AC Voltage Through Frame/Stablizers

[mbrooks43]

Today I was adjusting my stabilizers and got a small, constant shock. I got out my multi-meter and began to seek the issue. I was getting jolts of 5volts (DC) but nothing steady. I checked AC current and was getting 140v (AC). I got this on several stabilizers and even 80-90v on the front of the frame.

Any idea what is causing this?

[vermilye]

As CA Traveler noted, you have solved the source of the problem, however you still need to fix the grounding problem.

When you have a fault to ground, a low current one will be carried through the ground system, preventing or reducing the chance of a shock between the frame of the vehicle & the earth. With a proper ground and a low resistance fault (such as a short between the hot wire & the clamp in your case), the high current should have tripped the circuit breaker for that circuit. Since it didn't, your trailer ground system is faulty. Could be the power cable, an adapter, or the power pedestal, but unless you identify the problem & fix it, you are leaving yourself open to a shock hazard in the future.

[therink]

That happened to me once and found out it was caused by high voltage overhead power lines that went through an easement at the campground I as staying at. Had voltage readings between 5-8 volts AC. Same with the other family we were camping with. I had 0 volts when I got home. I thought I had a polarity or ground issue. Was very pleased to find out I didn't. Definitely ruined that camping trip.

[westend]

So, the issue appears to have been a hot wire conducting through the load center entry clamp. then shorting power to the load center chassis which is grounded to the frame.
This still doesn't entirely disclose why the shorted power was not carried through the RV frame and to the house's load center. We're dealing with leakage current amounts, here, and varying ground potentials but if the ground plane of the RV is continuous to the house's load center ground and there was significant current through the bad wire, it should have grounded to the source load center and not the stabilizer jacks.

I'd still suggest to use your meter to make sure you have a good ground path. Measure resistance between ground points.

[CA_Traveler]

Good to solve that problem. Use the three light tester to verify that the wiring in the rig is correct. Get one with a GFCI test button. Leave it plugged in. I've found 2 CG sites with reverse polarity. From your description you'll find a open ground which can be dangerous and must be fixed - not should but must.

Next plug the rig with adapter into a standard household GFCI. Turn appliances on and off to verify everything OK. Push the tester button to verify that the GFCI is working.

Then your done!

[mbrooks43]

I went through the AC unit and tested a few things and believe the issue is within the wire, not the unit. I returned to the breaker box and did not see anything obvious. But, it did appear the clamp which holds the wire into the box was on quite tight, pressing into the wire. It did not appear damaged but clearly squished. I cut the foot of wire off and re-wired it and seems to have solved the issue. There is still no obvious damage to the wire, but no more voltage issues, but I will keep an eye on it.

Thanks all!

[time2roll]

mbrooks43 wrote:

CA Traveler wrote:
The ground should not have power but it is a safety wire in case you have a ground fault. Something is leaking current to ground. In addition you have a bad ground.

Several have advised you to check with the 3 light tester and to plug into a GFCI circuit which is a good idea.

A very small leakage to ground (under 5ma) is acceptable but above that a GFCI will trip.

I understand something is leaking current. But, when I shut off the AC breaker, I have no issue. Is it possible it is still a different circuit?

All of my problems go away once the AC breaker is turned off. No more power anywhere I do not want it.

I assume you have reviewed the air conditioner hot wire off the breaker has insulation attached into the romex cover there at the breaker.

Next go up in the air conditioner and open the J-box for inpection.

Then disconnect the Hot, neutral, ground and see if the fault still exists. If that cures the issue it is probably in the air conditioner. If the issue persists it is probably in the romex.

You need to pull stuff apart to isolate the issue.

Be safe about it.

[BB_TX]

If you have proper connection of the ground wire from the outlet all the way to the trailer frame you will not have voltage at all on the frame. If you have a short if will trip a breaker. If it is induced voltage it will be dissipated without you feeling it.
Turning off the breaker is eliminating the source of the stray voltage. The stray voltage could be a short. Or it could be voltage induced into the surrounding metal due to the energy field created due to the current flow.
In any event the first thing to do is ensure you have good solid connection of ground from the source (outlet) to the frame.

[Gdetrailer]

mbrooks43 wrote:
I keep getting more and more confused. Either I have a flawed understanding of AC current and/or something is messed up.

I have unhooked all the grounds from the block. When I turn the AC breaker on which is #2 after the main breaker, all the grounds now appear hot (other than incoming power)when connected to the white wire block. The white wire and ground each have a block and the black wires go through the breakers. With the breaker off, I get no power between white and the grounds. With this breaker on (all others are fine) I get power between the white and the grounds.

My thought was the white and black should have power, not the grounds....but, maybe I am wrong.

I cant imagine how, but could the breaker be the problem?

It isn't the A/C breaker but the A/C it's self OR perhaps the wiring to the A/C) which has some sort of leakage from HOT to ground AND you may have a OPEN ground connection from your shore cord to your home breaker box or worse the service entrance grounding rods are not functioning.

In your home MAIN breaker panel the equipment ground AND the neutral wires should be connected together (IE BONDED). The ground buss on the main breaker panel will be connected to a ground rod (older setups allowed for only one ground rod but newer systems most likely will have two ground rods)

Anyway you cut it, your EQUIPMENT GROUND IS OPEN, you need to verify at your home outlets that there is NO VOLTAGE present on the ground or neutral wires with and without your trailer attached and the A/C breaker on.

Your A/C, you might want to remove the inside cover and check the wiring in there to make sure the wires were not reversed or damaged when put in. You could disconnect the wires at the A/C unit and verify that there is no shorts on the wire run.

[mbrooks43]

CA Traveler wrote:
The ground should not have power but it is a safety wire in case you have a ground fault. Something is leaking current to ground. In addition you have a bad ground.

Several have advised you to check with the 3 light tester and to plug into a GFCI circuit which is a good idea.

A very small leakage to ground (under 5ma) is acceptable but above that a GFCI will trip.

I understand something is leaking current. But, when I shut off the AC breaker, I have no issue. Is it possible it is still a different circuit?

All of my problems go away once the AC breaker is turned off. No more power anywhere I do not want it.

[CA_Traveler]

mbrooks43 wrote:
I am hooked up at my house at 30amps. I have verified the cable is correct as well as the incoming cable from trailer side to breaker box is not an issue. The issue lies within the wiring surrounding the AC and its breaker.

Maybe. But 80V from the frame to ground means you have a bad ground wire. It could be the rig or the 30A plug.

[westend]

You're basically trying to diagnose this from the wrong end of the problem. Instead of finding the electrical path of any power, first, establish ground continuity.
Here's the rules: Your RV grounding system should have a ground continuous to the frame from the load center. That ground should not be connected to neutral in the RV load center or anywhere else in the RV. The ground path should be continuous from the trailer load center and frame, through the shore cord, and to the receptacle that delivers power, then continuous to the ground of the load center, either on a pedestal or in a house.

As smkettner says, with the AC leaking current, you've found half the problem. The other half is to have an uninterrupted ground from the RV devices to the power source, the pedestal or the load center in your house. Every receptacle and device in the RV should show continuity to ground and you should be able to measure power from hot to ground when the devices are powered.

[CA_Traveler]

The ground should not have power but it is a safety wire in case you have a ground fault. Something is leaking current to ground. In addition you have a bad ground.

Several have advised you to check with the 3 light tester and to plug into a GFCI circuit which is a good idea.

A very small leakage to ground (under 5ma) is acceptable but above that a GFCI will trip.

[mbrooks43]

I am hooked up at my house at 30amps. I have verified the cable is correct as well as the incoming cable from trailer side to breaker box is not an issue. The issue lies within the wiring surrounding the AC and its breaker.

[RoyB]

Keep in mind the pedestal connection is the only FRAME GROUND you get. Really important to have good cables and use all conductors (three conductor for 30AMP and four conductor for 50AMP service)

Like said above ADAPTERs are usually the culprit. Of course the CAMPGROUND PEDESTALS SERVICE is used everyday and really start going downhill early on from being used so much.

If I see a CAMPGROUND 30AMP Service PEDESTAL looking pretty bad I will use my 50A-30A Long Adapter and plug into the 50AMP side just to get the better contacts...

Also having the circuit tester on hand is must for me as well... I have one plugged into a KILL-A-WATT meter outlet and plug that into the camp ground pedestal before hooking up. I can see the line voltage as well as the correct grounds and polarity lights being lit up on the circuit tester. Just takes a couple of minutes to test.

Roy Ken