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If I want to improvise an antistatic strap then could I simple wrap
some wire around my wrist (or my ankle) and then attach the other end
of the wire to the case of the PC I am working on?

Isn't that all an antistatic strap (like this one shown here) really
is?

http://www.maplin.co.uk/images/Full/32142i0.jpg

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Franklin wrote:

> If I want to improvise an antistatic strap then could I simple wrap
> some wire around my wrist (or my ankle) and then attach the other end
> of the wire to the case of the PC I am working on?
>
> Isn't that all an antistatic strap (like this one shown here) really
> is?
>
> http://www.maplin.co.uk/images/Full/32142i0.jpg

A wire will work fairly well especially if you sweat a lot. The idea
of the wide bank is that is makes contact with a lot of skin, minimizing
the electrical resistance. Practically speaking, just about anything
will work.

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On Mon, 23 May 2005 12:47:38 +0100, Franklin
<no_thanks@mail.com> wrote:

>If I want to improvise an antistatic strap then could I simple wrap
>some wire around my wrist (or my ankle) and then attach the other end
>of the wire to the case of the PC I am working on?
>
>Isn't that all an antistatic strap (like this one shown here) really
>is?
>
>http://www.maplin.co.uk/images/Full/32142i0.jpg

yes that would work if the case remains grounded. If it
doesn't, simply being at same potential as the case doesn't
necessarily save a part if you and the case are still at a
higher potential than ground... once you take parts out you
can still have a charge flow though the part to a (closer to
earth) contact with something.

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On Mon, 23 May 2005 12:47:38 +0100, Franklin <no_thanks@mail.com> had
a flock of green cheek conures squawk out:

>If I want to improvise an antistatic strap then could I simple wrap
>some wire around my wrist (or my ankle) and then attach the other end
>of the wire to the case of the PC I am working on?
>
>Isn't that all an antistatic strap (like this one shown here) really
>is?
>
>http://www.maplin.co.uk/images/Full/32142i0.jpg

No, an antistatic wrist strap also has a resister in it to prevent you
from electrocuting yourself if you touch a high voltage wire.

Stephen


--

Archived from groups: uk.comp.misc,alt.comp.hardware,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

> If I want to improvise an antistatic strap then could I simple wrap
> some wire around my wrist (or my ankle) and then attach the other end
> of the wire to the case of the PC I am working on?

Why not just wear a tinfoil hat? Less restrictive of your movements.

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Franklin wrote:

> If I want to improvise an antistatic strap then could I simple wrap
> some wire around my wrist (or my ankle) and then attach the other end
> of the wire to the case of the PC I am working on?
>
> Isn't that all an antistatic strap (like this one shown here) really
> is?
>
> http://www.maplin.co.uk/images/Full/32142i0.jpg

No. A strap provides a high impedance path to ground, not a dead
short. I believe some inductance is involved as well.

Archived from groups: uk.comp.misc,alt.comp.hardware,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

i unplug the unit from power,
and just touch the case before
grabbing anything else.

never had a problem.

Archived from groups: alt.comp.hardware.homebuilt (More info?)

On Mon, 23 May 2005 14:04:14 GMT, Stephen
<stephen2002{NOSPAM}@lurker.homeip.net> wrote:

>On Mon, 23 May 2005 12:47:38 +0100, Franklin <no_thanks@mail.com> had
>a flock of green cheek conures squawk out:
>
>>If I want to improvise an antistatic strap then could I simple wrap
>>some wire around my wrist (or my ankle) and then attach the other end
>>of the wire to the case of the PC I am working on?
>>
>>Isn't that all an antistatic strap (like this one shown here) really
>>is?
>>
>>http://www.maplin.co.uk/images/Full/32142i0.jpg
>
>No, an antistatic wrist strap also has a resister in it to prevent you
>from electrocuting yourself if you touch a high voltage wire.
>
>Stephen


Yeah, but if you're just working on a grounded case with no power, the
chances of you zapping yourself to death are pretty small

Plug your computer into one of those cheap switched extension strips
and turn off the power. Case grounded, zero juice.

Verify case ground with your ohmmeter.

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~ Avery Anderson~ wrote:
> i unplug the unit from power,
> and just touch the case before
> grabbing anything else.
>
> never had a problem.

It's never been quite clear whether one should completely unplug the
unit. If it's plugged in (while switched off at the mains), there's
still an earth connection bonding everything. If you unplug, the
equipment starts to float (voltage-wise, that is :-) ) which could
potentially cause problems if the operator is grounded.

--
Please use the corrected version of the address below for replies.
Replies to the header address will be junked, as will mail from
various domains listed at www.scottsonline.org.uk
Mike Scott Harlow Essex England.(unet -a-t- scottsonline.org.uk)

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Mike Scott <usenet.9@spam.stopper.scottsonline.org.uk> wrote in
news:VjBke.19355$sE4.1696@newsfe3-gui.ntli.net:

> If it's plugged in (while switched off at the mains), there's
> still an earth connection bonding everything.

....and there's still standby power on the system if it's an ATX or
later motherboard system.

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Kinell <w@invalid.jp> wrote in news:Xns96607EA659C8Bkxxx@
194.168.222.124:

> while switched off at the mains

Belay my previous, missed that bit.

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In article <VjBke.19355$sE4.1696@newsfe3-gui.ntli.net>,
Mike Scott <usenet.9@spam.stopper.scottsonline.org.uk> wrote:
>~ Avery Anderson~ wrote:
>> i unplug the unit from power,
>> and just touch the case before
>> grabbing anything else.
>>
>> never had a problem.
>
>It's never been quite clear whether one should completely unplug the
>unit. If it's plugged in (while switched off at the mains), there's
>still an earth connection bonding everything. If you unplug, the
>equipment starts to float (voltage-wise, that is :-) ) which could
>potentially cause problems if the operator is grounded.
>
>--

There is live voltage on the mobo whenever a modern PC is plugged into
the wall. A dropped tool could short something out.



--
a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.

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Mike Scott <usenet.9@spam.stopper.scottsonline.org.uk> writes:
>~ Avery Anderson~ wrote:

>> i unplug the unit from power,
>> and just touch the case before
>> grabbing anything else.
>> never had a problem.

>It's never been quite clear whether one should completely unplug the
>unit. If it's plugged in (while switched off at the mains), there's
>still an earth connection bonding everything. If you unplug, the
>equipment starts to float (voltage-wise, that is :-) ) which could
>potentially cause problems if the operator is grounded.

True, but from the standpoint of why one is using a grounding strap,
what you need to protect the ESD-sensitive devices is a way to assure
that everything being used is at the *same* potential. (This is the
reason that workers maintaining live high-voltage power lines will connect
the wire to their bucket: assuring that no potential difference
exists between them and the equipment they're working with.)

Note that merely touching a charge sink (such as the case) doesn't
guarantee anything about potential differences once you break that
connection. That's an advantage of using an antistatic strap: you
have both hands free while assuring that your body is at the same
potential as the sink.

And your comment "If it's plugged in (while switched off at
the mains)" has a pair of unstated assumptions:

1) The grounding ("earth" ) conductor is in fact working as
it should, and
2) No other device on that branch circuit is leaking energy
into the supposedly dead current-carrying conductors.

Far too many occupancies (especially older ones) weren't designed
with grounding conductors, and too many that have been retrofitted
have grounding systems that are not properly implemented. A common
example is the use of a cold water pipe as the grounding conductor.
With the rise in popularity of PVC pipes, consider the probability
that at some point in the future a plumber will replace a part of the
metallic water pipes with PVC...leaving the allegedly grounding
conductors floating, probably well above actual ground potential.

And even if one of the current-carrying conductors is grounded (note
the difference between groundING and groundED conductors) an
all-too-common problem is failure of the bonding between the grounded
conductor and the grounding point at the service panel. (Note: I'm
not very familiar with UK wiring standards or terminology.) Thus if
you have leakage from some other energy source (example: a computer and
printer fed from different mains but connected by a cable) you could have
some interesting consequences even if the mains feeding the other
device are disconnected.

Joe Morris

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On Tue, 24 May 2005 08:10:29 GMT, Mike Scott
<usenet.9@spam.stopper.scottsonline.org.uk> wrote:

>~ Avery Anderson~ wrote:
>> i unplug the unit from power,
>> and just touch the case before
>> grabbing anything else.
>>
>> never had a problem.
>
>It's never been quite clear whether one should completely unplug the
>unit. If it's plugged in (while switched off at the mains), there's
>still an earth connection bonding everything. If you unplug, the
>equipment starts to float (voltage-wise, that is :-) ) which could
>potentially cause problems if the operator is grounded.

The system should either be turned off via a power switch
(main cutoff) on the back of the power supply which leaves
the system grounded, or unplugged from AC entirely and then
the earth-grounded user should touch a ground point on the
system first, to ensure that system ground is at similar
potential as user who is earth grounded.

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Kinell wrote:

>
> ...and there's still standby power on the system if it's an ATX or
> later motherboard system.

Press the powerbutton once more when the unit is unplugged. This way the
system will try to powerup and "drain" or "use up" the voltage left in
the PSU.

And as for toughing the case with your wrist, thats the way