live to earth continuity?

[charlieboy]

Hi,
After moving a light switch a few inches and reconnecting it I got a slight shock when I next switched it on, though it didn't trip the circuit breaker. I then discovered that whilst I had slipped out to the garage to turn on the supply, my wife had just wiped the (plastic) switch with damp cloth, so I assumed that this had caused the shock. However, to check that there was no leakage to earth, I removed the fuse and did a continuity test between live and earth. The meter didn't give a proper beep, but it did make a slight buzzing sound. Is this anything to worry about?

Thanks
Charlieboy

 

[Spark123]

A basic multimeter with a continuity test will not tell you if there is an insulation problem, an insulation resistance tester is required for this task. If you are wanting to check the continuity of the CPC (earth wire) you need to (in the CU) disconnect the live wire from the lighting circuit fuse and temporarily connect it to the earth rail. At the switch you should now be able to get a low resistance continuity reading with a multimeter between live conductor and CPC.

 

[charlieboy]

Thanks spark123 - Looks like I am using the wrong method to check for earth leakage. For my education though, do you know why I get a slight buzz (though not a beep) in the multimeter when connecting it in continuity mode between live and earth? I did read somewhere (perhaps on another thread?) that doing continuity between neutral and earth will result in this effect. Is the same true of continuity between live and earth?

 

[BSBS]

I would imagine that you were getting the reading becuase one of the light switches was turned on so you your test would have been going up the live conductor through the filiment in the lamp and back down your neutral.. and given that if you have a PME supply Neutral and earth are connected together at the suppliers Cut-out then you would have picked up a faint buzz...

 

[charlieboy]

BSBS, thanks for explaining the buzz on the meter. Since encountering the 'problem' I had left the downstairs lighting fuse out, just in case there was any earth leakage. Put it back in today, and got no more shocks, so all is well. Clearly it was due to over over-zealous wifey with her damp cloth. She knows now not to do this.

 

[Bigbird]

Help!! I too have a problem with a double socket that was recently raised from the skirting by a "so called" builder. It was fine when it was on the skirting but now it is difficult to put a plug in the sockets and the switches can be very stiff to press. Today, sparks came from one of the switches when I tried to turn off the power. Can you tell me what the problem might be?

 

[ban-all-sheds]

1) Not really, not without looking - if you aren't competent to DIY this you should get someone in. Sparks sounds like it should be sorted sooner rather than later..

2) "I too have a problem with a double socket"? - the original problem was with a light switch.

3) Please see Rule 20....