Can someone give me a good technical description of there workings, I was told its an interview question for a job I'm applying for . I searched on the net but keep coming up with blanks.

If it's what I am thinking about....small screwdriver fitted with a resistor and a neon lamp in the handle mains passes through blade, resistor and neon before going through you to ground .......really unreliable and not recommended for electrical work......not a lot of use as a screwdriver generally

cheapand dirty, i only have one as it came free in a st of decent drivers.

but as above they basically connect you into the circuit which illuminates a neon

They're the work of the devil. I'm an electrical engineer, and there's no way i'd trust my life to one of those things.

Are we taliking about the ones that you stick the blade into the live terminal (just before the flash and waking up in A&E) ?

I had one of these a few years ago, read the instructions, said "Fu...rget that!!" and binned it !! I wonder if the HSE know about these being on open sale?

I reckon it might be something a bit more technical than you think guys. If it's those cheapo death trap style ones then it's not really a good question for an interview is it.

Would it maybe one of the 'No Contact' style ones where you place it on or near an electrical source?? I have one here.

If it's one of the cheap and nasty things, it just whacks a Huuuuge resistor in line with a neon. Your body conducts the mains current to earth, to make the neon light up. The resistor means that only a tiny current passes through you, so it doesn't hurt.

Anything else, I've never come across....

Phil

I wonder just how many people blindly trust their lives to a cheapo resistor probably made in a chinese sweat shop out of two bent pins, a length of plastic tube and the tin foil from a stick of wrigleys gum?

I agree!!

We used to have these at work for 115v - 440v work

http://cgi.ebay.co.uk/WIBRE-2-PRONG-VOLTAGE-TESTER-FOR-AC-AND-DC-110-750-VOLT_W0QQitemZ7534638186QQcategoryZ40004QQcmdZViewItem

I would never use them. There are stories of people using them with the cable around there neck and suffering burns from damaged cable. Even seen pictures of a bloke who had used one end to scratch his head whilst the other was still in the fuse panel.

I think everyones description is right. JRHartleys one is I think what happens in reality, my dads an electrical engineer and even he wont use one unless he really as to. As a screwdriver they are pants to, just to weak and I have snapped a couple trying to use one as a screwdriver.

I find these screw drivers the perfect size for meddling around with my favourit chocolate block connectors. (realising Ive just offended every electrician in the thread I will just back out slowly now ,) heres another weird thing, when I used to ran a marine tank if I put the tip of the screw driver in the tank water it would light up the led, can anyone explain this, was my alkaline salt water acting as a battery or something?

It indicated that your water was at least 100v above ground. Probably didn't have any current behind it, though, or you would've died every time you touched it!

Probably leaky insulation on the heater or pump.

Phil

maybe its one of them magic pen things as i call them

the no contact flashy end things

excellent things they are too. work on megnetic fields given off by current passing through a conductor

maybe its one of them magic pen things as i call them

the no contact flashy end things

excellent things they are too. work on megnetic fields given off by current passing through a conductor

Thats what I was talking about Bengie. I've got one here, never used it though - Don't trust it.

I find these screw drivers the perfect size for meddling around with my favourit chocolate block connectors. (realising Ive just offended every electrician in the thread I will just back out slowly now ,) heres another weird thing, when I used to ran a marine tank if I put the tip of the screw driver in the tank water it would light up the led, can anyone explain this, was my alkaline salt water acting as a battery or something?

Galvanic Action?? :P

I have just come back from lunch and met our shift foreman going home..in his hand he had a....Guess what?................Mains phase tester..when I told him about this thread he is said he is now going to ask SWMBO to try it.!

So whats the proper safe way to test? I use my trusty multi meter myself, and have no qualms about doing so (despite the sharp points on the probes)

So whats the proper safe way to test? I use my trusty multi meter myself, and have no qualms about doing so (despite the sharp points on the probes)

Use a set of test lamps with leads complient to GS38, then test then on a proving unit or known live source and finally on the terminals you are testing again.

This is assuming you are testing to isolate a supply?

These are what I use:

www.pat-training.co.uk/martindale_gs38_voltage_indicator.htm

Cheers for the responses guys, it is the type of one I was referring to. A friend did the same interview before with the company and told me they asked him that and about wiring a plug :eek: . I dunno whats going on with interviewing techniques over here but I see it as them testing you to see how you'll react to situation.

I have used one a number of times at home, I was always a bit wary of the bulb being blown and not showing a live cable. Due to them being fairly common place in tool shops I didn't realise they were that dangerous (to be honest I have used mine a good few times at home, and always use it on something live to ensure the bulb is working first).

Are they really that dangerous ? Is it mainly because people are unsure about the resistors in them ?

I think I better start using the multimeter instead

So whats the proper safe way to test? I use my trusty multi meter myself, and have no qualms about doing so (despite the sharp points on the probes)

I work on systems upto 33000 Volt, we use a Trolex Dead Line Checker, get anywhere near a live electrical connection (AC only) and it lights up like a christmas tree, no need to actually touch the live conductor. The next step before touching the circuit is to strap the live connection to earth, if this can't be done on the switchgear itself then we use an insulated rod that has the tip strapped to earth.

What is fun is useing phasing sticks to check phase rotation on a 3 phase system, two bits of plastic rod in your hands and you touch two live contacts. I've been doing it years but it still seems odd working on ive 11000 and 33000V systems.

Cheers

Lee

Actually you know it depends the quality of the material that it matters..if you buy one of those really good quality ones you'll never (pretty much) have any risk of causing self-harm, i've used them quite a lot and I've had no problems.

Then again, I'll leave it to the pros to decide, I'm a sound engineer, not electrical. I haven't had problems so I base my thoughts on that

All those I have seen use a neon then a resistor that limits the current that passes through your body. If the resistor goes short circuit the only thing that wiil keep you alive is the clothes you are wearing and the type of floor you are standing on.

As little as 30 milliamps passing through your body is enough to kill you.

Cheers

Lee

It has to be my good old fluke multimeter every time, I would never trust a "volt stick" or a neon to prove a circuit, what if the neon or resistor go open circuit after being dropped/kicked/generally abused?

Granted, I dont work on anything mad like 11+kv but a 600VDC inverter bus is more than enough to straighten the curlies.