Casing gives current

[Ron Reaugh]

Do you use a walloutlet with or without ground? Always use an earthed
walloutlet for your computer. About the danger, the shock is not deadly
but can be anoying.

DANGEROUSLY FALSE. You can't be certain.

In this case you have also lost your failsafe, when
your PSU will die, you will be out of light, but again not deadly.

Ignore this guy as he is DANGEROUS.

 

[Ron Reaugh]

Something potentially fatal to you and your computer is wrong. This 'not
deadly' nonesense is dead wrong. Get this fixed by someone who knows what
they're doing. I don't mean to flame or belittle anyone but this is a very
dangerous situation and it should be resolved. Voltages in your power
supply can KILL you.

YES and this Chris van Bladel guy is demonstrating depraved indifference or
overt incompetence.

 

[Ron Reaugh]

I am not insulted or felling flamed by your remark or that of Papa. I
wpould like to clear up one or two things. I am a professional and
diplomated??? system and display repair person.

You are totally UNPROFESSIONAL and obviously 'diplomated' in illiteracy and
lunacy.

I have been electified

Was that at your sanity hearing?

by differant DC and AC currents and voltage from a wide range of
computerapliances.

And obviously that has taken its full consequence on a damaging portion of
your intellect.

I have to admit, confessing this doesn't give me and
credits with you guys or improve your conidance in me because it was in
all cases my fault and i shoud have taken beter care.

Go on disability.

The voltages in computers and monitors aren't deadly, but it hurts like
hell and doesn't feel great.

Have you had any training in Afghanistan?

 

[Ron Reaugh]

I think he meant grouding oneself BEFORE touching AGAIN but not DURING
the touching. It was poorly written (dangerously so).

One is NOT ALLOWED that kind of error or poor writing in such a matter.

 

[David Maynard]

I am not insulted or felling flamed by your remark or that of Papa. I
wpould like to clear up one or two things. I am a professional and
diplomated??? system and display repair person. I have been electified
by differant DC and AC currents and voltage from a wide range of
computerapliances. I have to admit, confessing this doesn't give me and
credits with you guys or improve your conidance in me because it was in
all cases my fault and i shoud have taken beter care.

And there are cases where people have survived direct lightning hits to
their person but that doesn't mean it's 'harmless' and that walking around
in the middle of a lightning storm with a 30 foot metal pole in your hands
is a good idea.

A.C. line voltages can, and do, kill people. Doesn't happen every time but
unless russian roulette is your cup of tea then it's wiser to not put the
barrel to your head regardless of how many times you've pulled the trigger
on an empty cylinder.

The voltages in computers and monitors aren't deadly, but it hurts like
hell and doesn't feel great. The OP has a problem with the grounding of
his computercase, this voltage isn't deadly only anoying, it can however
damage his computer.

Dangerous nonsense.

The fact that he can 'feel' it means he's not dealing with 'safe' voltages.

Because much people don't understand electronics, volts and currents
they overreact and scream murder and death as soon as the hear the word
current. This will automaticly panic the OP and people will feer
currents and volts even more.

http://www.statefarm.com/consumer/vhouse/articles/childout.htm

"Statistics on Fatal Electrical Injuries in the United States

Household Wiring 18%
Large Appliances 17%
Small Appliances 16%
....
86 percent of the reported injuries involved children 1- to 4-years-old..."

Because THEY haven't yet learned to not stick their fingers into what you
say "aren't deadly" voltages.

 

[Ron Cook]

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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.

If you touch the case or hard disk _with one hand_ and keep your other hand
(or any other part of your body) from contact with _anything_, do you still
feel the current ?

Does the feeling "tingle"? Does it continue for as long as your hand touches
the device ?

If the above is true then *immediately* call a professional electrician and
have the mains wiring evaluated, and repaired if necessary, before using
the computer again.

Under no circumstance allow both hands to come in contact with devices
powered from the mains.

If the electrical shock is very short and ends almost immediately, you may
be experiencing a discharge of static electricity.

That can be painful but should not cause harm to a _properly_ earthed
computer.

- --
Ron n1zhi
(e-mail address removed)
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[Papa]

One final comment, and I'm outta here. Those that insist that nothing
harmful can happen when there is a known electrical event "tingling" your
fingers are most likely the same ones who insist that seat belts are silly -
and I read about one of those fatalities in the paper every day.

 

[T Shadow]

I think people are missing the point. The computer case is supposed to be
grounded. If you can feel electricity in the case the ground is not
absorbing it. That means the house is not wired correctly or at least their
is no ground wire to catch faulty appliances(computer). If the house is
incorrectly wired their is a potentiall fire hazzard. If you think house
fires caused by electrical problem are not likey you don't watch the news.

 

[Freddie Clark]

I think people are missing the point. The computer case is supposed to be
grounded. If you can feel electricity in the case the ground is not
absorbing it. That means the house is not wired correctly or at least their
is no ground wire to catch faulty appliances(computer). If the house is
incorrectly wired their is a potentiall fire hazzard. If you think house
fires caused by electrical problem are not likey you don't watch the news.

Well we have now heard from all you "developed country" Guys.
I live in Thailand, Most houses built here have no Earth at all. So anyone
hooking up a metal case here will feel a "Tingling sensation" if they touch
the case (do it with the back of your hand always, as if higher currents are
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
they are coupled with sufficient current (over .2 Amps) then death can
result, It is the current that kills not the voltage. I solved the problem
in my house by running my own earth to a 12 foot Copper rod and using UK
standard plugs. You can buy Current limiting Devices here (which I believe
are now required by law in all new buildings in the UK), however they
generally fail regularly due to the generally poor wiring. As an aside my
neighbour complained of a tingly feeling while walking barefoot on his lawn
after watering it!!.
Notwithstanding the above, Electricity can and often does bite you hard when
you dont expect it. I think the OP had a common earthing problem, that would
probably not be dangerous in any way, but I would call in someone who knows
the difference between a Fluke and a Megga and get it sorted out.

regards
Freddie

 

[David Maynard]

I think people are missing the point. The computer case is supposed to be
grounded. If you can feel electricity in the case the ground is not
absorbing it. That means the house is not wired correctly or at least their
is no ground wire to catch faulty appliances(computer).

Or the case isn't grounded, or it's not plugged into a 3 prong outlet, or
the power strip it's plugged into is faulty.

There can be a multitude of reasons.

But you're right that they should make sure the house wiring is correct.

 

[David Maynard]

Well we have now heard from all you "developed country" Guys.
I live in Thailand, Most houses built here have no Earth at all. So anyone
hooking up a metal case here will feel a "Tingling sensation" if they touch
the case (do it with the back of your hand always, as if higher currents are
present it will cause you to snatch your hand away). Contrary to many
posters beliefs Standard line voltages of 120/240 are NOT fatal.

And that statement is WRONG.

However if
they are coupled with sufficient current (over .2 Amps) then death can
result, It is the current that kills not the voltage.

It's not 'fatal' but death can result. Nice distinction.

And, no, I didn't miss the 'current' comment, which is true and we all know
it. But unless you've got 120/240 wall outlets current limited to 2 ma then
it's a 'distinction' of no practical consequence as a 120/240 mains
connection is quite capable of delivering enough 'current' to kill someone.

 

[larrymoencurly]

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?

I would have the wall outlets checked with a plug-in tester sold by
Radio Shack and hardware stores. It has several lights that glow to
indicate things like faulty ground. If the tester indicates that the
AC outlet is OK, I would replace the power cord because it may have a
broken ground connection inside.

It's dangerous to check for shock by feeling the computer because the
current could flow through your lung diaphram or heart and stop your
breathing or your blood flow. So you may want to get a plug-in ground
fault circuit interrupter, about $12 from Home Depot (stocked near the
outdoor extension cords) because while it won't eliminate the shock,
it will shut off the current if the shock is dangerous (but press its
"test" button because GFCIs sometimes fail), even if the AC outlet is
ungrounded. To test for electrical leakage, you'll need a voltage
meter and read both AC and DC volts (reading the wrong type of current
will give a reading of zero).

A lot of PSUs will give a harmless shock if plugged into an ungrounded
AC outlet because they have some small capacitors connected between
the case and high voltage to filter out interference. The capacitors
are low enough in value to prevent dangerous currents, but capacitors
can fail, and there are also other factors can put high voltage on the
case.

 

[Ron Cook]

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Hash: SHA1

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.

I don't recall you being asked under what condition(s) this sensation is
observed.

Are you touching the case / power supply / hard disk using just one hand
with the other in a pocket ?

Do you have nearby any radio transmitting equipment (Amateur Radio) which is
transmitting at the time you feel this ?

Are you located near a commercial / non-commercial broadcast antenna array ?


- --
Ron n1zhi
(e-mail address removed)
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[Ron Cook]

-----BEGIN PGP SIGNED MESSAGE-----
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I would have the wall outlets checked with a plug-in tester sold by
Radio Shack and hardware stores. It has several lights that glow to
indicate things like faulty ground. If the tester indicates that the
AC outlet is OK, I would replace the power cord because it may have a
broken ground connection inside.

The OP appears to be in Germany. If the mains service used is within a U.S.
compound the tester you mentioned would probably be fine.

If the service is from the European standard (220 VAC, as I recall) such a
tester may or may not be available.

I'd recommend that the OP acquire a good digital multimeter (3.5 digit
resolution would be enough) and test the outlet to which the computer is
connected.

Unless the user has the knowledge and is qualified to do further
investigation on his / her own, I would suggest contacting a professional
electrician.

It's dangerous to check for shock by feeling the computer because the
current could flow through your lung diaphram or heart and stop your
breathing or your blood flow. So you may want to get a plug-in ground
fault circuit interrupter, about $12 from Home Depot (stocked near the
outdoor extension cords) because while it won't eliminate the shock,
it will shut off the current if the shock is dangerous (but press its
"test" button because GFCIs sometimes fail), even if the AC outlet is
ungrounded. To test for electrical leakage, you'll need a voltage
meter and read both AC and DC volts (reading the wrong type of current
will give a reading of zero).

A GFCI (Ground Fault Circuit Interrupter) - whether installed in the circuit
breaker panel, as a duplex outlet, or an external device - depends upon a
correctly-wired and third-wire-grounded electrical circuit, and ultimately
on a correctly earthed electrical service.

Whether the GFCI functionality works at all with a non-grounded circuit may
be open to debate but it's not an option I'd care to test.

A lot of PSUs will give a harmless shock if plugged into an ungrounded
AC outlet because they have some small capacitors connected between
the case and high voltage to filter out interference. The capacitors
are low enough in value to prevent dangerous currents, but capacitors
can fail, and there are also other factors can put high voltage on the
case.

The issue here is that *NEVER* should one feel *ANY* electrical current when
touching with one hand the metal of a correctly-grounded, installed, and
designed appliance.

A cause may be open to discussion: improper wiring, poorly-designed
circuits, radio-frequency currents, among other items.

It should not occur.


- --
Ron n1zhi
(e-mail address removed)
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[Mr. Jones]

In message <[email protected]> on Wed, 22 Sep 2004

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.

</lurk>

Am I the only one to have noticed that the OP has not posted back? One
can only hope he hasn't tried the suggestions of the "not fatal"
posters with tragic results!

While it's true that the normal voltages inside a computer case are
not dangerous so long as the power supply is not open or defective,
(which, BTW, is NOT true for the inside of CRT monitors) the fact that
you can "feel a slight current" indicates that something is wrong,
possibly exposing you to dangerous line voltage.

120/240 VAC power lines most certainly CAN and DO produce sufficient
current to kill, frequently through cardiac arrest when the current
flows through the heart and interferes with its own electrical
signals. And even if you aren't electrocuted, the risk of a possibly
fatal electrical fire is high.

This needs to be checked out right away.

<lurk>

 

[T Shadow]

Well we have now heard from all you "developed country" Guys.
I live in Thailand, Most houses built here have no Earth at all. So anyone
hooking up a metal case here will feel a "Tingling sensation" if they touch
the case (do it with the back of your hand always, as if higher currents are
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
they are coupled with sufficient current (over .2 Amps) then death can
result, It is the current that kills not the voltage. I solved the problem
in my house by running my own earth to a 12 foot Copper rod and using UK
standard plugs. You can buy Current limiting Devices here (which I believe
are now required by law in all new buildings in the UK), however they
generally fail regularly due to the generally poor wiring. As an aside my
neighbour complained of a tingly feeling while walking barefoot on his lawn
after watering it!!.
Notwithstanding the above, Electricity can and often does bite you hard when
you dont expect it. I think the OP had a common earthing problem, that would
probably not be dangerous in any way, but I would call in someone who knows
the difference between a Fluke and a Megga and get it sorted out.

regards
Freddie

My step brother would disagree with you if he were alive to do so. He was
killed working on a well pump. It's possible his wife turned it on while he
was working on it but still it proves beyond a doubt that house current can
kill you.

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 half truth of current killing not voltage comes from the fact that some
high voltage sources do not make suffecient power to kill. Your house wiring
does not have this limitation. You can put both index fingers on the
terminals of a 600amp 12 volt car battery but don't try it on 15amp house
current.

The point is if your wiring is not correct you are at risk of having a house
fire. If you can sleep at night not knowing its right thats o.k. Others may
want to fix theirs.

 

[T Shadow]

House wiring is a parallel technology. The problem does not have to be in
the computer. In my first post I stated that the circuit had ground wires
connected at the outlets but they were not actually connected to ground.
Under this circumstance anything connected to the circuit that was leaking
current would show up on all of the outlets.

This will be my last post on the subject. The problem can not be determined
by email/news group. The op obviously doen't know anything about electriciy.
Someone qualified has to look at the actual circumstance. Yes the odds of
electrocution are vey low. The odds of a fire are still low but much higher
than electrocution. The house I live in was built when house wiring was high
tech. I've worked on enough house to see how screwed up they can be.

It's not a matter of did I fire five shots or six. More like 1 in
10thousand/100thousand/million. The less you know about your wiring the
higher the odds. When you go to bed tonight and every night ask yourself, do
you feel lucky PUNK!

 

[Freddie Clark]

And that statement is WRONG.

No it is not WRONG
Put it in Context. There must be sufficient Current to cause a fatality.
Even
here in Thailand you can buy a GFI box and (if you have an earth system)
Limit the current to non-lethal figures.
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.

It's not 'fatal' but death can result. Nice distinction.

And, no, I didn't miss the 'current' comment, which is true and we all know
it. But unless you've got 120/240 wall outlets current limited to 2 ma then
it's a 'distinction' of no practical consequence as a 120/240 mains
connection is quite capable of delivering enough 'current' to kill

someone.
SNIP

 

[Ron Reaugh]

"Standard line voltages of 120/240 are NOT fatal

Standard line voltage is POTENTIALLY lethal...END of story.

 

[larrymoencurly]

The OP appears to be in Germany. If the mains service used is within a U.S.
compound the tester you mentioned would probably be fine.

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'd recommend that the OP acquire a good digital multimeter (3.5 digit
resolution would be enough) and test the outlet to which the computer is
connected.

Unless the user has the knowledge and is qualified to do further
investigation on his / her own, I would suggest contacting a
professional electrician.

A GFCI (Ground Fault Circuit Interrupter) - whether installed
in the circuit breaker panel, as a duplex outlet, or an external
device - depends upon a correctly-wired and third-wire-grounded
electrical circuit, and ultimately on a correctly earthed
electrical service.

Whether the GFCI functionality works at all with a non-grounded
circuit may be open to debate but it's not an option I'd care to test.

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?