Wayne Dohnal wrote:

As noted in the previous post, the coupling in the wires will energize an ungrounded RV frame with a small current. As a science experiment, if you take a roll of Romex and hook the black and white wires up to the AC line, the unconnected ground wire will measure about 60 volts from either the black or white wire with a high impedance meter. It floats at exactly half the difference of the two energized conductors. In practice, an even bigger culprit is the typical power converter. They generally leak a few milliamps to the safety ground, and if it's not earth grounded, it becomes hot enough to cause a tingle type shock. It's all perfectly normal.

opnspaces wrote:



Ooh I'm going to go try that one. Hope I don't earn a Darwin award.

Salvo wrote:

There's a very simple test to determine if the "tingle" is dangerous. All you need is an AC digital voltmeter and a 4.7 K ohm, 1/2 W resistor (from Radio Shack). Connect the resistor between electrical outlet ground and RV chassis. Hook-up AC voltmeter across resistor. Turn on AC power to MH.

If voltage reading is less than 23V (equivalent to 5 mA), then the system is safe.

Current is:

I = V_meter / 4.7 k ohm

Sal

john&bet wrote:

Ok all you electrical people or think you are. My trailer would tingle you when pluged into 30amp. shore service with a good ground and trip the 50amp. circuit breaker at the shore pedestal instantly when turned on. What is the problem? Oh yes the wiring was pinched between frame and floor with the two hot leads touching each other and just a stray strand touching the frame. Not enough current flow to trip 30amp. shore power c/b, but get you bit if bare footed and steped on steps and ground or touched frame laying on ground. A Keystone dealer fixed under warrenty after they first told me they did't find problem. They only checked it at 30amp. service not the 50amp. problem as I told them. After a very serious face to face chat they pluged into a 50amp. service and found problem real fast. I don't think you can get a 2 pole 50amp. Gfi circuit breaker and 30amp. circuit breakers are expensive but availabe. 30 amp. gfi recepticals are not made also. This is my experince with a tingling frame. Just grounding does not make all well.

Harvard wrote:



Your example is an exception to what we see on this site about 10-15 times per year, that is being an floating AC ground "tingle". Your circumstances were obviously much more serious in that the short was able to generate a voltage on the chassis with a ground path intact, weak maybe, but intact to some degree.