ,maybe the safty chain from the tongue to ground will do it ,check ground wiring from the inverter charge to the frame

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    • #3

      Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

      Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

      Is it a three wire circuit? Is the ground connected to the frame? Are you using an adapter to defeat the grounding?

      I presume that the AC is wired throughout the trailer and that the light you are turning on is indeed AC -- or is the AC for recharging (floating) a battery?

      As stated -- you can hook it up at home and test for the presence of AC between the frame and the earth if you have a decent voltmeter.

      If you detect a voltage then you can use the Ohmeter portion to look for the connection between the hot lead (black/small) and the frame from your sockets inside. With the AC input disconnected of course...
      ---
      Will

      “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” —- Mark Twain

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      • #4

        Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

        Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

        In older trailers it was common for exterior lights to be grounded to the aluminum shell. If you could connect a good ground from the shell to the trailer frame this may do the trick and save having to run a ground from the light to the frame.

        Bill R

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        • #5

          Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

          Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

          Yes, you were acting as a ground and it very likely means that the ground for the trailer (the third pin on the plug) is open or the outlet it was plugged into had no working ground or you used, as mentioned above, a 2 pin to 3 pin cheater.

          What makes slightly less sense to me is how the inverter comes into the equation assuming the lights are 12V and only run off 120V via the inverter. 12V should not give you a shock.

          You didn't mention how bad the shock was, if it was just a bit of a tingle you may just have some insulation leakage. If the trailer was grounded you wouldn't notice it because the trailer frame should be grounded. I have an old refrigerator that I would get a tingle from if I touched it and the stove. I measured about 50V between it and the grounded stove. (With an analog meter, reducing the voltage range will cause the apparent voltage to drop because the impedence of the meter is reduced, this won't work with a digital meter.) The refrigerator only had a 2 pin plug so addng a ground wire fixed the problem and that was 40 years ago.

          If the light is 12V powered by the inverter then it seems the inverter is only powered up if a light/load is turned on.

          Check the ground first. If there is a hard short from the inverter to the frame and you fix the ground it will likely blow the fuse or something!!! This makes me wonder if maybe there is a short and it blew open the ground wire/connection at some point.

          The worst shock I ever got was standing on a basement floor in my socks and touching a 120V source. be careful.

          billh

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          • #6

            Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

            Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

            Personally I would get a licenced electrican to check it out...A minor shock could develope into something serious!!!!! Looks like a ground problem...An electrican will "megger" the grd circuit...J
            Don't do anything that you're not prepared to explain to a paramedic

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            • #7

              Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

              Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

              Hey guys,

              Thanks for your input. Jim, I actually already have contacted a friend / contractor that I know and he has agrred to come over tomorrow and check it out at noon. There was a lot of thoughts in the posts above which led me to believ that it may not be that simple to determine.

              I will post an update tomorrow evening. Like I said. I am not going to get alll that fancy with it because I can just run an extension cord from the camground power source and bring a lamp instead for lighting.

              Kevin
              sigpicSPCHT

              Proud member since Oct '06

              Comment


              • #8

                Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                Good idea. I had a 73 model Starcraft pop up. The only things in there that were110volts was the receptacles. The lights were 12 volt thru an inverter. I could see you having a leakage from your 110 circuit after in ran thru inverter to the receptacles. 12 volt won't even give you a tingle. The 110 volt line on my trailer came out of inverter to the exposed underside of trailer and ran thru holes in the steel frame. If yours is similar, there could be abrasion at one of those holes. 40 years of aging will make wiring coverings brittle.
                Discussion is the mother or father of ideas.
                Discord is the bastard son of discussion.


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                • #9

                  Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                  Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                  Well here is the update. Met with electrician and it turns out that the problem was caused by the campground power source. My electrican confirmed that everything was grounding properly and said that it had to be coming from the source of power i was using which obviously was at the campground.

                  Question though if someone hopefully doesn't mind explaining for me. First of all, can someone please explain this to me in an easy to understand way and why would it be sending a small shock when the light only when the light was on and not off?

                  Thanks for your help
                  sigpicSPCHT

                  Proud member since Oct '06

                  Comment


                  • #10

                    Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                    Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                    Originally posted by Kevin in Keswick View Post
                    Well here is the update. Met with electrician and it turns out that the problem was caused by the campground power source. My electrican confirmed that everything was grounding properly and said that it had to be coming from the source of power i was using which obviously was at the campground.

                    Question though if someone hopefully doesn't mind explaining for me. First of all, can someone please explain this to me in an easy to understand way and why would it be sending a small shock when the light only when the light was on and not off?

                    Thanks for your help
                    A faulty ground is the most likely. But who knows????

                    Buy a circuit tester that lights up to show if plug wiring is faulty and test before you use campground power.
                    http://en.wikipedia.org/wiki/Receptacle_tester

                    There are many types.
                    http://www.myrv.us/electric/Pg/testing.htm

                    It could be worth your life...
                    ---
                    Will

                    “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” —- Mark Twain

                    Comment


                    • #11

                      Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                      Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                      Originally posted by Kevin in Keswick View Post
                      Well here is the update. Met with electrician and it turns out that the problem was caused by the campground power source. My electrican confirmed that everything was grounding properly and said that it had to be coming from the source of power i was using which obviously was at the campground.

                      Question though if someone hopefully doesn't mind explaining for me. First of all, can someone please explain this to me in an easy to understand way and why would it be sending a small shock when the light only when the light was on and not off?

                      Thanks for your help
                      Hi, all electrical devices have a very small amount of current that "leaks" to ground either through the insulation or capacitive coupling.

                      If your trailer isn't properly grounded, this small leakage current will flow through you to ground if you're not wearing a good set of foot wear.

                      In a properly grounded system this current will flow to ground via the ground conductor.

                      The current will be small, maybe 5 to 10 milli-amperes ( a 60 watt lamp would use 500 milli-amperes).

                      If the current exceeds about 75 to 100 milli-amperes, ventricular fibrilation will take place.

                      At about 10 to 15 milli-amperes your muscles cannot release and you will not be able to let go of the trailer door handle.

                      At this point the amount of current that would run acouple night lights has resulted in a fatality................Grounding is the only wire in the electrical system that has to work perfectly............Rod.
                      Last edited by Rod Sheridan; 04-15-2012, 06:44 PM.
                      Work is the curse of the riding class.

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                      • #12

                        Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                        Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                        I don't know if this would work but I'd wire in a GFCI just after the trailer to park plug in , that way everything "downstream" should be protected.

                        Comment


                        • #13

                          Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                          Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                          Originally posted by Pete in Milton View Post
                          I don't know if this would work but I'd wire in a GFCI just after the trailer to park plug in , that way everything "downstream" should be protected.
                          It certainly would work -- unless it were a defective ground or mis-wiring of hot and neutral -- and that would be likely for what is described. He has to deal with the problem "at source". After he checks that the camp wiring is correct -- then a ground to the trailer should suffice -- although a GFCI would be nice insurance. So the GFCI will only do it's job if the wiring is correct to begin with.
                          ---
                          Will

                          “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” —- Mark Twain

                          Comment


                          • #14

                            Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                            Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                            Would a polarity check light at the trailer input help? Check that for reverse polarity before switching on 120V in the trailer?

                            Comment


                            • #15

                              Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                              Re: An electrical troubleshooting question regarding my camping trailer. Thoughts?

                              Originally posted by willr View Post
                              It certainly would work -- unless it were a defective ground or mis-wiring of hot and neutral -- and that would be likely for what is described. He has to deal with the problem "at source". After he checks that the camp wiring is correct -- then a ground to the trailer should suffice -- although a GFCI would be nice insurance. So the GFCI will only do it's job if the wiring is correct to begin with.
                              WILLR, it is interesting that you said what you did about the reverse polarity. My electrican did confirm that one (only one) of the 4 receptacles inside the trailer has reverse polarity and I am going to fix that when I get a chance over the next few days. This receptacle was not in use when the shock happened. I also suggested that I pick up a GFCI Power Bar to him and he said that would be fine but that it may cause problems if the supply from the campground that I am using is a GFCI itself.

                              Would this be the case and would a gfci power bar have solved the original shock incident that began this thread?

                              I am sorry for the questions but I REALLY APPRECIATE the help.
                              Last edited by Kevin in Keswick; 04-16-2012, 07:51 PM.
                              sigpicSPCHT

                              Proud member since Oct '06

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