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Old 02-06-2016, 02:03 AM   #57
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Originally Posted by NMRVer View Post
Wet wood will conduct. A person grabbing an energize RV will conduct better. With this said and being an electronic engineer for over 30 years, the wood blocks are not the cause of hot skin. It's caused by improper grounding via shore power or generator and earth's potential. The RV has a higher voltage than earth which causes current flow through a human's body. My .02
I can see the earth's the potential on shore power, since the grid uses it, but not on generator.

With the cord unplugged there is no earth connection in generator produced ower.
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Old 02-06-2016, 06:22 AM   #58
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The generator neutral and safety ground are connected together (bonded) on their side of the transfer switch. RV's have their safety ground and neutral connected at the power box connection per code. A simple continuity check of that would verify whether or not that connection was present. Checking that is a lot better answer than any GFI setup.

The reason one gets a hot skin is the metal of the RV does not have that connection. There are a couple of ways for some voltage to build up without that connection. Some worse than others in terms of safety. Anyone worried about it should learn how to check whether or not the safety ground and neutral are connected. It not a good idea to "fix" it by connecting them together in the RV as that bypasses the safety sensors in any units that have them.
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Old 02-06-2016, 06:43 AM   #59
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Originally Posted by nothermark View Post

RV's have their safety ground and neutral connected at the power box connection per code.
I am by far not a fully educated licensed electrician and know enough about this stuff to be very dangerous to myself at times.

However, it was always my understanding that the Ground and Neutral in the RV shore power box had to be separate, not bonded together as the shore power supply box is considered a sub-panel, NOT a main panel.

Is it not true that MAIN panels will have the ground and neutral bonded together? Plus there will be a ground rod buried in the ground to a specific depth I believe.

Dr4Film ----- Richard
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Old 02-06-2016, 07:43 AM   #60
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Hot skin refers to a voltage present on metal components of the RV usually caused by deficiency in the electrical system inside or outside your RV. If the RV is properly bonded and grounded no such condition can occur. Don't let the "grounding" part of the EGC confuse you. It's really the equipment bonding conductor. Don't think in terms of "grounding" equipment, connecting it to the earth. Think in terms of connecting it to the system grounded conductor or the grounding electrode conductor (or both). Remember, the low-impedance fault-current path you create is necessary for overcurrent protection devices to operate. Earth is not a low-impedance fault-current path.

Ground current (voltage) is a dangerous condition This problem occurs when part (and at times all) of the return current in the neutral conductor flows through grounding conduit and conductive parts of the MH back to the service entrance. This current is called ground fault leakage current. It can generate disturbances and other problems such as High voltage differences between separate grounding points, which may be dangerous.

If you have a hot skin you need help with finding the fault with Bad shore power plug connection, Improper grounding, no grounding, reversed polarity, Improperly wired extension cords usually caused by a park owner, employee or guest improperly rewiring an extension cord, Improperly wired 30 amp adapters, Loose or worn power outlets,Reversed polarity in electrical outlets in the RV.

An AC tester, for example a Fluke VoltAlert is an easy way to test for hot skin. AC testers are available at hardware stores for around $30. anything over 2 volt is a problem.
Everything in my boat is bonded from the rails, window frame, to the engine and connected to an underwater bonding plate.
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Old 02-06-2016, 08:14 AM   #61
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Hot skin refers to a voltage present on metal components of the RV usually caused by deficiency in the electrical system inside or outside your RV. If the RV is properly bonded and grounded no such condition can occur. Don't let the "grounding" part of the EGC confuse you. It's really the equipment bonding conductor. Don't think in terms of "grounding" equipment, connecting it to the earth. Think in terms of connecting it to the system grounded conductor or the grounding electrode conductor (or both). Remember, the low-impedance fault-current path you create is necessary for overcurrent protection devices to operate. Earth is not a low-impedance fault-current path.

Ground current (voltage) is a dangerous condition This problem occurs when part (and at times all) of the return current in the neutral conductor flows through grounding conduit and conductive parts of the MH back to the service entrance. This current is called ground fault leakage current. It can generate disturbances and other problems such as High voltage differences between separate grounding points, which may be dangerous.

If you have a hot skin you need help with finding the fault with Bad shore power plug connection, Improper grounding, no grounding, reversed polarity, Improperly wired extension cords usually caused by a park owner, employee or guest improperly rewiring an extension cord, Improperly wired 30 amp adapters, Loose or worn power outlets,Reversed polarity in electrical outlets in the RV.

An AC tester, for example a Fluke VoltAlert is an easy way to test for hot skin. AC testers are available at hardware stores for around $30. anything over 2 volt is a problem.
Everything in my boat is bonded from the rails, window frame, to the engine and connected to an underwater bonding plate.
ladagobago
When I use my Fluke VoltAlert anywhere on the white sheet metal skin of the Splendide washer/dryer in my coach it indicates a hot skin condition.... but only when the tumbler is rotating or spinning.
Is that something I should be concerned about?
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Old 02-06-2016, 09:56 AM   #62
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It is possible that the rotating drum is generating a static charge somehow via tumbling items inside or friction between drum and stationary seal.

That may cause the indicator to react...not familiar with the device so can't comment on it.

However you can use a voltmeter to measure any voltage from the skin of the machine to a known good ground.

Since machine is indicating plug an extension cord into another outlet that is known to neutral good and correct and use it for reference.

Do NOT wiggle any part of the power connection for the unit until measured just in case you have an intermittent connection.
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Old 02-07-2016, 09:56 AM   #63
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I am by far not a fully educated licensed electrician and know enough about this stuff to be very dangerous to myself at times.

However, it was always my understanding that the Ground and Neutral in the RV shore power box had to be separate, not bonded together as the shore power supply box is considered a sub-panel, NOT a main panel.

Is it not true that MAIN panels will have the ground and neutral bonded together? Plus there will be a ground rod buried in the ground to a specific depth I believe.

Dr4Film ----- Richard
I was surprised at the bonding arrangement when I sorted it out by reading various articles on the code for motor homes. It is true that there should not be a bond between neutral and ground in the motor home on the shore side of the transfer switch circuitry.

The generator side of the transfer switch should have the ground and neutral bonded so that the house gets bonded that way when on generator.

The box on the post should have a neutral to safety ground bond and a ground rod in a park.

I will not argue that I have seen systems where I did not see a ground rod handy but I will say that I have seen one's with a ground rod at the post.

I suspect at least part of the issue with post grounding is an issue of local conditions. I have not kept a log of every place we have camped but I will note that some places have a very spread out system with room between units so each post is probably 1 to 4 boxes and probably grounded at the post. Other places have the pickle park clustering where each post is 4 units and there is a bigger meter or disconnect panel fairly close by so it can serve a cluster of posts. Depending on local interpretation they may ground at the meter panel and treat the posts as a sub panel.

As I recall the OP was in a temporary setup of some kind. If that is the case and it was wired by the typical industrial electrician they may well have treated all the "posts" as sub panels as that would be the code for most things but not RV's. Tricky stuff, that code. Easy to get something missed or broken in those big temporary setups.

My takeaway was to start packing a non contact sensing pen. There are a slew of suppliers starting at around $7 less any coupons at Harbor Freight. I think Home Depot is under $10. Given the ease of checking and propensity to get lost or broken I can go cheap on something like that. It occurs to me they might be a better tool to recommend to the folks who are afraid of sticking a meter probe into live circuitry. I need to play with one a bit more before starting to advocate using them as a trouble shooting tool.



Just for grins I did a quick search. Out of the first page these gave a clear answer in the first few paragraphs:

120 VAC in your RV

Generator Ground-Neutral Bonding | No~Shock~Zone

https://www.civicsolar.com/resource/...-boats-and-rvs
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Old 02-09-2016, 06:45 PM   #64
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So after reading through this thread and the reference articles on portable generator lacking a ground\neutral bond I did some experiments on my coach. With my Honda EU2000 plugged into the coach I found 64 volts N to G and 64 volts L to G and 128 volts L to N. The coach monitor displays an error. With the mentioned ground neutral bonding plug installed I get 128 volts L to N, 128 volts L to G and 0 volts N to G. Monitor displays all is ok. This has been a great thread and thanks to all who posted up. Valuable information to say the least.
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Old 02-10-2016, 06:18 AM   #65
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FWIW - I think this is information anyone running an external generator should be aware of. That said I bet most are not.
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Old 02-10-2016, 08:37 AM   #66
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FWIW - I think this is information anyone running an external generator should be aware of. That said I bet most are not.
I've been using the same Honda gen for years with my old coach which was not equipped with a monitor. I'm sure this condition existed in the old motor home as well. I just didn't know it.
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