Picture of the (almost) mid-week
- Thread starter Adam_151
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holmslaw
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And what about when we're at work, Holmslaw??
I take it it wasn't some rubbish emergency feed or anything?
Did you get zapped?
Did you get zapped?
No, just a standard fitting, which was live
And no, didn't get zapped... well not really... a slight tingle when taking my hand away from the fitting... however that might have been imagined as I was aware it was live by that time
. I was on a glass fibre set of steps on wooden floor boards, so reasonably well insulated from true earth
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Never assume anything!
My employer teaches me not to trust any metallic surfaces and to check them with a volt stick before touching them. If the volt stick lights, I am to isolate before proceeding.
It may sound anal, but it's stopped me from contact with live parts once already.
My employer teaches me not to trust any metallic surfaces and to check them with a volt stick before touching them. If the volt stick lights, I am to isolate before proceeding.
It may sound anal, but it's stopped me from contact with live parts once already.
A voltstick? lol
Why not use a multimeter, far more reliable. The voltstick will light if there is any potential difference. My voltstick lights when i put it near some pipework in my attic, yet i can touch the pipework no problem. The multimeter shows no voltage. My voltstick also lights up when i put it next to my wifes head. Im sure she is not a robot.
Why not use a multimeter, far more reliable. The voltstick will light if there is any potential difference. My voltstick lights when i put it near some pipework in my attic, yet i can touch the pipework no problem. The multimeter shows no voltage. My voltstick also lights up when i put it next to my wifes head. Im sure she is not a robot.
Multimeters are not approved voltage testers !
Sorry, how do you mean? They measure voltage don't they? Approved or not, they give a more accurate "reading" than a voltstick don't they?
Multimeters can be set wrongly and are more fiddly to hold. If, due to experience, I suspected a casing might be live I would be isolating in the first instance and using the voltage tester to prove dead.
If I felt the need to test all future casings then I would still want to use my approved voltage tester to test for live in the same way as I would test for dead.
The problem arises when you have to find a satisfactory earth to reference test it to.
If I felt the need to test all future casings then I would still want to use my approved voltage tester to test for live in the same way as I would test for dead.
The problem arises when you have to find a satisfactory earth to reference test it to.
OK cool
I test everything before I touch it, but i use a multimeter as its all i have. I use nearest earth (earth or central heating pipes) as a reference and when that shows safe I also use myself as a reference as a second test. Then i work away. Is that OK?
BTW using this method I found 253v at brass switchplates that a electrician had missed, and am damned lucky to not to have had a belt off it. I had tingling, and the sparky thought i was mad because the plate was earthed. The 253v was between a nearby (1-2 foot below) radiator and the plate showing on my multimeter. The sparky was testing between the live and the earth. Guess what, turns out the earth was not earth at all. After he had initially tested I had a rather patronising explanation of how electricity always finds the easiest path to earth, and that I couldn't possibly be getting any tingling because the electricity would always go to earth first. Which should have suggested to him that the earth was not earth. Got him in to fix it (broken earth on lighting circuit - duh), and never called him back again. Hence why I do 99% of stuff myself first, or make damn sure I know what needs to be done before I get a pro in.
This seems to be a cause for concern. If you are not 100% confident that you've found an adequate earth (and establishing that would, in itself, theoretically require some other testing) there is surely the risk of getting a dangerously misleading result with a voltage tester? Do you think there's a case for undertaking a secondary test with a volt stick (or even a neon screwdriver!) in cases in which one is not 100% confident about the earth.
Kind Regards, John.
P
Paul_C
A statement which can be heard repeated regularly, but which is not strictly true. First, electricity will take all available paths to complete the circuit; it's just that the "easiest" path (i.e. the path of lowest impedance) will carry the largest proportion of the current.
Second, to say that "electricity will always try to get back to earth" is rather misleading. It will always try to flow in a complete circuit and get back to the source of supply. If one side of the supply is earthed at source, then the earth just happens to form a convenient path for that current. If you take a system which is electrically isolated from earth (such as the output of a transformer-isolated shaver outlet), then you can connect an earth to either side of that circuit without there being any flow of current* to earth through that connection.
* Ignoring insignificantly small currents due to leakage, capacitance, etc.
Thanks and yes, exactly. Interesting point about electrically isolated circuits, must test that...
So are you saying that you are making yourself part of the circuit, i.e. one probe on a live part and the other probe on your hand?
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