ABC Inventors - electrical safety device

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Did anybody see the New Inventors last night? Can anyone guess how
"Protex Switching Technology" works? The inventor said something about
detecting voltage changes, and using the neutral as the reference.

See http://www.abc.net.au/newinventors/txt/s1356442.htm


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Re: ABC Inventors - electrical safety device


On Thu, 05 May 2005 08:45:01 +1000, Franc Zabkar

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Hi Franc

Yes I saw the show and was going to post almost exactly what you have
said.

He also claimed it was pretty cheap ie around a dollar to build.

Frankly, I am a bit sceptical of claims that it would do anything more
than an RCD and/or a sensitive circuit breaker, especially as you got
virtually no information as to how the thing works at all. I would be
happy to be proved wrong.

Dave Goldfinch


Re: ABC Inventors - electrical safety device



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In the text Wayne said "It works" but the description is very vague on
details and seems to not understand 'Double Insulated'.
He says it can be built into the device. Well if the switch is in the
hair dryer in the water how does it keep the EXCESS electricity out of
the water?
--
John G

Wot's Your Real Problem?

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Re: ABC Inventors - electrical safety device


put finger to keyboard and composed:

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My impression of the man was that he was either short on
understanding, overawed by the occasion, or just deliberately vague.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Re: ABC Inventors - electrical safety device


put finger to keyboard and composed:

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The ABC URL states that the device could be made waterproof by
encapsulating it. Assuming there are no exposed parts upstream of the
safety device, then the hair dryer should not "leak" electricity.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Re: ABC Inventors - electrical safety device



"Franc Zabkar"

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**   Exactly -  the inspiration and whole idea of the invention is to
instantly isolate a Class 2 hair dryer or shaver that lands in the bath tub
or wash basin.





..............     Phil



Re: ABC Inventors - electrical safety device



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double insulated .. well the level of insulation isnt  relevant, he was
probably trying to think of what doubling the insulation could do....

(my wires are double insulated - two layers of cling wrap !)



Re: ABC Inventors - electrical safety device



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Are you joking?
DOUBE INSULATED is a construction standard for electrical devices.
--
John G

Wot's Your Real Problem?



Re: ABC Inventors - electrical safety device


On Thu, 05 May 2005 08:45:01 +1000, Franc Zabkar

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It seems to be a device to be built into or retrofitted into an
appliance, as is implied in the video, and as such, the only way I can
think it would work is to "learn" the typical current/voltage usage
patterns of the device its connected to - and if there is any sudden
change in these patterns- (that 'looks' consistent with human contact
or "hazardous" leakage for example?) that seems suss, then it shuts
off the power.

If this is the case, (its in the appliance) then surely it would
provide no protection for the cord, plug etc of that appliance, and
these probably need to be protected a lot more than the innards of the
appliance, as cords are so easily damaged, and often touched by the
consumer ?   for that matter - if his magic device is INSIDE the
hairdryer - and the dryer is then thrown into the bathwater - it might
very well do a great job of cutting the power to the dryer's
internals, but how is it going to stop the current still flowing down
the cord and into his device ?
(Put a massive short across the active/neutral to make the house fuse
blow maybe ? :)

I also find it strange his implication that appliances with 2 pin
plugs "seem to be unable to work effectively with an RCD compared to 3
pin ones".  As I see it - an RCD will work just as well with 2 pin as
3 to protect a human body from electric shock, as long as you have an
earth connection, (ie: the ground you are standing on) and if you
didnt have a ground connection to your body when you touched the
active lead, you aren't going to get a shock anyway, unless you grab
both active and neutral.

I didn't see the process where the panel interviewed him on the device
- and there are no details even remotely on how it works, either on
his website or the URL you gave above.  In fact the whole site seems
to totally avoid the theory of operation and instead give tons of
vague"consumer' type information about how wonderful it is - and will
save the world etc etc.

also, how many cases would there be of people accidentally coming into
contact with both active and neutral connections *simultaneously* in
domestic situations ?  remember that unless you grab both of them at
the same time, (within the trip time of the RCD) then the one you
touch first - will set the RCD off and stop the current flow anyway)



Re: ABC Inventors - electrical safety device



"KLR"


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**  Imagine a small kiddie picking up one of those mini two pin female plugs
as used on many items like shavers, small audio and VCRs and DVDs. The
kiddie then decides to put the plug in its mouth while the other end is
plugged in and live.

The RCD will not trip.


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**  Not at all -  when standing on a wood or carpet floor there is not
enough earth leakage to trip an RCD.

   One has be in contact with an earthed object to do that.


BTW

 I agree with your other comments about the Inventors device.


...........   Phil





Re: ABC Inventors - electrical safety device


You're right Phil.

Phil Allison wrote:

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Re: ABC Inventors - electrical safety device



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Correct, he said such on the show when asked.



Re: ABC Inventors - electrical safety device


On Thu, 05 May 2005 13:51:18 +1000, Terry Collins

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Then why go to the trouble of building it into your appliances when
you could mould it into a universal plug? In fact the inventor agreed
that the device could be incorporated into the GPO. The ABC URL goes
on to say that "Protex is an electrical safety switch that can be
installed at the manufacturing level into new household appliances
(toasters, kettles, hair dryers) or into a homes electrical power box
or switch board." This says to me that it's a two-wire device
(remember the toaster demo), and that it's probably nothing more than
an automatically resettable RCD, despite the inventor's statement that
it senses voltage. The switching element would be mechanical, as it is
claimed that "it does not use power until a fault is detected, meaning
it does not generate heat". A triac would get quite hot if it were
asked to deliver 2000W to a kettle, for example. I suspect that
latching could be provided by an SCR or a transistor pair. Maybe one
end of the solenoid coil is connected to neutral and the other end to
the gate of an SCR via a zener diode. Perhaps that's what the inventor
meant by "sensing voltage". You'd probably need a diode bridge and a
capacitor as well. But can all that be made for a dollar?


- Franc Zabkar
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Please remove one 's' from my address when replying by email.

Re: ABC Inventors - electrical safety device



"Franc Zabkar"

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 **  See my  "two cents worth" .

Doing that does not allow connection to metalwork in a Class 2 appliance.


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**  But it looks like he has not tried it.


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**  I prefer not to assume the inventor is a liar.




...........    Phil




Re: ABC Inventors - electrical safety device


to keyboard and composed:

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But how do you make a device like that for $1? And how could you
distinguish leakage from the load changes that result from normal
usage? Furthermore, the ABC URL states that "Protex is an electrical
safety switch that can be installed ... into a homes electrical power
box or switch board". The inventor also agreed that it could be fitted
inside a GPO. This means that one device could be protecting several
appliances.

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Unfortunately the panel were not knowledgeable in this particular
field, so they were unable to ask pertinent questions. The inventor's
website is annoying in that it requires you to log in, and is heavily
reliant on flash. Whenever I see a Macromedia intro, I am immediately
suspicious of the quality of the content.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Re: ABC Inventors - electrical safety device




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you cant do that for $1.50

You could do it for $1000.



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true.



  for that matter - if his magic device is INSIDE the
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true, its pointless  . they wont build the hair dryer to do it.

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He would have tested  two wire hair dryer in a ceramic vanity basin with
plasic pipes.
Do you see any thing for an RCD to detect ??

Now take a three wire hair dryer. There's water between active and earth.
I see an RCD trigger.



The protex is only working because its requiring the third wire in the hair
dryer.

Stick to the RCD and combine the protex into it.

That would make it a  "RCSVD " Residual current or stray voltage device.


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yes, quite correct.


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Yeah he will save the world, but  only if the RCD disappears.

all mass produced things cost $1.50 to make. whats the actual sale price
????



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none at all.

this leads to the result that the protex is not as good an RCD,
you should have RCD's  first and then protex if you still want more
protection.


The  protex may as well be added to the function of  the RCD

RCSVD.. Residual Current Stray Voltage Device.



Re: ABC Inventors - electrical safety device



"Franc Zabkar"
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 **  My two cents worth is this:

The Protex device trips a normally closed latching solenoid switch upon
detection of a significant  AC voltage appearing on the metal case or
internal metal ( non live) parts of the particular Class 2 appliance -  as
measured relative to the neutral wire.  Pretty much,  this makes it a
submersion detector.

Such AC voltage detection - if applied to external metal parts would have to
be via a low value Y2 rated capacitor so not to breach Class 2 requirements.





.............   Phil





Re: ABC Inventors - electrical safety device


I reckon its all a croc of shit. The only way to get electrocuted to death
if you have an RCD, is if you grab a neutral cable in one hand and an active
cable in another while standing on an insulated floor. The current has to
pass through the heart or through the brain to kill you. If you read some
stories with regard to electric chairs, you will find that it is actually
quite difficult to kill someone with electricity.

Even a baby that sticks a live two pin plug in its mouth will be ok. Might
just get a big shock but certainly not death. Even then the child will have
to be insulated from earth.


Same goes with a dryer in a bath tub. A bath tub is often connected with
metal drain pipes to earth. So the RCD will go off if the current is not
balanced between active and neutral. If it is balanced enough to not set the
RCD off, then there is little risk to the occupant in the bath tub.





Re: ABC Inventors - electrical safety device



"Heywood Jablome"
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**  If you read accounts of accidental electrocutions -  you will find it is
absurdly easy to die.

Do you remember the one where the 3 y.o girl died when using a hairdryer
while sitting on the back step -  when her older brother threw small bucket
of water onto her  ???


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**  You have proof of this ????


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 **  You have proof of this ????


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 **  A carpet floor will do that.


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**  This last one has GOT to be a subject for the Mythbusters .



...........    Phil








Re: ABC Inventors - electrical safety device



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Yes. But how do you get both of them into a bath?
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