wa8yxm wrote:
As an aside: Yes, I know that.
Now to the point. What I'm trying to say is this.
If you are holding a metal cased device (Did I mention a Skill hand grinder.. I actually held it) that shorts hot to case (It did) on mains power, which is earth grounded YOU become a "Return path".
In a standard system, yes. And you definitely DON'T want to be that return path!
But since the inverter has no ground.. Even if you grabbed the hot wire with your bare hand (Assuming nobody put in a ground when you are not looking) THERE IS NO PATH it is an open circuit, SWITCH OFF, no flow. (Still I do not recommend it)
Neither do I. I've felt the upside of 120VAC up my arm a couple times. IT definitely don't tingle! It hurts like h3ll!
As to the 60 volts on the ground lead (I do see that and it does tingle a bit)
This is because the ground wire is sandwiched between the black and white in standard ROMEX and in other types they also lay side by side.
Two conductors sepererated by a non-conductor (Dielectric) form what is called a capacitor or condenser (Two names, same device). Given time to do the research and a bit of math I could tell you the capatience per foot of say 14ga.
Well in this case you have two capacitors in the same can forming an AC voltage divider.. In most RV's there is not enough wire for this to pass enough current to do much in the way of damage (Why it only tingles) but that is where it comes from....
Basically a very tiny current flows right through the insulation wire to wire.. A sensitive voltmeter will show 60 volts (1/2 the voltage) a el-cheapo might show less and if you put a load on it (Say a 10 watt lamp) It goes by by fast.
You're talking inductance, right? The 2 current carrying conductors are INDUCING a voltage in the ground wire. And since, in some systems, it's not connected to anything, you measure a voltage, but its with respect to the hot or neutral.
Now, I have an older Xantex MSW unit I recently retired, but just after I installed it many years ago I was working around it with it on (it was providing power for one of my tools). I happened to lean my arm on the case of the inverter (metal casing) and my hand came to rest on the 12VDC negative terminal. There was most definitely a tingle there! I read the manual and it stated the chassis was connected to the ground, and the ground was bonded to the neutral, as per code for an installed power source (which it was). I verified this with my multimeter. I also saw the 12V negative was bonded to the chassis.
Having said that, I don't know if the replacement ProWatt SW unit would do the same. I'd have to meter it.
Cheers!
Mike
