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pushrod

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Yes i know they should be put in the bin. Anyway if they work by a high resistance letting only a tiny current flow through you, can anyone explain to me why i got these results when i touched it onto the connections on a wall light that was switched on.

phase - red glow (as expected)

neutral - no light ( i thought all the current would still be there? Has all the pd been dropped across the bulb - so even though there is a current there is no energy?)

CPC - v dim glow ????

When i put a voltage tester (measuring 3.5V to 230V) across each pair i got a voltage registering on all three pairs. Can the CPC be at a higher potential than the neutral?
 
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Spudnik

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  • #2
The cpc could be picking up stray voltage from the cable as its closer to the line than the neutral if its T&E.
 
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Tiger

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  • #3
Yes i know they should be put in the bin. Anyway if they work by a high resistance letting only a tiny current flow through you, can anyone explain to me why i got these results when i touched it onto the connections on a wall light that was switched on.

phase - red glow (as expected)

neutral - no light ( i thought all the current would still be there? Has all the pd been dropped across the bulb - so even though there is a current there is no energy?)

CPC - v dim glow ????

When i put a voltage tester (measuring 3.5V to 230V) across each pair i got a voltage registering on all three pairs. Can the CPC be at a higher potential than the neutral?
Need i say more, if you put it on the other side of a closed light switch it will glow:D
 
P

pushrod

  • Thread Starter Thread Starter
  • #4
The cpc could be picking up stray voltage from the cable as its closer to the line than the neutral if its T&E.
Yes it is T&E - does that mean the cpc is at a higher potential than the neutral?

Need i say more, if you put it on the other side of a closed light switch it will glow:D
tried that - it didn't!
 
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T

Tiger

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  • #5
youve got a good one then ive had one glowing from my finger before. i would take no notice from a neon at all
 
S

Spudnik

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  • #6
Tend to agree here.

Whilst they are fine to see if a cable may be live, one should never use it to prove dead.
 
W

WarrenG

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  • #7
Or checking for continuity of a lamp............apart from that they are pretty dangerous used for anything else.
 
Yes i know they should be put in the bin. Anyway if they work by a high resistance letting only a tiny current flow through you, can anyone explain to me why i got these results when i touched it onto the connections on a wall light that was switched on.

phase - red glow (as expected)

neutral - no light ( i thought all the current would still be there? Has all the pd been dropped across the bulb - so even though there is a current there is no energy?)

CPC - v dim glow ????

When i put a voltage tester (measuring 3.5V to 230V) across each pair i got a voltage registering on all three pairs. Can the CPC be at a higher potential than the neutral?
Your neutral IS effectively AT earth potential or should be or else your light wouldn't be lit!!
If you go to consumer unit and disconnect the neutral then test it you will see that NOW it IS live and the light isn't lit!
(not suggesting that you should try this at home,leaving a live wire dangling!!!)
Your voltage on the cpc-yes it is closer to the live and guess what it has NO insulation. What we test when we meggar,is insulation resistance test,,how much, if you like electricity can escape,this can increase if there is moisture or even paint on the cables,and breakdown increases with age and use.This is why we should actually DO the insulation resistance test,rather than simply writing >200 every time.
As for phase tester screwdrivers,mine lights up when I touch the door handle on my living room.
 
W

wattsup

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  • #9
Anyone can make a neon light by rubbing on trousers Vic Reeves style on shooting stars...neons are for making holes in wood a bit like a bradall, thats all
 
S

sivoodoo

  • Thread Starter Thread Starter
  • #10
Are we talking those crappy little screwdriver things with the neons in or votsticks, I had a cheapo voltstick from toolstation, lit up whatever i touched, are there better ones on the market that you can trust?
 
S

Spudnik

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  • #11
The fluke Volt alerts are good as they have sound and light, but they should only be used for indication and not for proving dead.

I can't stress that enough!!!!!!!!
 
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