Grounding Your Camper

[GeorgeTelford]

Hi Warpony

I hope you dont, yet anyway, surely an extension lead is against code if used in a trailer? There is no way to bond that to the trailer

[TD4FREEW/CTD]

this is an interesting topic.

the breaker box or "sub panel" being used on these trailers should have a floating nuetral bus, that is, not continuous to the ground or chassis in any way. this will help to reduce reverse polarity electromacution. after hearing the war stories you guys have, i would definatly bring a cheap multi-meter to the camp grounds. check for voltage first between the hot and ground side. you should get at somwhere in the neighborhood of 110-120 volts. if voltage is lower than that, the ground is most likely not good. next check for voltage between ground and neutral. if you read any significant voltage (10+) between the two, more than likely one of them is bad. check for voltage between the hot and both neutral and ground. i dont know if they have 240 volt setups at camp grounds, but if they do, for gods sake make sure you are setup properly!

one idea is to attach a ground strap to your vehicle. it might be an idea to use a 3'-4' conductive, preferably copper, rod. use a peice of stranded armored ground cable and attach it to your ground bus. drive the steak into soft, moist ground and it should provide a decent ground. you could even moisten the area yourself before driving the rod. as a test you could check for voltage between your ground bus and the campgrounds power before you hook up. if voltage is good you are grounded like a mofo!

i have been contemplating this very grounding dillema.

where theres a will.....

[Miriam C.]

War Pony and All
Please don't leave out the most important part of your build. Breakers are very cheap. GFCI's are not hard. There are at least 2 real good examples of how to wire them on this sight. One is Tom Swenson's. If you print them and follow thier examples you should be fine. The Generic Benroy is done well too.

I have no experience with the Yellow cords but I really believe a correctly grounded breaker is so necessary When you hear the storys or rain outs and fires here. Campers should be treated as your home, or use battery powered everything. *(D cell type)

Miriam

[TD4FREEW/CTD]

keep in mind that the proper function of a GFCI breaker or outlet is dependent on a GOOD functional ground. without proper grounding a GFCI is USELESS!

[Boodro]

TD4free, a few observations on your post . If you want to ground your breaker bus or TD frame to earth ground ,you could use a good pair of jumper cables . about driving a ground rod, it would hgave to be at least 4 ft , preferably 8 ft long to do a good job. The biggest issue I could see about driving a rod into the ground , you don;t know where the elect. lines are underground. You definetly do not want to hit one of those with a groundrod, it would realy ruin your day! Instead of driving your own ground rod , I wouild look around the power pedastal & just clamp a cable to that rod. Alot quicker & easier.
I also don't see why you would want to ground the receptacals to your frame & not ground the frame . Since the tires & tounge crank are rubber , the TD is not grounded. Unless I'm missing something.
Just my 2 sense , ain't worth much!

[angib]

keep in mind that the proper function of a GFCI breaker or outlet is dependent on a GOOD functional ground. without proper grounding a GFCI is USELESS!

You may want to check and perhaps correct this statement. As I understand it, your GFCI works exactly the same way as our RCD (residual current device) - they're the same devices with different names.

The GFCI simply compares the current flowing in the line and neutral conductors and, if it finds a difference, it trips. The only need for an earth is to make the 'Test' button work - it is not needed to trip the GFCI.

Providing protection where the earth is missing or damaged is an important part of the reason for using a GFCI/RCD.

Andrew

[GeorgeTelford]

Hi Andrew, all

If there is no earth present then there would be nowhere else for the current to excape too, that difference between live and neutral current as got to go somewhere.

If you are completely Isolated from earth then the bird on a wire effect comes into play.

This leads many people to Wrongly assume that a total lack of earth is a safety feature, not so

Without a good earth the only possible way to get fried is a straight live neutral short (through you body) if there was no earth you would die, the current passing through you ( a resistive load ) would not blow the MCB until way to late.

Now lets have a fully earth bonded tear, now a LIVE NEUTRAL SHORT through you, as another path, although generally power will take the path of least resistance even a tiny amount of current escaping through another extremity to earth will trigger the RCD.

[bdosborn]

one idea is to attach a ground strap to your vehicle. it might be an idea to use a 3'-4' conductive, preferably copper, rod. use a peice of stranded armored ground cable and attach it to your ground bus. drive the steak into soft, moist ground and it should provide a decent ground. you could even moisten the area yourself before driving the rod. as a test you could check for voltage between your ground bus and the campgrounds power before you hook up.

This is a common myth that a ground rod right at a metal object will afford safety from shock hazards. A lot of people are killed from touching energized light poles that have a ground rod at the base. Here's an article on why a ground rod doesn't reduce touch potential.
http://www.mikeholt.com/mojonewsarchive ... 020429.htm

A functioning ground is *not* a requirement for a GFCI receptacle to work. The GFCI receptacle compares the current on the hot and on the neutral. A difference of 5 mA or greater will trip off the receptacle. The ground need not be present for proper operation.

The best way to minimize touch potential is to provide a low impedence path to ground using the equipment ground (green wire).

The best way to provide personnel protection is to provide GFCI protection.

And of course, we never bond the neutral to the ground anywhere in our trailers.

Bruce

[TD4FREEW/CTD]

please accept my apology, as i was totally wrong about the grounding of the GFCI. im an apprenticing electrician and thats what i get for listening to my boss! he always told me it monitors current between the ground and neutral, but now that i think of it, that makes absolutely no sense! either way, during a building inspection the inspector is going to demand to see a ground at your GFCI, and all other outlets for that matter. some people will try and cheat the ground by strapping the neutral to the ground screw. it will fool a tester, but the inspector will not be happy.


anywho,

if the idea of the ground is to provide the path of least resistance in a short circuit situation, then a functioning (low impedence) ground rod should theoretically do the job. if a short to ground occurs, the ground draws more current than the breaker is rated for, the breaker trips, and the power supply is cut off. underground utilities are definatly an issue when driving a ground rod, however at a camp site they will be minimal. another issue is when camping in dry places like the desert, a 4 foot ground rod will not do the trick. some desert cities make you drive 2 8 foot ground rods. of course, the idea of bringing a ground rod around with you is impractical, and could become dangerous in certain rare situations.

all that being said, i still think the best way to insure a proper ground is to bond your trailer and equipment properly, and test the ground at the source of power with a multimeter. if the ground provided is good, that all you should really need.

thanks for clearing up my misunderstandings!

[bdosborn]

You may want to check and perhaps correct this statement. As I understand it, your GFCI works exactly the same way as our RCD (residual current device) - they're the same devices with different names.

The GFCI simply compares the current flowing in the line and neutral conductors and, if it finds a difference, it trips. The only need for an earth is to make the 'Test' button work - it is not needed to trip the GFCI.

Providing protection where the earth is missing or damaged is an important part of the reason for using a GFCI/RCD.

Andrew

Andrew,

Sorry, I missed your message when I posted mine. I didn't mean to parrot what you'd already said.
Bruce

[bdosborn]

TD4FREEW/CTD,

Don't be so hard on yourself! That's why we're all here, to share our ideas on teardrop trailers.

Bruce

[WarPony]

Man, I'm going to ditch all the 120V plans on my TTT now. This is too much crap to deal with and I wanted to keep it simple. I am glad that this has gone so far. I might have been injured/killed in my ignorance of campground outlets and bad grounding procedures. I did buy and outlet tester on Sunday but it doesn't test for the quality of the grounds or combinations of defects.

[bdosborn]

Get the cord that Tom showed a picture of, use the tester and you'll be fine. You have more chance of dying in an auto wreck on the way to the campground than you do from the 120V if you use reasonable caution.
Bruce

[Micro469]

Man, I'm going to ditch all the 120V plans on my TTT now. This is too much crap to deal with and I wanted to keep it simple. I am glad that this has gone so far. I might have been injured/killed in my ignorance of campground outlets and bad grounding procedures. I did buy and outlet tester on Sunday but it doesn't test for the quality of the grounds or combinations of defects.

Sometimes, too much info is just as bad as not enough. The guy who used the campsite before you didn't fry, and the guy using it after you probably won't fry either.SO... what makes you think yer special??

[GeorgeTelford]

Hi Bruce

You are completely and utterly wrong.

The difference between live and neutral is what springs the GFCI (RCD) but if there is no earth/ground present then the GFCI will never ever trip, it cannot

If there is nowhere for the current to leak to then how can it? Think about it, there is the only place the current can leak to.........

That place is earth/ground.