oakback
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Post by oakback on Aug 15, 2019 5:09:47 GMT -8
I had an experience with a 15A service with a bad ground, which caused a hot skin scenario. At first I suspected a short somewhere, but an outlet tester and switching power sources proved it was a bad ground.
Is there something I can do do prevent this from shocking someone, if it were to happen again? I'd hate to have my kid grab the door with a hot skin on 30A service.
My 110v and 12v systems are both grounded to the frame. I don't have an intentional frame-to-skin ground (but they do touch in many places), but would that have made a difference? Should I ground the frame to the actual ground/earth/dirt with an metal stake or something like that, when parked and powered?
My thought is that the tires insulate the whole thing from the ground/earth/dirt, and someone grabbing the doorknob becomes the path of least resistance (when the shore power has a bad ground), correct me if I'm wrong.
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kirkadie
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Post by kirkadie on Aug 15, 2019 8:33:07 GMT -8
Don't know if anyone has tried this, but back in the 50s and 60s lots of cars had flexible grounding straps attached somewhere on the frame, and hung down far enough to have contact with the road surface. If I remember correctly the contact end of the strap had a metal end, kind of like a military style woven belt. I think the grounding straps main purpose was to prevent static shock created by certain fabric seat covers, but seems to me those straps might do the same for your rig. But that was a long time ago and memories can deceive..
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Post by danrhodes on Aug 15, 2019 8:53:17 GMT -8
I'm still trying to get my head around how this results in a hot skin if your trailer was wired correctly with neutral and ground separate. Were the neutral and ground tied together in the service box which was not grounded itself?
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oakback
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Post by oakback on Aug 15, 2019 11:25:13 GMT -8
Converter box was wired to manufacturer's specifications, neutral and ground are not tied together. Neutral comes from shore power to converter, to neutral bus bar, where all 110v neutrals terminate. Ground comes from shore power to converter, to ground bus bar, where all 110v grounds terminate, and there's also a wire from the ground bus bar to the frame. All 12v circuit grounds terminate at a ground bus bar, which then also has a wire to the frame for ground. If 110 shore power has no ground, it'll ground where it finds a path, right? At the time happened to be from the doorknob through my wife's hand, through her bare feet to the ground.
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Post by danrhodes on Aug 15, 2019 13:20:33 GMT -8
Converter box was wired to manufacturer's specifications, neutral and ground are not tied together. Neutral comes from shore power to converter, to neutral bus bar, where all 110v neutrals terminate. Ground comes from shore power to converter, to ground bus bar, where all 110v grounds terminate, and there's also a wire from the ground bus bar to the frame. All 12v circuit grounds terminate at a ground bus bar, which then also has a wire to the frame for ground. If 110 shore power has no ground, it'll ground where it finds a path, right? At the time happened to be from the doorknob through my wife's hand, through her bare feet to the ground. I would suspect that your trailer has neutral and ground bonded together incorrectly in one of your devices. This coupled with a reverse wired camp service could result in the hot skin you experienced. The ground should never conduct any AC current in a properly wired trailer, it is there for safety only.
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kirkadie
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Post by kirkadie on Aug 15, 2019 14:43:08 GMT -8
Did this problem happen at home, or a campground? Have you tested your system at any other location with no problem?
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aslmx
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Post by aslmx on Aug 15, 2019 16:06:05 GMT -8
^^^^^ This is what I’m thinking also. Try it on another connection. Sounds like the camp ground lost a bond. Kind of like an old house when you would touch the fridge and stove at the same time and get the crap knocked out of you. Also check your grounds and make sure they are tight. Check your cord and make sure a ground prong hasn’t pulled loose from the plug.
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Post by bigbill on Aug 15, 2019 17:20:29 GMT -8
You can purchase a plug in test unit to test a 15 amp receptacle at a campsite before plugging trailer into it. It will tell you if the receptacle is wired correctly, including the ground. They are less than ten dollars I think.
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kirkadie
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Post by kirkadie on Aug 15, 2019 18:48:38 GMT -8
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mobiltec
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Post by mobiltec on Aug 16, 2019 16:26:32 GMT -8
Normally the 15 or 20 amp household outlet on a RV Park Pedestal has a GFI or GFCI breaker on it. The neutral in this outlet uses the same buss bar in the panel as ground. So the ground is actually hot. You hook your trailer up to that and you just heated up the metal on the trailer... That's if your trailer does not trip the GFI. And if the GFI on the pedestal is non-existent, well first of all the park is out of code. Second you will heat up your metal skin.
DON'T USE THE 15 or 20 AMP OUTLET ON THE PEDESTAL.... USE THE 30 AMP RV plug or the 50 AMP RV plug with an adapter if you are using a regular household type plug to fire up your trailer... Better yet, PUT THE RIGHT RV PLUG ON YOUR TRAILER AND NEVER WORRY ABOUT IT AGAIN!!!!!
Why does everyone keep fighting me on this?
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aslmx
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Post by aslmx on Aug 17, 2019 13:59:19 GMT -8
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mobiltec
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Post by mobiltec on Aug 17, 2019 16:35:15 GMT -8
If that is supposed to be an image I can't see it...
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Post by danrhodes on Aug 17, 2019 19:22:22 GMT -8
DON'T USE THE 15 or 20 AMP OUTLET ON THE PEDESTAL.... USE THE 30 AMP RV plug or the 50 AMP RV plug with an adapter if you are using a regular household type plug to fire up your trailer... Better yet, PUT THE RIGHT RV PLUG ON YOUR TRAILER AND NEVER WORRY ABOUT IT AGAIN!!!!! Why does everyone keep fighting me on this? Not fighting... Didn't really know this. Just bought a 30a to 15a adapter so now I know to use this always.
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aslmx
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Post by aslmx on Aug 21, 2019 13:49:53 GMT -8
If that is supposed to be an image I can't see it... I can’t remember what it was. Must had been an ambien moment.
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oakback
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Post by oakback on Aug 23, 2019 4:59:25 GMT -8
Did this problem happen at home, or a campground? Have you tested your system at any other location with no problem? This was at home, with an extension cord with a faulty ground prong. I tried it in a different outlet (GFCI, rewly replaced), which I successfully tested with an outlet tester exactly like the one you linked to, and it worked fine. It was definitely a faulty ground at the power source (via the bad extension cord). I just camped at 2 different campgrounds with 30A service with no problems. I'm just trying to avoid shocks in the future if there's a faulty ground at the power source, now that I know this is possible. Normally the 15 or 20 amp household outlet on a RV Park Pedestal has a GFI or GFCI breaker on it. The neutral in this outlet uses the same buss bar in the panel as ground. So the ground is actually hot. You hook your trailer up to that and you just heated up the metal on the trailer... That's if your trailer does not trip the GFI. And if the GFI on the pedestal is non-existent, well first of all the park is out of code. Second you will heat up your metal skin. DON'T USE THE 15 or 20 AMP OUTLET ON THE PEDESTAL.... USE THE 30 AMP RV plug or the 50 AMP RV plug with an adapter if you are using a regular household type plug to fire up your trailer... Better yet, PUT THE RIGHT RV PLUG ON YOUR TRAILER AND NEVER WORRY ABOUT IT AGAIN!!!!! Why does everyone keep fighting me on this? It was a 15A household outlet, faulty ground on extension cord, no GFCI. I was in the process of replacing a GFCI outlet on my house that I normally use for my camper when at home. So far, at campgrounds I've only used 30A pedestals with a proper 30A plug, no adapters. I use an adapter when plugged at home to 15A. Normally at home it's always plugged into a GFCI outlet to power a dehumidifier. I hope I've answered remaining questions as to the cause. What I'm not wondering is, theoretically, if a campground pedestal has a bad ground for whatever reason, what can I do to keep people from getting zapped when touching the camper? Or do 30A pedestals typically have a GFCI function that I can see or test?
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