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Voltage tester?

Discussion in 'The Lounge' started by Zou, Feb 13, 2019.

  1. Zou

    Zou Well-Known Member

    Quick question... I want to replace a ceiling light batten from current bayonet to E27. To feel comfortable enough to attempt this I want to test the voltage before getting up close and personal with the wires and a screwdriver. Is the 'pen' type of non-contact tester sufficient or is it worth going for a multimeter with dual probes? Not going to be doing a lot such work, maybe just the same type of thing in other rooms; never needed one before so I'm leaning toward the pen type as a simpler and slightly cheaper option.

    Can anyone shine a light (sorry!) on the subject please?
  2. Roger_Provins

    Roger_Provins Well-Known Member

    I'd always use a proper meter. Amazon, Banggood and eBay have them from about three quid upwards.
    Zou and Roger Hicks like this.
  3. PeteRob

    PeteRob Well-Known Member

    Surely it is 240 V? Safest to turn the lighting circuit off at the fuse box/circuit breaker.

    If I (personal choice, not a recommendation to anyone else) did want to go looking for live wires then I'd use a suitable multimeter, properly supported so that I can be very sure that I can see it (or have someone else read it) and watch where I'm sticking the probes.

    As a young lad (7 or 8) I watched my dad make pretty sparks when dismantling a 12 volt old fashion bell push system. Subsequently I found a plug cut from a lamp, nice bit of two-core cable. I plugged it in and touched the ends of the wires together. Sparks! I was seeing flashing bright lights for three days and was lucky not to take my face off when the plug exploded.
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  4. daft_biker

    daft_biker Action Man!

    Think the one I have was twice that price but I got it when I needed it at the local bike and car part shop.

    Never used it in the house though.....everything off and double check by trying an appliance or three. For lights if I'm starting with a working light I want to see it go out when I switch the electricity off and then the switch does nothing. I wouldn't just switch the light off and hope the switch protects me.
    Zou likes this.
  5. dream_police

    dream_police Well-Known Member

    I’d agree with Roger. I have used a pen type of thing. It’s best to test it on a known live first, but I found it a bit hit and miss, sometimes close proximity to a socket set the alarm other times not. I didn’t trust it TBH. I also found that it didn’t last long and it now no longer works. For a few quid I bought a tester with the 2 probes and a digital readout. You know it is turned on as it will be reading 0.0 next to no live.

    Stupid point to make really, but I learnt from experience. Turn off at the fuse board. Don’t trust switches and assume that because the bulb is not illuminated it is turned off. I found out when it went bang and threw me back whilst stripping back wires. Thank god I wasn’t using my teeth as wire strippers, lol.
    Last edited: Feb 13, 2019
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  6. dream_police

    dream_police Well-Known Member

    I’d also add, that even off at the board (upstairs lighting circuit for instance) still check. I once had a rogue live, caused me no end of issues when replacing a rose, had I assumed that it was off and didn’t follow through with my test I could have had a nasty shock. Had to call an electrician to sort it out. He was stumped for a while too.
    Zou likes this.
  7. Zou

    Zou Well-Known Member

    That's basically what I wanted it for - off at board and switch, but just to confirm.
  8. saxacat

    saxacat Well-Known Member

    If I'm just testing to see if a circuit is live, I'll sometimes just use a neon screwdriver. If its a bit more complicated I'll use a multimeter.
    Always isolate the circuit at the fuse box, remove the fuse or trip the breaker; its possible in some circumstances to get a belt off the neutral otherwise.
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  9. Learning

    Learning Ethelred the Ill-Named

    If you need to ask the question then I suggest that you get someone in who knows the answer.
  10. Zou

    Zou Well-Known Member

    Both do the job... Akin to asking someone whether a Nikkor 24-70 is quantifiably better for described purposes than a Sigma 24-70, rather than "wot lense do I need for weddings?"
  11. daft_biker

    daft_biker Action Man!

    Both would do this job however a multi meter is useful for testing batteries.....you can check they have the right voltage after charging and how long they hold it for, or if they are discharged before charging.

    Lots of videos on youtube on using them if you need them, FWIW.
    Zou likes this.
  12. Bazarchie

    Bazarchie Well-Known Member

    Multimeter, I don't trust the pen types. ​
    Zou likes this.
  13. AGW

    AGW Well-Known Member

    I grew up in a house with three domestic circuits...1 DC, 1 AC, and 1 which could be either DC or AC depending on the master switches. I don't like electricity! Turn it off and test it!

    Zou likes this.
  14. Roger_Provins

    Roger_Provins Well-Known Member

    Those pens I've had have all gone wrong in quite a short time. My multi-meters are still working fine after many years.
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  15. peterba

    peterba Well-Known Member

    @Zou, I see that you've got plenty of answers above, but... a word to the wise:- if the Neutral has somehow become disconnected (isolated) from the circuit, a multimeter won't indicate voltage. Therefore, a secondary check (in addition to the multimeter) using a different method would be good for peace of mind.

    I once very nearly fell foul of this kind of situation. :eek: It was a few decades ago, on an old poor-condition radial circuit (admittedly, far more likely to give rise to this problem) but I just thought it worth mentioning.
    Zou likes this.
  16. MJB

    MJB Well-Known Member

    I always get my wife to lick her finger then touch the contacts.
  17. peterba

    peterba Well-Known Member

    Are you sure that you're on the right website, here, Martin...?!! This looks a bit... 'specialist'. ;) :D
    DaveM399 and dream_police like this.
  18. saxacat

    saxacat Well-Known Member

    Its always best to check and check again.

    In 1971 I was a young apprentice electrician and was working with an electrician called Spud, we were adding some extra fluorescent lights to an existing circuit, in a local match factory. The job was nearly done, we just needed to connect our new wiring to the existing wiring; fortunately there had already been a joint in the conduit box, and we had carefully separated the existing cables with them live; however we needed to isolate the circuit, to safely to connect the new fittings. The trouble was we couldn't find the circuit fuse; there were rows of very large fuse boxes with very large porcelain fuse holders, but many circuits were not labelled. Spud decided we'd have to deliberately blow the fuse, to try and identify the circuit. We grabbed another apprentice and got him to stay by the fuse boxes, just in case he could see any indication of a fuse blowing. Spud told me to climb up the scaffold and earth the live cable to the side of the conduit box, as I went to get my pliers, Spud told me not to be a wimp and just use my hand; nevertheless, I got my pliers. Using the pliers I gingerly touched the live cable to the conduit box, expecting a few sparks; well there was a large flash, the cable became welded to the box, glowed red and melted!!! a quick check with my neon driver (multimeters were very expensive in them days), confirmed the circuit was still live.
    We eventually found the fuse for the circuit, it was a large porcelain fuse holder with a 6 inch nail acting as the fuse wire!!!

    It was a good lesson, to always play it safe.

    I sadly never became an electrician, after 4 years life took me in a different direction; but I remember those times with quite a bit of fondness :)
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  19. LesleySM

    LesleySM Well-Known Member

    Reminds me of when I was a kid. I was fascinated by a 2-bar heater and I wondered if the bars were really hot.

    Suffice to say I was thrown clean across the room!
  20. Footloose

    Footloose Well-Known Member

    Obviously using a pen-sized tester is a darn sight easier, but this does raise the question as to why a lot the multimeters don't come with some way of attaching a strap/lanyard to them!

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