wanderso Posted May 25, 2011 Share Posted May 25, 2011 On the "new to me" 91 Winnebago Warrior, I've noticed a 12v electrical charge on the metal of the vehicle chassis (hood, fender well, etc.). I anticipate that there is obviously an electrical short somewhere that is actually touching the chassis which is quite alarming actually because it could result in an electrical fire (worst case) or in a lessor case a dead battery. I know that it is coming from the Toyota chassis and not the coach battery as the problem does not go away when I remove the coach battery connections. Any suggestions on where I should start the investigation? Starter? Isolation block? Or? Anyone else encounter this issue? The battery isn't hooked up backwards (of course) so it isn't something as obvious as that and preliminary visual inspections haven't thus far revealed the culprit. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted May 25, 2011 Share Posted May 25, 2011 I suppose that pulling the fuses from the Toyota fuse block one by one would help you isolate which circuit is responsible. I hate electrical problems! Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 25, 2011 Share Posted May 25, 2011 I have got to ask how have you measured this? Quote Link to comment Share on other sites More sharing options...
waiter Posted May 26, 2011 Share Posted May 26, 2011 You have 12 volts on the chassis, compared to what? Where are you putting the meter probes when you measure this?? John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 26, 2011 Author Share Posted May 26, 2011 You have 12 volts on the chassis, compared to what? Where are you putting the meter probes when you measure this?? John Mc 88 Dolphin 4 Auto Great questions. In this case, I haven't yet put my volt meter to test it. (working for a living gets in the way of my "fun" time...) In this case, interestingly it literally is a "shock" felt when touching exposed metal, such as a chip in the paint or on the RV frame. This is what makes it unlikely that it is just 12 volts that I am feeling as the natural ohms resistance of the human body would make a 12 volt charge largely not noticeable. Ever stuck your tongue on a 9-volt battery as a kid to feel that it is "charged"? That is about what the feeling is to the finger's touch. It certainly does not feel like standard 110/120v household current which I have felt before (not on purpose of course). In talking to an electrician, he thinks that the voltage I am feeling is likely much higher than 12 volts, especially when you consider I am feeling this shock due to the circuit being completed between my feet (on the ground) and touching the RV. A few thoughts might be a capacitor in the RV electronics or vehicle that is not properly discharging and is grounded against the body. Perhaps a malfunctioning engine coil? All are simple guesses that I will have to explore through the process of elimination. The best way that I figure I would have to measure it is to drive a ground stake and touch the volt meter between the stake and the RV chassis. It's obviously something that I have to figure out, especially when one considers that RVs carry around propane and such. I know that this seems kind of like folklore and I've not experienced it on any vehicle (have had dead shorts in the past which were different), but it genuinely is an issue that I need to solve. The NIOSH states "Under dry conditions, the resistance offered by the human body may be as high as 100,000 Ohms. Wet or broken skin may drop the body's resistance to 1,000 Ohms," adding that "high-voltage electrical energy quickly breaks down human skin, reducing the human body's resistance to 500 Ohms." Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 26, 2011 Author Share Posted May 26, 2011 Oh - and this isn't just static electricity. Quote Link to comment Share on other sites More sharing options...
troyrobo Posted May 26, 2011 Share Posted May 26, 2011 Are you plugged into shore power when you feel this? if you are-- then it might be from a open groud circut you are plugged into. i had this happen to me before. Quote Link to comment Share on other sites More sharing options...
WME Posted May 26, 2011 Share Posted May 26, 2011 I think Troyrobo has the right idea, you have an ungrounded or reverse wired AC line. The frame is supposed to be hooked to the ground lead not the neutral lead. Head to ACE and get a AC polarity checker for a few bucks and check the rv AND your house plug. Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 26, 2011 Share Posted May 26, 2011 If this is doing it only plugged in unplug it right now! There are many things that can be wrong as WRE said inverted wires, poor or no ground, grounded neutral wire, improperly wired breaker box, bad inverter, what ever the cause it is dangerous perhaps even worse. Unlike your home the neutral wire is not grounded it is isolated the ideal behind that is for improper wiring at campgrounds and ending up with a hot frame (truck) the ground should take care of that and trip the breaker provided the grounding is good and it's never good to guess that it is. The best thing to do is check between a known good house ground and your frame with an AC meter DO NOT touch your frame work while you do this and if it reads any thing unplug it and find out why. WRE suggested a 3 lamp tester I never leave home with out one I don't trust campground wiring. Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 28, 2011 Author Share Posted May 28, 2011 Excellent tips about shore power. Thanks. The "stumper" here is that this is happening when I am not connected to shore power. Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 28, 2011 Author Share Posted May 28, 2011 Excellent tips about shore power. Thanks. The "stumper" here is that this is happening when I am not connected to shore power. Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 28, 2011 Author Share Posted May 28, 2011 Of course that doesn't mean that there might be an AC item still causing the issue (mircowave?). I'll do some more tests. Quote Link to comment Share on other sites More sharing options...
wanderso Posted May 29, 2011 Author Share Posted May 29, 2011 Ok - so I have the answer. The storage location I am at has high voltage transmission lines that go overhead of the facility. These are creating a static charge in the air that transmits onto the body of the RV. If move it to a different location, the problem goes away. If I return, the problem always comes back. Placing a volt meter on the metal causes an erratic reading of 100+ volts in this location. I found that another RV nearby exhibits the same issue, but to a much lesser degree. Perhaps the combo of metal roof and fiberglass sides on the rig makes it much worse than the other rig. Quote Link to comment Share on other sites More sharing options...
Vanman Posted May 29, 2011 Share Posted May 29, 2011 <br />Ok - so I have the answer. The storage location I am at has high voltage transmission lines that go overhead of the facility. These are creating a static charge in the air that transmits onto the body of the RV. If move it to a different location, the problem goes away. If I return, the problem always comes back. Placing a volt meter on the metal causes an erratic reading of 100+ volts in this location. I found that another RV nearby exhibits the same issue, but to a much lesser degree. Perhaps the combo of metal roof and fiberglass sides on the rig makes it much worse than the other rig. A test for static would be to put a grounding strap on the RV and see if the problem is solved, caution here is this sounds like it might be something I read about and also saw on TV where the utility has a grounding problem, in which case the grounding strap might make it worse. vanman Quote Link to comment Share on other sites More sharing options...
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