Neon screwdriver earth?

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I've just had the debate with a collegue with him saying neon screwdrivers are not reliable up ladders coz theres no earth path or something.
I said that when using a neon screwdriver, I act as the earth for it, so doesn't matter if I jump up in the air the neon will still light up.
Who's right???
 
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Theoretically, if you jump when using a neon screwdriver, the neon should go out - In practice, it doesn't - It just dims.. If you floated for a few seconds or so, I reckon you would notice a difference.

At the end of the day, you should not be using these as a qualified spark anyway, and should NEVER be relying on them!
 
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The route to earth from the end of the neon screwdriver is mainly capacitive coupling between the surface area of the holder and the surrounding grounded area.

But there are so many variables affecting the brightness of the neon that they must NEVER be trusted. A dark neon may indicate a dead circuit or it may indicate the person has a very high skin resistance and due to small body a very low capacitive coupling to ground while the circuit is live.
 
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on the other hand traditional meters can fail to indicate live because you don't have the other end of them hooked up to a good neutral/earth.

The best thing to do would be to have a wander lead from the MET with you all the time but that isn't very practical.
 
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Hypothetical situation - an average punter opens a plastic lamp bayonet fitting - they want to check to see if it is live. The average householder will not have a contactless, approved voltage indicator but may well have a multimeter or neon. The occupier thinks that he has isolated the supply but for whatever reason, when investigating the fault both prongs of the fitting are phase potential. His multimeter will indicate zero across the two prongs, thus giving a false sense of security. A neon will glow. Which is the safer to use and recommend? And it will glow even if you are up a ladder (albeit difficult to see in bright sunlight).
 
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Come on, hand them in :rolleyes:


neonamnesty.jpg
 
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bernardgreen said:
But there are so many variables affecting the brightness of the neon that they must NEVER be trusted. A dark neon may indicate a dead circuit or it may indicate the person has a very high skin resistance and due to small body a very low capacitive coupling to ground while the circuit is live.

If a neon is tested on a known live conductor and illuminates and is then immediately tested on another conductor and does not illuminate, why is it not safe to conclude that the second conductor is not live?
 
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Remember a neon can illuminate when the voltage is very low and the voltage between two terminals cannot always be determined.
 
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"Hypothetical situation - an average punter opens a plastic lamp bayonet fitting - they want to check to see if it is live. The average householder will not have a contactless, approved voltage indicator but may well have a multimeter or neon. The occupier thinks that he has isolated the supply but for whatever reason, when investigating the fault both prongs of the fitting are phase potential. His multimeter will indicate zero across the two prongs, thus giving a false sense of security. A neon will glow. Which is the safer to use and recommend? And it will glow even if you are up a ladder (albeit difficult to see in bright sunlight)."

No serious answer then - so by default the point stands.


Ebee - Presumably you have no qualms about grasping the insulated tails of a live circuit and the associated induced voltage in your body? Presumably you have no qualms about brushing up against the face of a CRT when on and inducing an electrostaic charge of circa 40KV in your body?

The prongs of a neon are physically separated and conatined within an inert gas. This is then connected in series with a very high resistor. The risk of use by a non technical householder are infinitessimally small compared to the risk of non use and the possibility of working on a live circuit.

Only a fool would condemn the use of neon screwdrivers without properly considering the risks in doing so.

Regards
 
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