Elctrical test screwdriver's neon light gets brighter.

[tryitandsee]

I have never noticed this before and now not sure if my wiring is faulty.

When touching the live terminal with screwdriver, behind plug socket. with finger on the end of screwdriver and then touch the stainless steel kitchen sink, the neon light gets brighter. When not touching sink, neon goes back duller again!

I tried it, out of interest, at my neighbours house and theirs is the same. Is this normal

 

[rebuke]

When you touch the sink, you have a much better connection to earth, so more current can flow causing the neon to glow brighter, so it's expected.

Note however that this shows a very good reason why neon screwdrivers are a bad idea - if you had no connection to earth whatsoever (e.g. you had a very well insulating floor, or were wearing very good rubber soled shoes etc), then your neon screwdriver wouldn't glow, so you might think something is dead when it isn't. My (and many others) normal recommendation for a neon screwdriver is to throw it away...

Edit to explain why you have a better connection earth: Assuming your incoming water main is correctly bonded, and there is no plastic pipework between it and the sink, then you will get a better earth connection through the metal pipework, than just through the floor.

 

[tryitandsee]

Thanks for that explanation, that's cleared that one up. I had never encountered that before and it was totally confusing me. I was exchanging a central heating time clock, with slightly different wiring set up (typical) and was leaning over the kitchen sink to do it, hence the 'light up' of neon.

Thinking about your last statement, the floor to this kitchen was a solid concrete floor (old out shed)..........you live and learn, thanks again

 

[Adam_151]

I was exchanging a central heating time clock, with slightly different wiring set up (typical) and was leaning over the kitchen sink to do it, hence the 'light up' of neon.

If you must work live... Its even more inadviseable to do it while leaning agaisnt earthed metal!!

 

[Taylortwocities]

Throw the nasty thing away!

Untitled

• Taylortwocities
• 11 Feb 2009
• 20

 

[RF Lighting]

That picture looks familiar

 

[Taylortwocities]

Picture courtesy RF

 

[ricicle]

If you are touching the neon screwdriver on a live conductor with one hand and something ' earthy' with the other then a percentage of the current being used to light the neon is flowing across your heart. What if the resistor were to go short-circuit.......

BIN IT

 

[nrgserv]

If you are touching the neon screwdriver on a live conductor with one hand and something ' earthy' with the other then a percentage of the current being used to light the neon is flowing across your heart. What if the resistor were to go short-circuit.......

BIN IT

yep!
bet me to it!
240 volt straight up the finger end!
have one and never used it.

 

[ban-all-sheds]

240 volt straight up the finger end!

≈180V.

 

[tryitandsee]

Point well and truly taken, mind you the occasional bolt across the heart probably keeps it 'alert'. it doesn't get much excitement nowadays

I must admit to the other most second dangerous habit I've acquired, in that I've reached the age of having to have reading glasses and can never find the bloody things when I start doing these things. Prodding about almost in the dark

 

[nrgserv]

240 volt straight up the finger end!

≈180V.

not that im gonna short a resistor out to try this, but how do you know its 180v?
what does the double wiggle bit indicate? (and where's the button for it on the keyboard, as i dont seem to have it!)

 

[BS3036]

not that im gonna short a resistor out to try this, but how do you know its 180v?
what does the double wiggle bit indicate? (and where's the button for it on the keyboard, as i dont seem to have it!)

Neon drops some volts across it. ≈ means approximately. Copy and paste from somewhere else.

 

[ban-all-sheds]

Yup - neons need about 80V to strike and once struck drop about 60V.

You can use them instead of triacs in dimmer switches...

The series resistor is there to limit the current through the neon because they exhibit negative resistance, and unless limited they'll draw more and more current until they pop.

 

[robertito]

Is there anyone reading this who's ever had an electric shock from a neon screwdriver ?