Daisy,
Yes, there is a so-called phantom possibility for a number of reasons with
all electricity types and voltages. It is very common and overlooked. There
are other terms such as Eddy current. Another misnomer is that you cannot be
shocked by DC, only AC. Every ignition coil and taser is DC, 10,000 volts
and up.
To much to discuss here, the most common causes are corroded or deteriorated
ground especially where bi-metal connections ocur. Much effort should be
made to have EVERY bulb, fixture, and appliance provided a dedicated ground.
Trailers and everything vehicular were notorious for utilizing single power
feed lights, especially clearance lights mounted to the shell with no ground
wire. The mounting corrodes and the light won't work. In the right
circumstance, a field current can set up similar to a capacitor. It won't
shock you. It can cause very high DC voltages, with little current.
Let me give all on the list a common example: You have a three bulb yard
light on a decorative post. One of the lamps keeps burning out it's bulb.
The other two do not. What happened? Well, if installed properly, the
beautiful ornament lamp and post had it's unshielded copper wire mounted to
the post and fixture for safety. All the black or "hot" wires were properly
tied together, all the whited so-called "ground" neutral wires were properly
tied together. Despite a good installation, the little fire ants who just
love electrical fields, found an entrance killed themselves, continued to
amass, provided a nice environment for moisture and corrosion, and one white
wire finally got a poor connection. This set up a capacitance eddy current,
supported by that unshielded properly installed safety ground wire. Add the
distance of the buried feed wire, the bi-metal of the ornate pole, the ants,
the moisture and corrosion, and you have a phantom voltage that can achieve
up to 400 volts from a simple 120v supply. It just keeps blowing the bulb
with over voltage. It is simple to fix, will fool a GFCI protector, and can
drive you crazy trying to find the bad connection.
One "repaired" wall outlet in your home or RV with the wires reversed can
corrupt the entire trailer or home, as soon as you plug in a device. This
can kill anyone on a wet day who touches the trailer door knob. Just get in
the habit of back-hand touching everything for just a moment before you grab
anything wired.
Did you know: All wall plugs should have at least two slots to plug in
something. The widest slot is the so-called "ground" or neutral. Only the
white wire should be connected to that slot or side of the outlet. An outlet
is called a duplex. The outlet usually three wires: an unshielded ground, a
white, and a black. The black goes to the copper colored screw for the small
slot. The white goes to the silver and sometimes black screw for the wide
slot. The unshield wire when available goes to the green screw, or the screw
that is part of the metal support.
Did you know: More often than not, the colors are reversed in automotive and
trailers? Black is ground! Red usually "hot", sometimes white is "hot" too.
In trailers, you are likely to find a hodge-podge mix of colors that often
are not consistent within the trailer. You just got to use a test light for
the DC circuit and a voltmeter. Go to Depot or Lowes and get a $9 pocket
voltage probe to check anything AC. They work. It can save your life. Just
probe any outlet, cord, bulb, or shell part of your trailer or home. It must
not light and buzz on anything you can touch or any wide slot of a wall
plug.
I can give you perfect tips for safety, checking, and repairs for a very
real and common problem, especially in trailers. If phatom or eddy current
did not exist, no touch lamp would ever work. If it did not exist, you
wouldn't become a walking capacitor in the winter as you crossed your
carpet, touched the fridge, stove, toaster, etc, and zapped yourself! So you
are correct, it exists, probably from your old 12 DC converter full of dust
holding moisture, or a corroded connection. Electical field presence is
every where, even in you. That's a good thing.
-Eddie-