Why did my voltage tester just explode?

[Jeansie]

Hi,

I'm new to this forum, but it seemed like a good place to find out why my voltage tester (screwdriver type) basically just exploded when I tested it on a mains voltage supply (back-box of a fused spur switch). I was trying to check whether the fused spur is part of the main loop (it looks like it is - it has 2 twin and earth cables feeding into one of the "input" set of the live, neutral and earth terminals, and one twin and earth feeding from the output to a junction box which isn't feeding anything)
Hopefully you can see from the attachment what it did to the voltage tester

None of the power supply has failed for any of the sockets in the house

If anyone has any ideas why this happened please let me know.

Thanks

 

[GLENNSPARK]

it probably happened because you went short circuit with `it`....
and they are an `it` n all.......
how dare you come in here and start waving such a nasty piece of work in front of us....lol..
glad you did actually as this is clear evidence of just how grotesque these artefacts to incompetance really are....
throw em, break em, smash em ......wherever you find em.....

 

[Jeansie]

So... I touched it on something I shoudn't have whilst it was still in contact with the live terminal? I've been using it to test the means voltage this way for weeks and this hasn't happened before. What did I do wrong this time?

 

[electric will]

You've probably hit the side of the tip on neutral or earth terminal while the end was on the live.
can you take a closer picture of just the very tip?

 

[grantr37]

Shorted, lucky you never got eye injury, throw it in the bin/recycling and wouldn't buy another one.......you need some proper test equipment, and a volt stick.....would you like a volt stick for your toolbelt? I can post you one in the mail for free , I have a few spare....

 

[Deleted member 9648]

On some accessories the earth bar is right in front of the live terminal....so an uninsulated tip of a screwdriver can short out the live and earth.....it didnt 'explode'...you caused a dead short between L and E. If you look at the tip of your screwdriver you can see the two contact points.Potentially several hundred amps would have flowed through such a short instantaneously.
Get yourself an approved set of voltage probes with insulated tips.

If the fuse/mcb/RCD or whatever didnt operate I'd be checking the correct type and rating for the circuit is installed at the CU.

 

[Jeansie]

Cheers for all your replies.

Electric Will: See attached picture

Grantr: Are the volt sticks the non-contact ones which either glow/buzz if they are near a live feed

wirepuller: I think the entire mains is on the same circuit and nothing has stopped working, so does this mean the fuse must still be fine? The house has one of the old style plug in fuse boxes - what rating should the mains (sockets) fuse be?

 

[MDJ]

what is that thing you have there? much safer to use one of these Metrel TEK7100 Non Contact Voltstick :rofl:

 

[shagbite]

these things use your body to complete a circuit, jeansie. you're putting your faith and wellbeing in the resistor that is fitted in the screwdriver. bin it and get a volt stick.

 

[i=p/u]

no offence you dont know what your talking about , ive been there now looking back on my old posts, but can see your learning or egarness to learn somewhere in above posts... get yourself a proper voltage tester..£30 if you plan to work as electrician i just gave one away too or you could of had it.

we all have neons and are very careful and know when to use them. which some/most people will say never as they arnt 100% safe

 

[topcat]

If you had the tip on the live a lot of new socket plates have the earth very close and I think as others have said you shorted it out I would get a 2 pole tester or a non contact volt stick at least a bit safer.

 

[i=p/u]

some volt sticks are rated from 110v to 230v so effectively they saying might not pick up 90v.

 

[MDJ]

I'd never trust a volt stick, however if you do use one get 2, and stick them both near the cable, you may find one won't light at all, very unreliable, my post above was just for fun, please buy a proper tester.

 

[bigbaddave]

I am rather worried that you say "Tested it" this sounds remarkably like a drunking ebay purchase which you have been eager to play with when it arrives a week later from China

I have loads of them.. The only thing I think these are good for is the terminals on junction box's

Voltage tester.... The only thing between you and electric shock is a resistor...

 

[i=p/u]

mines a ck one and cost 3.50... but all chat about these being bad for health and they seem to be everywhere for sale even the pound shop with connectors and pvc tape all in one bag

 

[Geordie Spark]

it probably happened because you went short circuit with `it`....
and they are an `it` n all.......
how dare you come in here and start waving such a nasty piece of work in front of us....lol..
glad you did actually as this is clear evidence of just how grotesque these artefacts to incompetance really are....
throw em, break em, smash em ......wherever you find em.....

I'm impressed with that ... I really am !!!

 

[Geordie Spark]

So... I touched it on something I shoudn't have whilst it was still in contact with the live terminal? I've been using it to test the means voltage this way for weeks and this hasn't happened before. What did I do wrong this time?

What you did wrong this time was exactly what you did wrong last time - you used a neon screwdriver - the difference is last time you got away with it & this time you didn't !!

Neon screwdrivers should not be used for anything more technical than stirring tea or poking holes in plasterboard !!

Get yourself a proper tool for the job and learn how to use it.

 

[bigbaddave]

mines a ck one and cost 3.50... but all chat about these being bad for health and they seem to be everywhere for sale even the pound shop with connectors and pvc tape all in one bag

How much do they sell for in there as a pack?

 

[rmdes]

I always get those things free, what a load of crap, I use mine as a knocking driver about all it's good for, they don't even meet the spec for testing equipment as they have a large exposed tip. Stop buying crap from the pound shop and get yourself some decent tools

 

[shagbite]

What you did wrong this time was exactly what you did wrong last time - you used a neon screwdriver - the difference is last time you got away with it & this time you didn't !!

Neon screwdrivers should not be used for anything more technical than stirring tea

or poking holes in plasterboard !!

Get yourself a proper tool for the job and learn how to use it.

i hope you didn't pick mine up by mistake geordie. i use it for scratching my arse!

 

[SJD]

I was trying to check whether the fused spur is part of the main loop (it looks like it is - it has 2 twin and earth cables feeding into one of the "input" set of the live, neutral and earth terminals, and one twin and earth feeding from the output to a junction box which isn't feeding anything)

Just to add, the fact that there are two cables into the FCU "input" does not necessarily mean it is on the ring (loop), it could be a spur that someone has then taken a second spur from, don't assume what is already there is correctly connected ...

 

[Geordie Spark]

Just to add, the fact that there are two cables into the FCU "input" does not necessarily mean it is on the ring (loop), it could be a spur that someone has then taken a second spur from, don't assume what is already there is correctly connected ...

Aye ..... I always think that if you're to assume anything, assume that it's wrong until you can prove otherwise.

 

[Jeansie]

No, what I meant was that there are 2 fused spur switches which don't appear to be doing anything...so I wanted to know why they are there (hence testing them - not the voltage tester)

 

[Jeansie]

Just to add, the fact that there are two cables into the FCU "input" does not necessarily mean it is on the ring (loop), it could be a spur that someone has then taken a second spur from, don't assume what is already there is correctly connected ...

It then feeds to the next socket, which then feeds somewhere else, so I thought it's likely to be part of the loop. Should you take a spur from a spur, and if so, how many times can you do that?

 

[shagbite]

It then feeds to the next socket, which then feeds somewhere else, so I thought it's likely to be part of the loop.

Should you take a spur from a spur, and if so, how many times can you do that?

you can, as long as they're appropriately fused. if they're not fused, then you're only allowed one spur from one socket.

 

[Steve_P]

There's a diagram in the back of the BGB that tells you all about that Jeansie.

 

[Geordie Spark]

There's a diagram in the back of the BGB that tells you all about that Jeansie.

I'm not sure that Jeansie knows what the BGB is never mind have one.

 

[Steve_P]

I'm not sure that Jeansie knows what the BGB is never mind have one.

That's why I mentioned it mate. Surely there is a point where well meaning help runs the risk of giving someone misleading advice through only having partial facts?

 

[Geordie Spark]

That's why I mentioned it mate. Surely there is a point where well meaning help runs the risk of giving someone misleading advice through only having partial facts?

I agree.

That very thing has been discussed and argued on this board many times.

 

[Steve_P]

I agree.

That very thing has been discussed and argued on this board many times.

Uh huh. I'm all in favour of well meaning advice, I've seen it stop people in their tracks before they get fried but tbh, I do have concerns when I see a shorted neon screwdriver that the owner asks why it happened then gets advice on spurs. Jeansie, this is no way intended to be a dig at you but really if you don't understand the basics please get a spark to help.