Unexpected voltage

Postby sunny » Sun Sep 02, 2007 10:52 am

Hi, I am recently part P qualified, still with a lot to learn. Not a real spark just a fitter who decided to become legal!!

I was testing a celling rose for a fault (turned out to be the switch), across the bulb with the switch on was 240v as you would expect. When the switch was turned off though, there was still around 30v present. This doesn't seem right, any ideas?
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Simply Build It

Postby andy.blackpool » Sun Sep 02, 2007 6:22 pm

no, it doesnt. u need to check the circuit and your equipment
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Postby sparx » Sun Sep 02, 2007 10:06 pm

Hi. If you are using a cheapish digital multimeter then try gripping the two probes & see what you read!!
These meters are always looking for some reading, and will pick up induced voltages from neutrals etc, if you tried with a moving coil analogue meter bet it wouldn't move!
This is why regs. require use of approved mains testers ie multi neon type for live checks, it's a steep learning curve, don't lose heart,regards
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Postby sunny » Mon Sep 03, 2007 9:57 am

Thanks for that SPARX, I'm trying to do all the learning I can. But I was using my expensive part P approved and calibrated voltmeter, possession of which as you know is a requirement of part P. So I guess there really is 30v across it?
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Joined: Thu Jun 14, 2007 12:01 pm

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