Electrical shocks problem

TenOC wrote:
This is why I NEVER put plastic blocks under my stabilizing jacks. It may not be the best ground, but I want metal stabilizing jacks on dirt..

Metal jacks on DRY "dirt" does nothing at all to prevent shocks.

One would have to SOAK AND SATURATE the dirt with loads of water with minerals to even get a tiny effectiveness.

Then you would have jacks that simply sink right into the MUD.

Starting with a KNOWN GOOD electrical service entrance ground connection is the BEST WAY to prevent electrocution. Modern day electric service entrance requirements is at least TWO SIX FOOT ground rods driven below the surface of the ground and separated by no more than six feet apart.

The ground rods must be bonded together then the ground wire must be connected at the service entrance box and the neutral and the ground most be bonded together INSIDE THE SERVICE ENTRANCE BOX.

That puts the neutral and ground wires run throughout your home at the same ground potential.

Many older homes and campgrounds with old electrical systems are grandfathered and may have only ONE ground rod or worse, use only the water line to provide a ground connection.

A RV breaker box however is considered a downstream breaker panel or sub panel and is treated a bit differently when it comes to the ground wire and neutral wire.

A sub panel MUST have totally separated ground and neutral bus bars and depends on the connection via the shore cord from your home or campground outlet/panel to provide the neutral/ground bond.

The OP simply needs to do some easy trouble shooting working back to the service entrance.

Start at the trailer breaker panel, make sure the panel is wired correctly, the neutral and ground from the shore cord MUST be on completely separate bus bars.

IE green ground wire from shore cord must be connected only to bare or green ground wires on one bus and the white from the shore cord must connect only to white wires on one bus only.

The black wire from the shore cord must connect to the master breaker (in the case of 50A Black and Red of the shore cord must connect to the master breaker).

If all that checks out then proceed to check the shore cord with an ohm meter to verify no broken ground connection exists on the shore cord and plug.

If that checks out, check to verify the adapter plug if used to adapt trailer to 15A/20A home outlet has no broken connection for the ground.

Verify any extension cords if used are wired correctly and no broken or switched wires exist on those cords.

If all of that checks fine then move to testing the home or campground wiring to verify no switched wires or missing ground..

Now if the OP is using a generator and is finding a hot RV skin that is different problem called a floating ground.. In that case this is to be expected since the generator whether a portable or built in type has no way of being connected to earth ground.. Powering a RV via an inverter can also show a voltage and is also expected due to no earth ground connected to the inverter.

CA Traveler wrote:

Chipfo wrote:
the plug is good because I have the ground wire screwed to a rod 4 ft into the ground

That sounds like your open ground. Why didn't you use the ground wire from the utility service panel?

It is a plug I put outside of my house, new home run to the breaker box, I did use the ground in the breaker box, I grounded it again at the plug just because I had the stuff. Now I have the RV grounded to that rod until I figure this out.

This RV is what my father lived in when he passed, it really isn't travel worthy, it was one of those he bought on site on Lake Palestine TX and didn't move it. Everything still works except the original A/C unit, it would be a great deer lease camper, or on-site like he bought it. It made the 3 hr trek here at my house, I use it for tools and materials, I remodel houses.

Chipfo wrote:
the plug is good because I have the ground wire screwed to a rod 4 ft into the ground

That sounds like your open ground. Why didn't you use the ground wire from the utility service panel?

Well I took my volt meter and used it to see if the ground was completing a circuit by touching a prong on the wire and one on the frame and it was a good connection, did the same with the ground wire and the breaker housing and it was good, the plug is good because I have the ground wire screwed to a rod 4 ft into the ground, and I tested it also. I am going to check polarity of the plug to be sure and all the outlets and switches for loose wires.

Chipfo wrote:
Oh wow, thank you all for the prompt responses, I have a lot of things to check now.

:) :)Don't worry I have had it unplugged since I knelt on a bare knee and got zapped. :) :)

Thanks ya'll, I will post back what I find.

Chip,
That would be appreciated as some of us like to collect these events to add to the experience file that helps others.

Matt

Cut n Paste The Fatal Current

The Fatal Current

Strange as it may seem, most fatal electric shocks happen to people who should know better. Here are some electro-medical facts that should make you think twice before taking that last chance.
It's The Current That Kills

Offhand it would seem that a shock of 10,000 volts would be more deadly than 100 volts. But this is not so! Individuals have been electrocuted by appliances using ordinary house currents of 110 volts and by electrical apparatus in industry using as little as 42 volts direct current. The real measure of shock's intensity lies in the amount of current (amperes) forced though the body, and not the voltage. Any electrical device used on a house wiring circuit can, under certain conditions, transmit a fatal current.

While any amount of current over 10 milliamps (0.01 amp) is capable of producing painful to severe shock, currents between 100 and 200 mA (0.1 to 0.2 amp) are lethal. Currents above 200 milliamps (0.2 amp), while producing severe burns and unconsciousness, do not usually cause death if the victim is given immediate attention. Resuscitation, consisting of artificial respiration, will usually revive the victim.

From a practical viewpoint, after a person is knocked out by an electrical shock it is impossible to tell how much current has passed through the vital organs of his body. Artificial respiration must be applied immediately if breathing has stopped.

The Physiological Effects of Electric Shock

The chart shows the physiological effects of various currents. Note that voltage is not a consideration. Although it takes voltage to make current flow, the amount of shock-current will vary, depending on the body resistance between the points of contact.

As shown in the chart, shock is relatively more severe as the current rises. For currents above 10 milliamps, muscular contractions are so strong that the victim cannot let go of the wire that is shocking him. At values as low as 20 milliamps, breathing becomes labored, finally ceasing completely even at values below 75 milliamps.

As the current approaches 100 milliamps, ventricular fibrillation of the heart occurs - an uncoordinated twitching of the walls of the heart's ventricles which results in death.

Above 200 milliamps, the muscular contractions are so severe that the heart is forcibly clamped during the shock. This clamping protects the heart from going into ventricular fibrillation, and the victim's chances for survival are good.

Danger - Low Voltage

It is common knowledge that victims of high-voltage shock usually respond to artificial respiration more readily that the victims of low-voltage shock. The reason may be the merciful clamping of the heart, owing to the high current densities associated with high voltages. However, lest these details be misinterpreted, the only reasonable conclusion that can be drawn is that 75 volts are just as lethal as 750 volts.

The actual resistance of the body varies depending upon the points of contact and the skin condition (moist or dry). Between the ears, for example, the internal resistance (less the skin resistance) is only 100 ohms, while from hand to foot is closer to 500 ohms. The skin resistance may vary from 1000 ohms for wet skin to over 500,000 ohms for dry skin.

New Jersey State Council of Electrical Contractors Associations, Inc.
Bulletin VOL. 2, NO. 13
February, 1987
Submitted by Paul Giovinazzo

Provided by Elmwood Electric Inc.

OK...I will buy that. If you were getting true capacitive coupling you could actually get a full 120V. There is no reason it would be half.

babock wrote:
I would love to hear your explanation why you think you would get 60V.

With an open ground, the only place you will measure voltage is from hot to neutral.

Is it ok for somebody else to throw in an answer? There are two causes of measurable voltage on an open RV ground. One is the wiring. With the ground wire running parallel to and generally physically in-between the hot and neutral, there's capacitive and inductive coupling between the connectors. The hot tries to pull the ground wire up to 120, and the neutral tries to keep it at zero, so it ends up at the mid point of the two voltages. The other cause is electrical devices in the RV. The switching power converter generates electrical noise that has to go somewhere. Whatever gets absorbed by the metal case is conducted to the ground wire, and internal noise filters can conduct the noise to the ground. One side of the water heater element is at 120 volts and some of that is going to leak to the grounded metal tank. Any electronic device may have a noise filter and/or surge protection that lightly couples the hot and/or neutral to ground. Ideally everything would be balanced and the unconnected ground would float at 60 volts. In the few times I've intentionally tested it, the chassis floated in the 40 volt ballpark.

It's easy to demonstrate any of this. For the wiring, just take a roll of romex 100 feet or more. Connect the 120 volt hot and neutral at one end and leave the ground unconnected. With a high impedance meter (most are high impedance these days) measure between the hot and ground wires, and the neutral and ground wires, and each will read 60 volts.

wa8yxm wrote:
On a 30 amp RV plugged into shore power with NO GROUND (Open ground) you should see 60 volts chassis to ground or chassis to neutral or chassis to hot.

I would love to hear your explanation why you think you would get 60V.

With an open ground, the only place you will measure voltage is from hot to neutral.

One common problem, is the use of adapters. The hockey puck style are not of the best quality. A dog bone style is much better.
The ground and neutral in RVs are not connected in the rig. Small leakage is common and if the ground is open causes the skin to be energized to some point.
Do not connect them together thinking that will fix the problem. It can make it worse.