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WORD OF WARNING


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Hello guys just had a powerful shock from a static flock applicator just touched the wire that had came off the rail which was NOT ON ,just useing it as a earth .I was holding the botton in at the same time and BANG right up my arm ;;so watch out !!!!

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Matters not , it will bite you either way , you are acting as the earth path ,

 

Indeed. With the friction between the fibres and the plastic components it's perfectly feasible you may be generating well over 10000 volts. Fortunately the current will be very low, but the voltage will be quite sufficient to stimulate your muscle fibres and nerve neurons!!

 

Jeff

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I think the Green Scene applicator produces about 15000 volts in it's charging circuit to stimulate the fibres ,

when you have finished you need to unscrew the lid then holding the clip by it cable lower it into the pot and

short it out on the centre pin , with a homemade one just short the sieve to the pin in the scenery , you get

a goodspark from either . Both with the power off of course .

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Maybe I'll carry one of them instead of a taser...

 

In that case, I'll grovel to our armourer tomorrow, and convert one to static grass applicators - cheaper than buying one !

 

But will I have to go thro' all the 'spiel' before I start grass laying !

 

Brian R

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They work on the same principle as the electronic fly zappers (you can make one using one of these), so the chances of a significant 'belt' are high. The 'works' include a supply capacitor, so the thing is still 'live' even when switched off.

 

As always, great care is advised when using tools.

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I've not used a static-grass applicator yet, though I plan to buy one for the new layout.

 

If you are getting sparks during discharge then the voltage may be even higher than stated previously. A rough guide is 30000V for each cm of spark! So plenty of potential (excuse the pun) for a nice shock or too!

 

And - don't tell the police...can you imagine them confronting Raul Moat..."Hands up you multiple killer, or I'll zap you with my grass applicator!!"

 

Jeff

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To quote an old saw - "Its volts that jolts, but mills that kills". In other words high voltage at very low current will give you a 'shock', but will do you no harm, but at comparatvely lower voltages (e.g. 240 volts), higher current (e.g. a few amps) may well prove fatal. The trick in both cases is to make sure you are never acting as the earth. The circuit needs to be firmly earthed through some medium other than your body!

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  • 4 weeks later...

A few amps will definetly be dangerous! The mills in the saying refers to milliamps - a few milliamps can prove fatal if suffered long enough.. All that is required is sufficient current to interfere with the brain's communication with vital muscles (heart or diaphram - for example) for a sufficient length of time. I assume that a pacemaker would be just as, if not more susceptible.

 

Just an observation!

 

Cheers

 

Ian

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I would hope that folks with pacemakers are advised to keep well away from such devices. I knew a guy who worked for one of the first pacemaker manufacturers, and he recounted several tales of patients who had unfortunately exposed themselves to something capable of generating a high voltage, with terminal consequences. One example was a guy who went out to use a camera and a heavy duty flashgun in a torrential downpour...

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The same effect can be had from the CDUs used for turnout switching.

They can pack quite a punch.

The procedure is to discharge any such device before touching any part that may contain juice.

Bernard

 

Hi

 

It was for this reason that I had a relay wired to discharge the CDU when shutting the layout down as I got caught out once and it wasn't pleasant.

 

Cheers

 

Paul

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A few amps will definetly be dangerous! The mills in the saying refers to milliamps - a few milliamps can prove fatal if suffered long enough.. All that is required is sufficient current to interfere with the brain's communication with vital muscles (heart or diaphram - for example) for a sufficient length of time. I assume that a pacemaker would be just as, if not more susceptible.

 

Just an observation!

 

Cheers

 

Ian

 

Quite right Ian. I once had a 1300V shock (later measured the discharge current at 2mA). It threw me across my laboratory. Fortunately I was only touching the supply with one hand and the earth path bypassed my chest. If I'd had both hands on the supply I'd have been dead for 32 years by now.

 

Lucky to survive that one - anything approaching amps, even at a much lower voltage, would be lethal (I haven't seen the technical spec for applicators, but if they provide 10kV+, the current must be in the microamp range. Shocking, but "safe").

 

Jeff

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A few amps will definetly be dangerous! The mills in the saying refers to milliamps - a few milliamps can prove fatal if suffered long enough.. All that is required is sufficient current to interfere with the brain's communication with vital muscles (heart or diaphram - for example) for a sufficient length of time. I assume that a pacemaker would be just as, if not more susceptible.

 

Just an observation!

 

Cheers

 

Ian

A few amps through the body is totally lethal! An extract from a NEBOSH (Safety Qualification) book:

0-1 milliamps - undetected by the body

1-15 milliamps - threshold of cramp

15-30 millamps - cramp, breathing difficult, limit of tolerance

30-50 milliamps - longer times will lead to fibrillation

50-500 milliamps - loss of consciousness, fibrillation

 

This is why RCDs should operate at about 30 millamps after 30 milliseconds!

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