William,
That same third wire, the bare copper in a romex, is what can set up a
phantom or field effect when the white wire faults, fails to do it's job in
part or total, or is reverse connected to any duplex (wall outlet). All the
bare copper and all the white wires connect at origin to the uninsulated
buss bar. All sorts of things can happen on reversed or poor connections.
Yes, you hope the lamp or appliance just won't work on a bad or failed
connection, but many times poor, increased, or even heat production can be
the result. Everything is compounded, if the body is connected, and thus
so-called grounded, to the same buss bar with the bared copper and white
grounding wires. There are just too many scenarios to describe. Industry and
UL have never resolved the safety dispute over grounding a chassis thru the
buss bar is safety or deadly. All depends on quality of work and design mfg.
Done right, it does not matter. Done wrong it can save your life, or just
shock the crap out of you at the very least. Be safe, back-hand touch
everything! Just get into a natural habit of touch first before you grab. It
can save you at the very least, unpleasantness.
Despite the non-believers, phantom, low, high, and transformed voltage can
easily occur. It can and will infact produce so much voltage as to instantly
overvolt and burn out the simplest of light bulbs. A capacitor is just a
simple roll of paper and foil package in everything from Bake-O-Lite back in
the day, to round black plastic, oval gray, silver and aluminum cans, big
giant oil-filled cannisters, and more. To say a pole, house, or aluminum
trailer cannot create a phantom voltage at various levels is simply
incorrect. The lady's electrician is more than correct. The fixes are more
than simple for any layman to check, and safely correct with a $9 volt meter
and a $9 Greenlee Field Probe, both availabe everywhere on a little card
hanging on a rack. You can check a whole trailer in five minutes.
Speed doesn't kill, impact does. Electricity isn't scary, poor work quality
is.
-Eddie- Houston, Texas