Charly,
I suggest you inspect the circuit breaker box at the service entrance to
your house and see if the incoming neutral line is connected to a ground
rod. if not, then I recommend you drive an 8 foot ground rod into the
ground just underneath the breaker service entrance.
Next measure the AC voltage between the ground rod and each of the two
incoming 240 V wires. I'm predicting that one of the voltages will be
significantly lower than the other voltage, probably just a few volts.
If that is the case, and only if that is the case, then connect a heavy
gauge wire between the ground rod and the incoming line that has the lower
voltage. You will now have a grounded neutral, and your station will be
much safer. You should also connect the chassis of each piece of equipment
in your station to the external ground rod. This is not an ideal situation,
but since you have no separate ground wire in your electrical outlets, it
is the next best option.
If your two voltage measurements show an equal 120 V between the ground rod
and the incoming wires, then you are out of luck. That would mean your
electric company is centertapping the 240 V line and grounding the center
tap – a terrible idea but not inconceivable. If that is what you find,
then do not ground either of the incoming lines.
73,
Jim w8zr
Sent from my iPad
On Oct 15, 2013, at 8:10, Charles Harpole <k4vud@hotmail.com> wrote:
PSE SEE MY COMMENTS IN ALL CAPS BELOW.
Charles Harpole k4vud@hotmail.com
> From: 4cx250b@miamioh.edu
> To: amps@contesting.com
> Date: Tue, 15 Oct 2013 07:12:12 -0600
> Subject: Re: [Amps] More on two pin 220vac
>
> Paul has raised a pertinent issue. I find it hard to believe that the
power
> distribution in Thailand or any other country is completely floating with
> respect to ground. Were that the case, then the entire concept of a
> "neutral" would have no meaning. In HV power supplies which have a B+ and
a
> neutral current return, one always anchors the neutral line with a
resistor
> (100 ohms typical) to chassis ground. This is done to keep the B+ from
> soaring uncontrollably. The same reasoning applies to an AC power
> distribution system.
I DONT KNOW ABOUT THE INSIDE OF AMPLIFIERS, BUT I DO KNOW THAT THERE IS NO
DEPENDABLE CONTINUITY VIA OHM METER FROM THE NEUTRAL TO EARTH GROUND ON MY
WALL SOCKETS. FACT. AND, YES I DID BURN UP ONE METER.
> 73,
> Jim W8ZR
>
> > -----Excerpt from Original Message-----
> > > > about 80% of Thailand buildings have TWO holes in the 220VAC wall
> sockets
> > > and ONLY TWO HOLES. One side is definitely hot and the other side is
> > > definitely neutral. The pin sockets, the holes, are not marked and not
> > > keyed in any way. There is NO GROUND present by any means...no wire
> > > ground, no BX cable nor conduit.
> >
>
> > 1) Is the receptacle keyed in any way to ensure proper hot and neutral
> with
> > mating plug connections?;
MOST ALL OF MY MESSAGES TO AMPS@ SAID CLEARLY... NO KEY, NO KEY, NO KEY.
NO MARK ABOUT WHICH IS HOT.
> > 2) Is the neutral absolutely floating above all grounded and grounding
> > conductors (e.g, a water pipe or water-fed room radiator)? That of
course
> > assumes piping is even grounded in Thailand. Or, is neutral simply a
> > floating return for the hot (which in reality would make it another hot
> > conductor). Even though the receptacle has no ground reference, is
> neutral
> > grounded/earthed at the service entrance or at some point upstream from
> the
> > utility provider?
WE HAVE ALL PLASTIC WATER PIPES AND THAILAND DOES NOT NEED HEAT RADIATORS.
YES, THE NEUTRAL IS JUST A FLOATING RETURN FOR THE HOT. THAT IS WHY I AM
ASKING ALL THIS RE AMPS PLUGGED INTO THIS SYSTEM.
NEUTRAL HAS NO CONNECTION TO EARTH GROUND, NONE, NONE NONE. AS I SAID
BEFORE, NONE.
COME ON, BRIGHT GUYS, READ MY MESSAGES AND HELP ME, 73, CHARLY
>
>
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