Casing gives current

[Dee]

present it will cause you to snatch your hand away). Contrary to many
posters beliefs Standard line voltages of 120/240 are NOT fatal. However if

regards
Freddie

I cut some from your "words of wisdom" but have a question - If, as you
claim "120/240 are Not fatal" how come so many people die from
electrocution in homes.

I have even seen at least one suicide where an individual grabbed the
ends of two wires that were plugged into a wall socket - he was dead!
How did this happen if, as you claim it's not fatal?

 

[Ron Reaugh]

Ron Cook <[email protected]> wrote in message

Good point. I mentioned the tester only because some people will kill
themselves if they try to use a meter on a wall outlet.



I used to think that, too, so I tested a few GFCIs without ground
connections, and they all turned off the current when a 10K ohm or so
resistor was inserted between the hot socket and the GFCI's
unconnected ground socket. I looked inside them and found that their
built-in test circuits, which consist of about the same thing, don't
depend on any outside ground protection. Also if GFCIs did require
grounded outlets, how would the GFCIs built into all hairdryers work
because every one I've seen had only a 2-wire plug?

GFCIs work by measuring the two wire circuit. The current over the two
wires must be identical else it interrupts. The theory is that if you drop
the hair dryer in the bathtub them some current is gonna go down the drain.
That being bad and meaning some current in one wire is goin down the drain
and not the other wire then it breaks the circuit.

 

[David Maynard]

No it is not WRONG

Yes, it IS wrong.

Put it in Context. There must be sufficient Current to cause a fatality.

Which a standard 120/240 wall outlet is quite capable of providing, many
times over.

Even
here in Thailand you can buy a GFI box and (if you have an earth system)
Limit the current to non-lethal figures.

That's a wholly different matter than saying "Standard line voltages of
120/240 are NOT fatal."

Perhaps you would be happier if I modified the above statement to read:
"Standard line voltages of 120/240 are NOT fatal unless sufficient current
is also applied".
Although as I added this below, maybe you are just nit-picking.

No, the problem is you NOW make a special case and then retroactively claim
that makes a generic statement about "120/240 line voltages" true. It
doesn't. And even if one accepted that the output side of GFI protected
outlets are 'non fatal' that does not mean that "120/240 line voltages" are.

The generic, most common, situation does not include GFIs on every outlet
and to proclaim that "120/240 line voltages" are inherently 'non fatal" is
irresponsible.

 

[David Maynard]

Good point. I mentioned the tester only because some people will kill
themselves if they try to use a meter on a wall outlet.




I used to think that, too, so I tested a few GFCIs without ground
connections, and they all turned off the current when a 10K ohm or so
resistor was inserted between the hot socket and the GFCI's
unconnected ground socket. I looked inside them and found that their
built-in test circuits, which consist of about the same thing, don't
depend on any outside ground protection. Also if GFCIs did require
grounded outlets, how would the GFCIs built into all hairdryers work
because every one I've seen had only a 2-wire plug?

Actually, a proper GFI doesn't 'depend' on the earth ground for the GFI
function as it operates by sensing a difference in the current flow through
the hot and neutral lines which, under normal operation, should be equal.

There are, however, problems with that theory: inductive, and other 'out of
phase', loads cause false trips during normal operation and that's one
reason why they're not just automatically placed everywhere.

 

[Ron Reaugh]

The generic, most common, situation does not include GFIs on every outlet
and to proclaim that "120/240 line voltages" are inherently 'non fatal" is
irresponsible.

Exactly, to compose any sentence that includes that at its beginning is
IRRESPONSIBLE regardless of what comes after it.

 

[David Maynard]

I cut some from your "words of wisdom" but have a question - If, as you
claim "120/240 are Not fatal" how come so many people die from
electrocution in homes.

I have even seen at least one suicide where an individual grabbed the
ends of two wires that were plugged into a wall socket - he was dead!
How did this happen if, as you claim it's not fatal?

A dead body trumps 'theory'.

 

[Ron Cook]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I used to think that, too, so I tested a few GFCIs without ground
connections, and they all turned off the current when a 10K ohm or so
resistor was inserted between the hot socket and the GFCI's
unconnected ground socket. I looked inside them and found that their
built-in test circuits, which consist of about the same thing, don't
depend on any outside ground protection. Also if GFCIs did require
grounded outlets, how would the GFCIs built into all hairdryers work
because every one I've seen had only a 2-wire plug?

That *is* interesting. It would then seem the GFCI bases its ground
reference against the neutral (white) side of the service. In most U.S.
residential (possibly commercial, as well) electrical wiring the neutral
and third-wire ground are tied together at the service panel(s) anyway.


- --
Ron n1zhi
(e-mail address removed)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.2 (GNU/Linux)

iD8DBQFBV1AQa9fyRcf4bIYRAiqHAKCCAgL7RXvMoB351lQd16tHFh3kKwCfVvN1
g1u/7bYFzh3+gsyjrjtUXJg=
=DYss
-----END PGP SIGNATURE-----

 

[David Besack]

GFCI(Ground Fault Circuit Interupter) was developed to help keep people from

being killed by the power sources you say are not lethal. GFCI requires a
gound to work.

The first thing I thought when I read the original post was a ground
wire must not be present. I am going to take a random guess that either
the computer is plugged into one of those 3-2 prong adapters, negating
the ground, in which case it should be changed immediately. Or there is
a problem with the ground connection in the outlet, which should also be
addressed immediately by a qualified electrician.

 

[PWY]

The first thing I thought when I read the original post was a ground wire
must not be present. I am going to take a random guess that either the
computer is plugged into one of those 3-2 prong adapters, negating the
ground, in which case it should be changed immediately. Or there is a
problem with the ground connection in the outlet, which should also be
addressed immediately by a qualified electrician.

This has been a long ,but at times, an interesting discussion. I suppose
everyone involved must be young by my standards, as no one has mentioned
that older homes, with older wiring, do not have three prong receptacles.
In the 60's, I believe, the code in my state began requiring three prong
receptacles in the kitchen and bathroom.
At some later point the code was changed to require them in all rooms.

PWY

 

[CBFalconer]

.... snip ...

I used to think that, too, so I tested a few GFCIs without ground
connections, and they all turned off the current when a 10K ohm or
so resistor was inserted between the hot socket and the GFCI's
unconnected ground socket. I looked inside them and found that
their built-in test circuits, which consist of about the same
thing, don't depend on any outside ground protection. Also if
GFCIs did require grounded outlets, how would the GFCIs built
into all hairdryers work because every one I've seen had only a
2-wire plug?

They basically work by comparing incoming (on one line) current
with outgoing (on the other line) current. Any imbalance must be
going somewhere, so trip.

 

[Ed Medlin]

They basically work by comparing incoming (on one line) current
with outgoing (on the other line) current. Any imbalance must be
going somewhere, so trip.

We are talking AC here, right........

Ed

 

[Jeffrey Morse]

I feel a slight current when I touch the back of my casing or harddisk when
the system is on. Is this dangerous or damaging for the motherboard/system?
How can I rectify this problem?

thx.

Dangerous, not really. But it indicates bad grounding
from the wall outlet the computer is plugged into, and
that could be potentially damaging to the motherboard/
system. It will probably shorten their life, but more
importantly, a surge suppressor plugged into an
ungrounded outlet (such as in your situation) is
useless at protecting your system from power surges.

 

[Ron Reaugh]

"MAB" <[email protected]> wrote in message

Dangerous, not really.

CLUELESS. It's potentially very dangerous.

But it indicates bad grounding
from the wall outlet the computer is plugged into, and
that could be potentially damaging to the motherboard/
system. It will probably shorten their life, but more
importantly, a surge suppressor plugged into an
ungrounded outlet (such as in your situation) is
useless at protecting your system from power surges.

Actually that is FALSE. A surge supressor will do most of its good even
without a good ground.

 

[Al Smith]

I feel a slight current when I touch the back of my casing or harddisk when

Dangerous, not really. But it indicates bad grounding
from the wall outlet the computer is plugged into, and
that could be potentially damaging to the motherboard/
system. It will probably shorten their life, but more
importantly, a surge suppressor plugged into an
ungrounded outlet (such as in your situation) is
useless at protecting your system from power surges.

Who has grounded wall outlets? I always cut the third prong off
plugs because they are an annoyance. Can't plug a three-prong plug
into a two-slot outlet, can we? May come as a surprise to some
people, but if you cut the third prong off, it makes absolutely no
difference in how your appliances run.

 

[David Maynard]

Who has grounded wall outlets? I always cut the third prong off plugs
because they are an annoyance. Can't plug a three-prong plug into a
two-slot outlet, can we? May come as a surprise to some people, but if
you cut the third prong off, it makes absolutely no difference in how
your appliances run.

No, it doesn't. But you've removed the safety protection. In particular, if
the device depends on a grounded case to protect from an internal (loose or
frayed wire, as but two examples) short (to case) you now have that
potential fault fully exposed to anyone touching the case.

 

[Chris van Bladel]

Dangerous, not really. But it indicates bad grounding
from the wall outlet the computer is plugged into, and
that could be potentially damaging to the motherboard/
system. It will probably shorten their life, but more
importantly, a surge suppressor plugged into an
ungrounded outlet (such as in your situation) is
useless at protecting your system from power surges.

Becarefull, i wrote almost the same, with poorer English, and i nearly
was called a murderer. But like you also state, there is no real danger
in this case for the user but will surely shorten the life of the computer.

Chris

 

[Noozer]

Who has grounded wall outlets? I always cut the third prong off
plugs because they are an annoyance. Can't plug a three-prong plug
into a two-slot outlet, can we? May come as a surprise to some
people, but if you cut the third prong off, it makes absolutely no
difference in how your appliances run.

And you are an idiot...

I guess you also disconnect all the airbags/warning lights in your car, and
the smoke detector in your home, etc. as well.

 

[JAD]

Chris and al

just what planet are you from, or are you just trying to keep a thread
going? Giving advice like that can only mean that you are clueless or
are purposely trying to injure someone. Any ungrounded appliance
120/220 can, in very many situations, be harmful or deadly. It just
takes 1 of a hundred different scenarios to make it happen. My uncle
used to stick his fingers in a socket to see if there was current,
never bothered him, my neighbor however ended up in the hospital by
accidentally doing it. Ripping the third prong off indeed, what do you
live in a 1900's farm house?

 

[Guest]

Who has grounded wall outlets? I always cut the third prong off
plugs because they are an annoyance.

Everybody who doesn't live in a very old house or the Third World.

 

[David Besack]

Who has grounded wall outlets? I always cut the third prong off

plugs because they are an annoyance. Can't plug a three-prong plug
into a two-slot outlet, can we? May come as a surprise to some
people, but if you cut the third prong off, it makes absolutely no
difference in how your appliances run.

You're right, the appliance will run the same. However, if you have an
"unexpected power surplus" in an appliance and there is a ground wire, the
extra power is depleted. If not, and you touch said appliance, you allow
another place for power to flow. Maybe a few mA across your chest will just
be mildly uncomfortable, maybe it will make you shake for the next hour, or
maybe it will stop your heart. That there is some chance of any of those
happening is why ground wires are code.