Mike134 wrote:
enblethen wrote:
Some leakage could be induced into the skin and chassis.
That's a new one on me after 38 years.
Its called "capacitive leakage current".
SEE HERE"In any electrical installation, some current will flow through the protective ground conductor to ground. This is usually called leakage current. Leakage current most commonly flows in the insulation surrounding conductors and in the filters protecting electronic equipment around the home or office. So what's the problem? On circuits protected by GFCIs (Ground Fault Current Interrupters), leakage current can cause unnecessary and intermittent tripping. In extreme cases, it can cause a rise in voltage on accessible conductive parts.
The causes of leakage current
Insulation has both electrical resistance and capacitance - and it conducts current through both paths. Given the high resistance of insulation, very little current should actually leak. But -- if the insulation is old or damaged, the resistance is lower and substantial current may flow. Additionally, longer conductors have a higher capacitance, causing more leakage current. That's why GFCI breaker manufacturers recommend one-way feeder length be limited to 250 feet, maximum.
Electronic equipment, meanwhile, contains filters designed to protect against voltage surges and other disruptions. These filters typically have capacitors on the input, which adds to the overall capacitance of the wiring system and the overall level of leakage current.
"Typically, as long as all electrical wiring involved including outlets, adapters, extension cords are in good shape and wired properly any voltage developed on the safety ground wire will be zero or near zero at all times.
If the wiring on the safety ground is not present or there is substantial resistance at any connection. Or way too much wire involved from the main breaker panel in the home (where ground and neutral are bonded with the home's entrance panel grounding system) or a fault in the entrance panels safety grounding system it is very possible for enough capacitive leakage current to develop considerable voltage on the "skin" of the RV, enough to give you a good buzz.
Many yrs ago, I remember my Uncle who built a shop, DIYed his panel to the shop and had PoCo connect on to his panel.. Kept complaining everytime on damp days he would get jabbed.. My Dad discovered, my Uncle instead of planting a ground rod or two, just ran the entrance ground wire out and a couple of inches down and out a couple of feet from the building in clay..
His breaker panel was using mainly the PoCos nuetral wire as ground!
A couple of ground rods and wire fixed the leakage..
OPs electrician should have checked and verified that the service entrance panels grounding system is connected and verified zero volts showing anywhere in the house wiring.
OPs electrician should have checked and verified that when the trailer was plugged in that the ground through all adapters and extensions is good and zero volts showing.
OP should have had the electrician check and verify the ground wire from the RV cable into the breaker panel in the RV is in good working order. The breaker panel in a RV is treated as a sub panel of the home so grounds must attach to a ground buss bar and neutrals must attach to neutral buss bar which is electrically isolated from the safety ground.
Because RVs move about, sometimes the connections in the breaker panel get loose, so those connections need to be checked.
OPs garage outlet should have GFCI by today's standards but if it was built before GFCIs were required that is grandfathered unless you remodel the garage electrical system..
Adding a GFCI isn't a bad thing, but in reality if the fault is in the RV electrical system that fault will need to be found and fixed.. Reason being is 30A and 50A shore power panels in campgrounds will not have GFCI on them.
OP could have combo issue, poor grounding combined with one of several possible faults like failed water heater electric heating element, failed/leaky fridge heating element, faulty power converter or leakage from the AC unit.
To troubleshoot the RV circuits, you can turn off a breaker one at a time to see if the voltage on the ground goes away. Once you find a circuit that removes the voltage when the breaker is off you now have narrowed down to one circuit and whatever is on that circuit.
