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Letsgoagain · 06-19-2015, 08:21 PM

Yesterday while I was greasing the driveshaft u joints and slip yoke I kept thinking that something was sticking me everytime I rested my bare arm on a piece of angle iron that runs between the two rear leveling jacks. Took me a few minutes and touching another bar in front of it to realize it was electric current. Very small tinge from it.
I realize that means some where I have a hot wire that's touching something its not supposed to.

Not sure how to go about trying to find the hot wire or just what the problem is. Could sure use help in how to trouble shoot this.

pwhittle · 06-19-2015, 08:29 PM

Were you plugged in to shore power?

Paul

cb1000rider · 06-19-2015, 08:53 PM

Or is something not well grounded? You can feel a 12v "tinge" especially if you're sweaty.. trust me. To me, it means that there is a better path between you and the "ground"... It could be as simple as a poorly grounded battery.

Let us know if you think it's shore power or 12V power, my diagnostic procedure would be different.

Letsgoagain · 06-19-2015, 09:26 PM

Quote:

Originally Posted by pwhittle

Were you plugged in to shore power?

Paul

Yes I am plugged in at home. I run a heavy duty extension cord from a 15 amp circuit in garage. I started a search on here and came across the issue of a hot skin in the RV101 electrical safety series.. Caused possibly by a bad grounding plug in the supply line either in the extension cord or possibly in garage. Has me concerned enough to go get a non contact tester tomorrow to see if the frame is hot

oldguy70 · 06-19-2015, 09:59 PM

I would have some at the breaker panel open each breaker while you check
the tingle or a volt meter might work when you get to a breaker that the
tingling stops, you have the circuit that has the short. From there you just have to keep looking. I am sure it isn't the 12 volt as working as a mechanic I have never felt a 24 volt system

Arch Hoagland · 06-19-2015, 10:06 PM

Keep us posted on what you find.

ShapeShifter · 06-20-2015, 05:23 AM

Quote:

Originally Posted by Letsgoagain

Caused possibly by a bad grounding plug in the supply line either in the extension cord or possibly in garage. Has me concerned enough to go get a non contact tester tomorrow to see if the frame is hot

An open ground in your shore power path is a very likely cause, and where I would start. Yes, you should be concerned, it is a potential safety issue. A non-contact tester might not be the best tool. Your frame likely isn't hot, at least not full voltage, or else you would feel more than a slight twinge. You likely only have a few volts on the frame, due to inductance or minor leakage, and the non-contact tester may not pick that up.

I would start with one of those little three light circuit testers, they are specifically designed to detect open ground. Plug it into a socket on your coach to confirm the open ground. Then keep plugging it in closer and closer to the socket in your garage. As soon as you see that there is a ground, then the part you just passed (adapter, extension cord, etc) is the one with the problem. I would get one with the GFCI test button on it as shown: it's not much more than the basic version, and is useful for testing outlets downstream of a GFCI outlet.

Once you get this fixed, you should seriously consider the protection that a Progressive Industries EMS/Surge protector offers. One of the many electrical tests it does automatically is check for open ground, and it won't let power pass. An open ground is serious: it can range from having no effect, to a minor twinge, a nasty jolt, or a lethal shock.

Letsgoagain · 07-02-2015, 09:40 PM

Evening,

Been camping and busy with every day life but I wanted to post a follow up to what I think may have been the original problem.
I drove a copper pipe in the ground about three feet close behind the motorhome and took a volt meter and checked if there was any current coming off the frame by touching the frame and grounding pole with the volt meters probes. Made sure I had god contact with bare metal. I didn't get any readings.
Implausible as this seems I think the problem was I had moved the motorhome forward a few feet to get the drive shaft zerk fittings more accessible and inadvertently ran the right front tire on the extension cord I was using to power my pancake air compressor. I hadn't noticed that until I went out there later to put my tools up. Wow that cord was squashed flat between the board I park on and tire. I think it must have pinched it enough to allow some current to flow either to the frame or down the air line to the metal grease gun I was using. I think whenever I touched the frame I was the ground.
I have a surgeguard but don't use it at home because I only have a 15 amp circuit to the motorhome. I think I will do two things as ShapeShifter suggested. Start using the Surge Guard at home if it will work on 15 amps and get one of the three light circuit testers.
Thanks for replies and suggestions.

Arch Hoagland · 07-03-2015, 12:25 AM

Thanks for the update...glad you found out what was causing the problem.

ShapeShifter · 07-03-2015, 06:06 AM

Quote:

Originally Posted by Letsgoagain

Implausible as this seems I think the problem was I had moved the motorhome forward a few feet to get the drive shaft zerk fittings more accessible and inadvertently ran the right front tire on the extension cord I was using to power my pancake air compressor. I hadn't noticed that until I went out there later to put my tools up. Wow that cord was squashed flat between the board I park on and tire. I think it must have pinched it enough to allow some current to flow either to the frame or down the air line to the metal grease gun I was using. I think whenever I touched the frame I was the ground.

Yes, it sounds very implausible. I simply don't see it happening unless the cord was squashed to the point that the ground line broke, AND another conductor got exposed, AND that other conductor shorted to the compressor's side of the broken ground wire, AND your air hose is either metal or has metal braid reinforcement. With your coach simply parked on the extension cord, and with a rubber or plastic air hose, I simply don't see how you could've had a path that allows current to flow. And if there were a path, you would only feel it if the tool wasn't touching the frame, but you had it in one hand and touched the frame with the other, completing the circuit and allowing current to flow. If the compressor were plugged into a GFCI, that should've been enough to trip it. If the tool were touching the frame, and the shore cord ground were good, the hot tool wouldn't be energizing the frame, power would just be running down the frame to ground (and once again tripping a GFCI on the compressor power feed if one is there.)

A much more likely scenario is that you have a loose or intermittent ground connection, and by the time you went to do your ground rod testing you had bumped or moved the connection enough that it is now making a connection. Even if it's now making a connection, you haven't fixed anything and it WILL happen again. Tracking down an intermittent connection is the bane of any technician.

You say you're plugged into 15 amps at home. The problem could be in the socket you're using, in the adapter, an extension cord, your shore cord, etc. One way to track it down is to hook up your meter to the ground rod as you did, and have one person watch it while another person moves, twists, and flexes every part of the electrical connections. If the meter jumps at any time while doing that, you've found the suspicious location.

Quote:

I have a surgeguard but don't use it at home because I only have a 15 amp circuit to the motorhome. I think I will do two things as ShapeShifter suggested. Start using the Surge Guard at home if it will work on 15 amps and get one of the three light circuit testers.

That's a good idea. You bought that for electrical protection. You probably spend more time plugged in at home than you spend on the road. It doesn't make sense to forgo that protection a majority of the time, does it? It will work just as well with an adapter on 15 amp power as it will on full shore power.

Is your SurgeGuard one of the more advanced units that specifically looks for wiring problems like an open ground? Or is it one of the entry level units that is surge only with no other fault protection? If it isn't one of the full featured units, I think you should consider upgrading.

Letsgoagain · 07-03-2015, 09:56 AM

ShapeShifter,

First of all, thank you for in depth reply. Upon reading it I decided to investigate further and also put my surge guard in place.
Well guess what. I hooked it up, let it cycle its 128 seconds and then checked the readings. No faults. I then hooked the motorhome 50 amp power cord to the surge guard and immediately got a no ground reverse polarity message on the message screen.
Not sure if that is just a category when it detects a incorrect condition and flashed both no ground and reverse polarity or if those are actually two separate conditions that its detecting. I will research that.
I unplugged and starting checking every inch of the 100 feet of extension cord for any cracks, cuts or breaks in it. Didn't find any so I started looking at the plugs themselves. Nothing obvious. Then it hit me.

I'm plugged into a receptacle that is in the ceiling of my garage. For some reason there are two receptacles in the ceiling that the garage doors are plugged into that only have the old two prong openings and no third grounding prong hole. I'm guessing that is why the no ground fault is showing up on my surge protector.
I moved the extension cord and plugged it into a wall receptacle that does have the third grounding plug hole. Let the surge guard do its checks and then plugged up the motorhome cord without any faults this time.
Not completely satisfied this was it yet. I was twisting and turning the cord thinking perhaps there is something loose or broken in the extension cord but couldn't get it to fail.
Scary part is I've been using that plug for years now and never noticed anything. Still trying to figure out why the two ceiling receptacles are the old type plugs. Every other plug in the house and garage does have the third grounding hole. Going to have to correct the two old ones but hope it doesn't mean running new wires all the way back to the fuse box.
Thanks again. Your explanation of the implausibility of the smashed extension cord caused me to check further.

ShapeShifter · 07-03-2015, 02:16 PM

Quote:

Originally Posted by Letsgoagain

Not sure if that is just a category when it detects a incorrect condition and flashed both no ground and reverse polarity or if those are actually two separate conditions that its detecting. I will research that.

It's tough to say whether the reverse polarity is an artifact of the no ground condition, or if it is a separate problem. Normally, there should be voltage between the hot and neutral lines, and the hot and ground lines, but not the neutral and ground lines. If there is power between neutral and ground, and/or not between hot and ground, that would indicate reverse polarity. But that's all assuming that the ground connection is there. Without a ground connection as a reference, it's tough to detect a reverse polarity situation, and what you get will depend on the way the device implements the reverse polarity test. Furthermore, if the open ground was creating a voltage on the chassis (the twinge you felt) then that would also be present on the ground line sensed by the protection device, and could cause an incorrect fault condition.

If there is a reverse polarity situation, it's likely to be in that two prong socket. Does it have one slot wider than the other? If so, does your extension cord have one prong wider than the other? If either of these is no (which would often be the case with a three prong cord that has the ground prong cut off) it could be that you were plugged into the outlet backwards, and that is causing reverse polarity.

I would do as you say and put proper three prong sockets in the garage ceiling. Hopefully all of the required wires are there and the ground wires simply weren't hooked up to the two prong outlet. If there is no ground wire, you may need to run new wires, or you may be able to just run a ground wire: you should consult a licensed electrician or your local building inspector to tell you the best way to handle it. You can ask on a forum like this, but none of us can see the actual wiring conditions, and probably don't know your local electrical codes. It's best to have a knowledgeable person actually lay eyes on what you have and make the proper recommendation.