Mains Tester screwdriver

[PJK]

Hi I am hoping for some advice and to see if anyone is aware of this issue.

I was using a mains 240volt mains tester screwdriver ( the clear type, no battery, you just put your finger on the end cap to see if the screwdriver lights up, indicating 240v present). I was getting an indication on the earth wire of a light switch. When connected to the back box earth terminal the RCD did not trip and the RCD is working correctly. I used a Meger1552 to test the cables insulation and tested between all lines, switch wires and earth, no problems indicated. I tested the voltage reading on the earthwire and it was nil. I rewired the switch to the ceiling rose (it was easy to do) with new cable. The earth of the new cable also read an indication on the mains tester screwdriver yet it was definitely not shorting and was not connected at either end etc., Seems I was getting some sort of feedback through my body which caused the screwdriver to light up. Full PIR done on the installation and everything is fine.
Any comments would be welcome.

 

[Bromd123]

Best advice i can give is dont use the testing screw drivers as they are bobbins!

Get yourself a set of test lamps with a digital display

 

[Risteard]

A phase tester is the most dangerous "tool" there is. Get rid of it and use an approved voltage indicator. There is absolutely no place for phase testers. They should be banned and their manufacture should be illegal.

 

[supasparxs]

A phase tester is the most dangerous "tool" there is. Get rid of it and use an approved voltage indicator. There is absolutely no place for phase testers. They should be banned and their manufacture should be illegal.

I totally agree
I also think that neon screwdrivers shouild not be included in a proffesional screwdriver sets

I think it gives a false approval to the DIYer or apprentices

Richard

 

[Risteard]

I totally agree
I also think that neon screwdrivers shouild not be included in a proffesional screwdriver sets

I think it gives a false approval to the DIYer or apprentices

Richard

Indeed. That is one of the biggest problems - and not to single out any particular make of insulated screwdrivers as many reputable brands seem to include them.

I notice they tend to advise not using them as a screwdriver - it would be more sensible advising that they aren't used as phase testers!

 

[mjvor]

I agree with the above comments that neon screwdrivers are not reliable indicators. They can also be dangerous. If the resistor in series with the neon inside is damaged or shorted or gets wet then you'll get 240v on your pinky.

I'm guessing PJK that it lit up on the incoming cpc. That would usually mean that the other end was not connected to earth or is broken somewhere. It will pick up a voltage by capacitance from the adjacent live conductors. A volt meter will still show 0V. Did you do a continuity test from the MET? Is the supply end connected to earth?

 

[ian.settle1]

I agree with the above comments that neon screwdrivers are not reliable indicators. They can also be dangerous. If the resistor in series with the neon inside is damaged or shorted or gets wet then you'll get 240v on your pinky.

I'm guessing PJK that it lit up on the incoming cpc. That would usually mean that the other end was not connected to earth or is broken somewhere. It will pick up a voltage by capacitance from the adjacent live conductors. A volt meter will still show 0V. Did you do a continuity test from the MET? Is the supply end connected to earth?

As I found out about 30 years ago if you also get hold of anything connected to earth then you also get a belt as well.

 

[Guest123]

I quite often use mine to prove dead......especially on 3P kit!!!

 

[coatek]

Totally agree with all above. My assessor nearly failed me for having one.
What about the non-contact type, happy with it so far or am I being lulled into a false sense of security?

 

[scotsparky]

IMHO a waste of tool box and pocket space i havent and never have owned one. Th touch free voltage indicators are a bit better but mustnt be relyed on there good indication only but before works starts get the proper lamps and proving unit out and check!!!!

 

[AA410]

Great fun with wet hands

 

[Bromd123]

IMHO a waste of tool box and pocket space i havent and never have owned one. Th touch free voltage indicators are a bit better but mustnt be relyed on there good indication only but before works starts get the proper lamps and proving unit out and check!!!!

couldn't agree more when i was a lad helping my uncle he gave me one of they volt stick none touch voltage checkers, unbeknownes to me the battery was dead and i got a right belt!! he did it on purpose to teach me a lesson lol or so hhe said. I reckon he just didnt want my dad to lay him out at the time lol

 

[mjvor]

The continental view is that fuses can blow and give you a false indication of a safe conductor. The Steinel design has a high internal impedance so a fault in the instrument can't cause a short. If you use a fused instrument then you absolutley have to prove the instrument afterwards on a known source. I think you should on any instrument to prove dead.

An HSE guy told me once that the Steinel is effectively GS38 so long as it has the small tips and good leads etc. The true GS38 with the fuses in the probes gives you total protection in case you get a short across faulty leads eg if your lead scrapes against some sharp earthed metal and the probe is on a live terminal.

I had a boss once who nearly blew his face off by connecting an AVO across 415V busbars on the ammeter scale.

Stay safe. You're a long time dead. It feels like longer if you're maimed. Happy new year.

 

[Risteard]

You MUST prove the voltage indicator before and after testing for voltage anyway so I can't see the problem.

 

[PJK]

I agree with the above comments that neon screwdrivers are not reliable indicators. They can also be dangerous. If the resistor in series with the neon inside is damaged or shorted or gets wet then you'll get 240v on your pinky.

I'm guessing PJK that it lit up on the incoming cpc. That would usually mean that the other end was not connected to earth or is broken somewhere. It will pick up a voltage by capacitance from the adjacent live conductors. A volt meter will still show 0V. Did you do a continuity test from the MET? Is the supply end connected to earth?

Thanks for that,n you have explained the false reading issue clearly. Full PIR conducted and earth continuity to MET is fine.
Cheers