Hi there ,
After 2 monthes, in Campgrounds, the holiday season is finished...
the weather was not good , particulary near my home, in the north of FRANCE, where I've decided to live in my A/S and work in the same time, during summer. So what a stormy weather and people and i, wondered if the caravan has to be in contact with the earth ground with a wire or a cable, just in case of the storm flashed me...
Do you plug the caravan to the ground ?
Is there an original cable on genuine A/S to put on the ground , how it was and what to do; may be these complete the electrical wiring, to run well ?
your trailer should be grounded through the electrical service. knowing that you use a transformer in europe to convert 220v to 110v, may create additional connections to earth.
you can add a ground wire from the frame of the trailer to a driven ground rod if you plan on leaving the trailer in one place for a long time.
this would help protect your step down transformer from lightning by providing a direct path to ground instead of having to travel thruough the transformer.
you can accomplish this simply by driving an 8 foot ground rod straight down and attaching it to the frame of the trailer with #4 awg wire (about 1/4 inch diameter wire). clamp the other end to the trailer frame, clean the connection point to bare shiney metal and use a non corrosive clamp such as bronze or stainless steel.
good luck with your project.
john
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you call them ferrets, i call them weasels.
I'd like to point out that most trailers are properly grounded when the tongue jack is solidly 'grounded' to the ground surface. However, most of us install a non-metallic object between the turf and the tongue jack that prevents proper grounding.
John, the solution you mention is a good solution to what a lot of us do. I, however, use the Airstream tongue jack plate that is made from aluminum and completes the grounding process through the tongue jack.
Rick,
The jack post/pad is not a reliable grounding mechanism for a variety of reasons. The first is that the path from the trailer 120v electrical system ground, to the trailer frame, to the jack to earth is typically not electrically solid. The connection points between the jack and the frame tend to corrode over time which causes there to be some resistance and the connection between the frame and the trailer 120v ground point can also develop rust or corrosion. In many campgrounds, the area under that jack is either asphalt, concrete or loose gravel which effectively INSULATE the jack from any potential earth (ie damp dirt) contact.
Although most of us don't do it (me included and I know better), a 1/2' copper rod should be driven into the ground at least a foot or so (watered regularly to ensure contact) and attached to the trailer 120V ground connection located at the circuit breaker box. A/S does attach wiring from this connection to the frame, but again, the state of that connection varies as the trailer ages and is exposed to weathering. On later model A/Ss, there is a wiring lug strip where the 12v negative, the 120V earth ground, the connection to the frame along with the wire to the 120v circuit breaker box earth ground are joined together. There are typically additional openings in the lug strip where you can install another wire which could be run to the outside for connecting to a true earth ground.
Depending on campground power for earth ground is at best iffy. If you can measure ANY voltage potential between neutral and ground with a digital multimeter, that means that the ground connection is NOT truly grounded (something I find at LOTS of campgrounds). A few millivolts is normal, but when you find more than a few volts, then the earth ground connection is faulty within the park power.
On the matter of lighting protection, I installed both a 12v and a separate 120V surge protection device mainly to protect the electronics in our rig. There is a strong potential in any campground for lighting based surges to occur was most of the wiring is underground and if lighting hits a tree it induces a current in any nearby wiring as it travels into the ground, which results in a surge of voltage. Wish A/S would install such protection as factory especially since the new units have quite a bit of electronic equipment on board.
David
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david & bret
'02 Bambi LS
'99 34' Limited
Air Forums # 2159
President Heart of Texas Camping Unit
WBCCI # 7548
Your analysis of the scenario we all face is correct; the grounding process is not as good as it could be both in terms of its capability ("the state of that connection varies as the trailer ages and is exposed to weathering") and its inherent design because of the traveling mode of our trailers. If we all parked our trailers (now, that would be painful), then the proper method of installing a metal ground spike, as you deftly point out, could and should be done.
Thank you for adding a measure of reality to the discussion.
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