Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)



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On 01/10/2017 12:27, Cursitor Doom wrote:
Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)



You are assuming a conductive skin, maybe OK for Tesla coil type high
frequency AC voltages. The current path will be through blood and other
bodily fluids.

On 01/10/2017 12:27, Cursitor Doom wrote:
Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

Perhaps you can measure, with a low, safe voltage, current entering the
hands and that passing from one hand to the other with your contraption.

Please do report back with your findings, however I suspect once current
enters the body little will come back out through skin and be bypassed
by your wigget.

BICBW

What you need is what this guy wears! I doubt it take much current though:
https://www.youtube.com/watch?v=9tzga6qAaBA

On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
coalesced the vapors of human experience into a
viable and meaningful comprehension...

Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

Ah, "Safe Tea" was a play on words was it?

I visualised having to hold a mug of tea in one hand while I prodded
about with the other.

I remember being taught that eating or drinking whilst sustaining a
shock put you in danger of choking to death, not advice I have heeded
to any great extent.


--

Graham.
%Profound_observation%

On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:


Perhaps you can measure, with a low, safe voltage, current entering the
hands and that passing from one hand to the other with your contraption.

"Contraption" indeed! Hardly a contraption by any definition.


Please do report back with your findings, however I suspect once current
enters the body little will come back out through skin and be bypassed
by your wigget.


Must admit I hadn't considered skin resistance as you and newsy
mentioned. HOWEVER I do have some conductive electrode lube I've not had
cause to use for a different project I was working on. Be interesting to
try your test with and without the lube; it might just make that critical
difference.






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What you need is what this guy wears! I doubt it take much current
though: https://www.youtube.com/watch?v=9tzga6qAaBA

This is the powerline work I like:

https://www.youtube.com/watch?v=Mfz1YrpMbBg

--
Davey.

On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:


What you need is what this guy wears! I doubt it take much current
though:
https://www.youtube.com/watch?v=9tzga6qAaBA


Presumably those two cables are at the same potential and *in* phase WRT
each other or that suit is going to burn up in a heartbeat!



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protocols constitutes acceptance of this condition.

On 01/10/17 12:27, Cursitor Doom wrote:
Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

You really need a couple of these joined together (and earthed?).
https://www.scobiesdirect.com/Produc...in+Mail+Gloves

--

Jeff

On Sun, 01 Oct 2017 15:41:07 +0100, Jeff Layman wrote:


You really need a couple of these joined together (and earthed?).
https://www.scobiesdirect.com/Produc...in+Mail+Gloves

I see where you're coming from here, but gloves like that rob you of the
sensitivity you need for much investigative troubleshooting. And yes,
they will need to be earthed *if* you're not using an isolation
transformer to power up the DUT.



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protocols constitutes acceptance of this condition.

On 01/10/17 16:37, Cursitor Doom wrote:
On Sun, 01 Oct 2017 15:41:07 +0100, Jeff Layman wrote:


You really need a couple of these joined together (and earthed?).
https://www.scobiesdirect.com/Produc...in+Mail+Gloves

I see where you're coming from here, but gloves like that rob you of the
sensitivity you need for much investigative troubleshooting. And yes,
they will need to be earthed *if* you're not using an isolation
transformer to power up the DUT.

It was a suggestion half made in jest. But one thing they would stop -
which wrist bracelets would not - are arc burns down unprotected skin.
These are absolute buggers to heal, as the underlying tissue is
superheated and killed.

Many people only consider the shock problem, but the burn can be a
serious issue:
https://en.wikipedia.org/wiki/Electrical_burn

--

Jeff

On Sun, 01 Oct 2017 16:47:40 +0100, Jeff Layman wrote:

It was a suggestion half made in jest. But one thing they would stop -
which wrist bracelets would not - are arc burns down unprotected skin.
These are absolute buggers to heal, as the underlying tissue is
superheated and killed.

I did refine the concept following a bit of feedback from early in the
thread. Electrode lube will improve conductivity and reduce any skin
burning. And burning takes time, even if only a little time. So a
worthwhile addition would be something to instantly cut the power in the
event of the detection of a fault current. Something easily re-settable
perhaps (if you're planning on making a habit of getting electrocuted).

Many people only consider the shock problem, but the burn can be a
serious issue:
https://en.wikipedia.org/wiki/Electrical_burn

Yeah, but better burned than killed.



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On Sunday, 1 October 2017 12:27:53 UTC+1, Cursitor Doom wrote:
,,, I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable.

I haven't seen any products in Ann Summers marked as VDE tested :-)

Owain

On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
wrote:

Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live.The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

I would have though that for added safety you would need to ground
your connecting wire so it removes the resistance of one wrist and set
of fingers , a wire dragging around is almost bound to snag on
something sometime and pull a hand onto something live that if it were
free would have stayed clear so it doesn't actually sound that
practical. better not to allow any current through in the first place
and wear insulating gloves.

G.Harman

On 01/10/2017 14:34, Cursitor Doom wrote:
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:


Perhaps you can measure, with a low, safe voltage, current entering the
hands and that passing from one hand to the other with your contraption.

"Contraption" indeed! Hardly a contraption by any definition.

Nerve hit?

Please do report back with your findings, however I suspect once current
enters the body little will come back out through skin and be bypassed
by your wigget.


Must admit I hadn't considered skin resistance as you and newsy
mentioned. HOWEVER I do have some conductive electrode lube I've not had
cause to use for a different project I was working on. Be interesting to
try your test with and without the lube; it might just make that critical
difference.

Except getting any conductive lube on one's hand mights create a greater
risk of conduction into your arms.

Perhaps spikes penetrating the skin on wrists? :-)

What might be an idea is to measure voltage across shoulders and pass an
equal and opposite current through the wrists?

You just have to remember to take electrodes off in the right order!

On 01/10/2017 14:43, Cursitor Doom wrote:
On Sun, 01 Oct 2017 14:21:50 +0100, Fredxxx wrote:


What you need is what this guy wears! I doubt it take much current
though:
https://www.youtube.com/watch?v=9tzga6qAaBA


Presumably those two cables are at the same potential and *in* phase WRT
each other or that suit is going to burn up in a heartbeat!

He did say it had fire-resistant fibres, so I guess even if you didn't
survive the suit would.

I understand those cables carry an awful lot of current. Bundles are
commonly used for improved cooling and are easier to handle.

On 01/10/2017 17:04, Cursitor Doom wrote:
On Sun, 01 Oct 2017 16:47:40 +0100, Jeff Layman wrote:

It was a suggestion half made in jest. But one thing they would stop -
which wrist bracelets would not - are arc burns down unprotected skin.
These are absolute buggers to heal, as the underlying tissue is
superheated and killed.

I did refine the concept following a bit of feedback from early in the
thread. Electrode lube will improve conductivity and reduce any skin
burning. And burning takes time, even if only a little time. So a
worthwhile addition would be something to instantly cut the power in the
event of the detection of a fault current. Something easily re-settable
perhaps (if you're planning on making a habit of getting electrocuted).

Many people only consider the shock problem, but the burn can be a
serious issue:
https://en.wikipedia.org/wiki/Electrical_burn

Yeah, but better burned than killed.

Not when you eventually die from your internal burns.

Some survive the initial shock/burn and then go onto die later.

wrote:

On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
wrote:

Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live.The
main thing we need to avoid is suffering a shock where the current passes
through or nearby the heart. This is *most* shocks when you're fiddling
about inside such environments with both hands. I'm proposing to
short-out both wrists using a metallic bracelet on each, tied to one
another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

I would have though that for added safety you would need to ground
your connecting wire so it removes the resistance of one wrist and set
of fingers , a wire dragging around is almost bound to snag on
something sometime and pull a hand onto something live that if it were
free would have stayed clear so it doesn't actually sound that
practical. better not to allow any current through in the first place
and wear insulating gloves.

G.Harman

I would think that the very last thing you would want to be putting in a
high voltage cabinet would be an earthed metal object. You want
personal electrical insulation, flash protection and burn protection.
But, above all, a very clear idea what you want to touch and what you
don't want to touch. And if you are measuring anything as opposed to
just turning it on or off then test prods on long insulated holders.
One at a time fixed in place. And turning things on and off is
probably best done with a long insulated thing.

Main rule I would follow is don't go near them unless you have to and
have a very clear idea what you are going to do and which bit is which.
It it gets to the stage of trying to divert a high voltage from one hand
to the other via an alternative path then you have already lost; and you
certainly don't want it to be a low resistance path.


--

Roger Hayter

On Sun, 01 Oct 2017 18:55:35 +0100, Fredxxx wrote:

Except getting any conductive lube on one's hand mights create a greater
risk of conduction into your arms.

Yes, you would need to ensure the goo remains on the electrodes only.

What might be an idea is to measure voltage across shoulders and pass an
equal and opposite current through the wrists?

You just have to remember to take electrodes off in the right order!

Not quite sure what you're suggesting here, but if it's what I think, it
won't help because in the actual application I have in mind (working on
live switching power supplies) there are all sorts of voltages up to
about 800V present, all capable of supplying enough mills to kill.
I think my idea merits further investigation, so I'll do the testing you
suggested in an earlier post when time permits.


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On Sun, 01 Oct 2017 19:08:22 +0100, Fredxxx wrote:

Not when you eventually die from your internal burns.

Some survive the initial shock/burn and then go onto die later.

I think that scenario typically occurs with extremely high voltage power
lines or prolonged 'low' voltage shocks (such as when you can't let go of
mains live wire due to muscle paralysis).



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Hmm, well, it might restrict the movement a bit I suppose, but I'm sure I've
seen something like it before. The whole issue of course is can you actually
definitely guarantee that the current will all flow where you expect it to.



Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Cursitor Doom" wrote in message
news
Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

On Sunday, 1 October 2017 14:29:55 UTC+1, Graham. wrote:
On Sun, 1 Oct 2017 11:27:51 -0000 (UTC), Cursitor Doom
coalesced the vapors of human experience into a
viable and meaningful comprehension...

Gentlemen,

I've just come up with a very simple idea to massively improve safe-
working in high voltage cabinets where testing has to be done live. In
fact it's so simple there must surely be some flaw in it that I've
overlooked (or there's already some obscure product that covers it). Tell
me what you think.
Firstly, when I say "high voltage cabinets" I'm not necessarily referring
to mains consumer units and whatnot (although this idea is equally valid
for those) I find it easier to visualise (for the sake of getting the
concept across) working on an old analogue TV for example, where you have
all sorts of voltages present, including some highly lethal ones in
excess of 10kV. The main thing we need to avoid is suffering a shock
where the current passes through or nearby the heart. This is *most*
shocks when you're fiddling about inside such environments with both
hands. The standard advice has been "well, keep one hand inside your back
pocket, then" but this means of course you only have one hand to prod
around with which is constricting. I'm proposing to short-out both wrists
using a metallic bracelet on each, tied to one another via a couple of
feet of light, flexible cable. So for example if you're prodding around
with your right hand whilst somehow touching the chassis with your left
and you touch something live, the current will only flow through your
hands and wrists rather than up your arms and across your chest. And
that's all there is to it.
Now, where have I gone wrong? (I must have done somewhere!)

Ah, "Safe Tea" was a play on words was it?

I visualised having to hold a mug of tea in one hand while I prodded
about with the other.

I thought of an administrator working hard drinking tea and talk ******** about something they know nothing about and hence getting put in charge of it a bit like being in charge of glading on buildings.

I can't help but think that linking your wrists together with metak is more like some sort of remote handcuff fetish and more likely to cause accidents by gettign tangled in the cable.

On Mon, 02 Oct 2017 08:36:38 +0100, Brian Gaff wrote:

Hmm, well, it might restrict the movement a bit I suppose, but I'm sure
I've seen something like it before.

You were maybe thinking of one of these, which performs a somewhat
different function: http://tinyurl.com/yclwlnw2




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On Monday, 2 October 2017 11:41:49 UTC+1, Cursitor Doom wrote:
On Mon, 02 Oct 2017 08:36:38 +0100, Brian Gaff wrote:

Hmm, well, it might restrict the movement a bit I suppose, but I'm sure
I've seen something like it before.

You were maybe thinking of one of these, which performs a somewhat
different function: http://tinyurl.com/yclwlnw2

or perhaps this.

http://www.temptationsdirect.co.uk/x...ngs-Cable.html