Grounding the RV?

[nickandmarilyn]

My wife read the roto chock directions which indicated that you should not use wood or plastic under the landing gear or the stabilizers because your unit would not be grounded and that would be dangerous. Is this a myth? Does the power cord ground the unit? Is is necessary to ground it? In the interest of harmony I am writing, althought I told her to write. Since this RV excursion is my idea....you get the point.

[H. John Kohl]

From an amateur radio point of view the power cord is not a good ground. It is an electrical protection ground. However, I have gotten electricity shock from the frame of our trailer one time so it is not a great ground.
With that said, I do not apply any additional ground to our trailer when it is parked. I guess it would be a good idea to put in a ground stake if we are parked for a long time. Now that opens up a big area of discussion. How long, what type of ground system and where do you tie it to the trailer frame.

I do not understand roto chock directions about wood or plastic since the trailer is setting on rubber which is more of an insulator than conductor.

If I am not getting a shock from the trailer I will not worry about a ground. If I am then I need to chase down the culprit.

Thanks for the post and sorry I could not answer your question.

[bsmeaton]

A true earth ground typically involves a rod extended 36" - 48" below grade. The only way to determine when the depth is sufficient is by using a meter. The electrical inspector typically verifies true ground when your house is built.

I agree with John - the landing gear or jacks do nothing, so use what you want. BTW - did you know there is enough Carbon fiber content in your tires to conduct high energy electricity such as lightning or 13K from high power lines!

I'm assuming because Rotochok doesn't even know how to spell "lightning", that most of that info was fabricated nonsense to justify the aluminum clad high density polyester pads over the competitor designs, including the gorilla pads (BTW, aluminum is not a suitable grounding material by any stretch, as it melts at a much lower temperature than what is required to ground lightning). I'm a rotochok fan, but I think they need to stick to making wheel chocks.

Careful grounding your Monty. They are designed to stand free with no qualified earth ground beyond a option connection to AC. By grounding your rig, you could be creating a lightning attractor and I would not want to be watching TV with the antenna up in a storm.

[waldo238]

In order to see what you're grounding is you would have to ground the rig and MEG out certain distances out to see what you're reading is. In my industry this is what we do to check the grounding at any cell site which also tells you how far you need to stick a ground rod in the ground and or chemical rods. I don't think all that is necessary for our application as what was already said the thing is sitting on four big rubber tires.

[ole dude]

Say Brad, wheres your little picture--Quack Quack

[bsmeaton]

quote:Originally posted by waldo238I don't think all that is necessary for our application as what was already said the thing is sitting on four big rubber tires.

Do my tires protect me from lightning?

quote:Originally posted by ole dude

Say Brad, wheres your little picture--Quack Quack

Oops, I forgot to use it!

[waldo238]

Point taken. All in all you have no control where and what lightning will hit.

[Steve and Brenda]

This needs to go to "MYTHBUSTERS" to be busted. Using plastic or rubber on the landing gear isolates the vehicle from earth ground is myth since the landing gear seldom comes into contact with a surface suitable to complete an electrical circuit. Most of us park on a concrete surface while at a campsite. I'll stake my 30+ years in electronic maintenance and engineering that dry concrete is a very poor conductor of electric current. We verify the insulative properties of a concrete floor quarterly in one of our static free labs. Therefore, using landing gear pads is immaterial in vehicle grounding. I have access to equipment most do not, one being a hand cranked PSM-2A mega-ohmeter, and I can state that a RV with gear down on concrete, not connected to external power, is not grounded.

Yep, your ground is done through the power cord. If you're using a 50 amp cord, two of the four leads are power, one is power neutral and last one of the leads is earth ground. If you are using a 30 amp cord only one lead is power, the other two are neutral and ground.

If you are getting shocked by touching the frame you are either discharging YOUR body's static electrical charge to ground via the frame (many volts, little amperage) or the vehicle is not properly grounded, the fault likely is poor wiring at the park's power pedestal. One way to check out the ground at the power pedestal is to take a decent multimeter and measure the voltage difference between the neutral line and the pedestal's metal casing. There should be no AC voltage read because there should be no difference of electrical potential between the neutral and ground. If you do read voltage then either the ground or neutral is bad and, usually due to poor contact at the plug, and the park's staff should be contacted. I'm sure there's a tool for this to autotest a 50 amp plug, I built one on my own to verify pedestal line phasing and grounding but I'm sure there's a commercial version out there.

Now, if you wanted two paths to ground which would really mess up things, park on soil highly concentrated in salts, drive an anodized rod into the earth, connect it to the gear with quality copper cable, wet the ground around the landing gear and as your rig sinks nose first into the muck and mire current MAY discharge through the landing gear instead of return to park power neutral and ground. The only thing you're gonna do is confuse your electronics, cook whatever earthworms and fry the little bugs that are in the area.

[Waynem]

Love it Steve, love it.

I got into a very lengthy discussion many, many years ago about grounding HAM radios. It was with an electrical engineer. My question was and is, if you run a wire from your equipment to a rod stuck in the ground, and the lightening hits the ground, where does it go? My theory is that if it is close enough to you it will travel up the wire and fry something in the equipment.

Lightening has a path of its own. Case in point. A friend in Mississippi had a nice shop in his basement. Had a 100 Foot tower with many antennae running ot his Amateur Radio eqipment. In the middle of his basement was a wood table 3Ft wide by 6 Ft long. There was nothing connected to this table. All he used it for was to disassemble equipment. He had a radio disassembled with the case and radio laying on the table. he left the house and was gone for several hours. When he came home, the radio laying on the table looked like an Arc Welder had cut through the middle of it. Lightening had come down the antenna, jumped across to the table, messed up the radio beyond repair, and disappeared. The HAM radio hooked to the antenna had 1 resistor and 1 capacitor destroyed. (That is about $3 in todays prices) but the radio on the bench/table with nothing connected to the table (no power, nothing) was destroyed.

I'm just going to drop the landing gear and hook up. I hope insurance will cover everything that happens - if it happens.

[MacDR50]

Ditto on lighting seeming to have a mind of its own. I was on a destroyer southeast of the Florida coast when we had a real savage rain and lightening storm. While I was on the bridge a bright white ball of lightening "landed" on top of the forward gun, then jumped around the top forward rails and disappeared aft somewhere. We all lost our night vision and had to call up another watch to take over. The whole process took maybe 2 seconds, blistered the paint on the gun and blew off the end muzzle cap. The plastic coating on the rails was melted and one stanchion was spot welded to its deck bracket. The armatures and rotors on two electric motors on the gun platform were shorted out and had to be replaced. We were interviewed by some scientists when we got back to home port but I never heard what they concluded. Yes we were in the Bermuda Triangle.

BTW we didn't have a ground rod driven in :-)

[MacDR50]

http://www.lightningsafety.noaa.gov/outdoors.htm

Once again your public servants have taken steps to protect you.

[Waynem]

Yeah! But what do they know. Most plumbing now-a-days is PVC or CPVC which is a plastic. Oh! Water is inside the PVC and it is a good source of conductivity so the lightening will follow the water to the ground (NOT). The PVC will melt first - maybe.

This could end up as a very controversial subject, don't 'cha think?

[Trailer Trash 2]

I have always wonered about this topic and never got a realy good answer. I was told that if the water pipe that is in the ground (being Galvinised) and had a length of 12 feet or longer it could pass as a earth ground for a home so it should work for a R V, a simple battery cable jumper to the water spigot and the other end to the trailer frame should work as a good ground.
BUT what happens when you use the Gen set only that unit is not grounded in any way so do you run a ground for that the same way???? gen set to a grounding rod.

[Steve and Brenda]

quote:Originally posted by Trailer Trash 2

BUT what happens when you use the Gen set only that unit is not grounded in any way so do you run a ground for that the same way???? gen set to a grounding rod.

Don't confuse earth ground with a voltage return path. If you're using a generator independently, the generator's stator, voltage regulator, etc. need a complete circuit path to provide power to your vehicle. That closed loop creates the difference of potential needed to light the lights in the RV.

I certainly would not want to ground a RV with a generator running because current will always find the path of least resistance. IF your RV's wiring is poorly maintained, it is possible that the earth ground would be more favorable than the generator's neutral line reducing the capacity of the generator. IF you're in the earth ground path, the current would flow through you making RV your stay a memorable one.

[Trailer Trash 2]

"Don't confuse earth ground with a voltage return path. If you're using a generator independently, the generator's stator, voltage regulator, etc. need a complete circuit path to provide power to your vehicle. That closed loop creates the difference of potential needed to light the lights in the RV.

I certainly would not want to ground a RV with a generator running because current will always find the path of least resistance. IF your RV's wiring is poorly maintained, it is possible that the earth ground would be more favorable than the generator's neutral line reducing the capacity of the generator. IF you're in the earth ground path, the current would flow through you making RV your stay a memorable one."


I often wondered why Honda put a seperate grounding screw on there generators ( I'm not talking about the DC ground )
just what is it supose to be used for.