Odd electrical motorhome ground leakage

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Old 07-09-16, 09:31 AM
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Odd electrical motorhome ground leakage

'm working on my Toyota motorhome frame/hitch and keep hitting something sharp, I look and nothing, then another funny feeling. Hmmm is that electric? So I get the multimeter and because it is so minor I check DC and nothing zero, I switch over to 200 V AC and it shows 53.5 volts between motor home frame and house ground rod, which is right by me.

This week I put in new electrical service and a new 20A plug buy the window to plug the RV into, did I wire it wrong, not me, well maybe it was late in the day, I was hot and tired, but I know I tested it or did I?

so I turn off roof air unplug and check polarity with the 3 light tester and it shows it is done right. Then I check the extension cord and it checks ok. I test all the outlets in the rv and they all test OK. I check between frame and ground zero, turn on roof air and still zero between frame and ground?

Yes I am sure it was 53.5 volts AC, because it made no sense I checked it several times. The only thing in the RV that might possibly have 53 volts is the Progressive Dynamics PD9145A converter.

Any ideas? I'm not sure how to proceed. Jim
 
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Old 07-09-16, 10:04 AM
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With everything connected but turned off, measure the resistance between the frame and your ground rod. Should be near zero.
 
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Old 07-09-16, 11:03 AM
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Was it a digital multimeter?
 
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Old 07-09-16, 12:46 PM
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Thanks for the quick responses.

Yes digital multi-meter.

I tried to check ohms and it looks like zero. But motorhome has been moved and I can just barely reach from frame to ground rod with leads and see meter face! Will be able to get trust-able reading in the morning.
 
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Old 07-09-16, 01:22 PM
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Did you confirm you actually had ground at your new receptacle?
It is not uncommon for a motor home to have a leak to ground.

0 ohms is a dead short. OL or infinity is an open.
 
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Old 07-09-16, 05:51 PM
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I tested everything with one of those 3 light receptacle testers and everything shows good.

To confirm I used the multi meter from black to ground at receptacle and shows 120.5 volts.
 
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Old 07-10-16, 05:08 AM
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This post was in error, motorhome was not plugged in.
 

Last edited by jjrbus; 07-10-16 at 07:28 AM. Reason: ID10T error
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Old 07-10-16, 05:26 AM
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What does the meter read when you touch the leads together?this is what you would read if there was a dead short.
 
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Old 07-10-16, 07:26 AM
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My last post is wrong, motorhome was not plugged in!

When touching leads from meter together on the 20k it reads 0.00 when touching lead to motorhome frame and house ground rod numbers fluctuate a bit and then settle on 0.00. There is still no AC voltage going from frame to ground rod.

All electric ac and dc is grounded to frame in motorhome. I have a GFI and plugged motor home into it and it did not trip. Jim
 
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Old 07-11-16, 10:17 AM
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I have went through the camper and turned on everything one at a time and checked, I have wiggled cords and cannot get the 53 volts to reappear.

I know the rv refrigerators can cause issues but mine is not even plugged in.

Any Guess's? Why 53 volts?? Jim
 
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Old 07-11-16, 12:19 PM
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It's a phantom voltage reading detected by overly sensitive digital meters. When wires are floating in free air (not connected or grounded), they can pick up small charges from magnetic fields which the digital meter can detect. An ungrounded wire with no connected load is basically an antenna. When the circuit has any type of load connected these minuscule charges immediately dissipate and the meter will read 0V.

Whenever you get a DMM reading that is not around 120V or 240V, first check the battery is fresh in the meter, then assume you have an open connection somewhere. Another technique is to use a simple neon bulb or solenoid tester or plug in a basic incandescent table lamp on the circuit you are testing.
 
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Old 07-11-16, 12:23 PM
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It seems everything is ok now. You don't measure any voltage, you verified that the frame of the motorhome is actually connected to ground, and you are using a GFCI. Don't really have an explanation for why you felt a tickle and why you measured 53VAC. It's not unusual for digital meter to pick up stray AC and give a false reading if the leads are connected to open circuits, but that should not have been the case.

I assume you have tested the GFCI by using the test button, and then when you do this, power to the motorhome goes off?

You said you were working on the motor home at the time. Were you using a power tool?
 
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Old 07-12-16, 12:04 AM
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I was getting shocks so not phantom! Not using power tool.

I will keep an eye on this, makes me a bit nervous.

Thanks for all the responses, greatly appreciated. Jim
 
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Old 07-18-16, 09:03 AM
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This is making me a bit nervous. I have checked everything I can think of and sometimes I get a bit of a tickle and mostly I don't.

Today I checked again with a multimeter and it showed 23.6 volts, with the air conditioner and nothing else on. I turned the AC off and am still showing 23.6 volts?

JIM ??
 
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Old 07-20-16, 12:32 AM
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I remembered something. decades ago while at work we stayed in a newly built bunkhouse in Hornel NY. When showering some people were getting shocked. It was random with no pattern to it.

Electricians and engineers and safety inspectors, people from the state and county, anyone they could find were brought in with all kinds of gauges and meters.

These were not large knock you out type shocks. They never did find a fixable problem.
Jim
 
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