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Earth Leakage Clamp Meter - Great Tool!

Foffer
Maybe I'm behind the times and you've all known about these for years!


I've just started using a Megger DCM305E clamp meter which can measure current from 0.001mA to 100A, meaning that its prime application is measuring earth leakage.  Clamping around both meter tails together or around the cores of a specially made extension lead test rig quickly helps track down the offending item causing RCD/RCBO tripping.  This tool speeds up fault finding a great deal and causes minimum disruption in a working environment.


Just wanted to bring this tool to the attention of anyone who like me hadn't heard of it before!


Also, I don't know if there are similar tools made by other manufacturers.....
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    Foffer:

    Maybe I'm behind the times and you've all known about these for years!


    I've just started using a Megger DCM305E clamp meter which can measure current from 0.001mA to 100A, meaning that its prime application is measuring earth leakage.  Clamping around both meter tails together or around the cores of a specially made extension lead test rig quickly helps track down the offending item causing RCD/RCBO tripping.  This tool speeds up fault finding a great deal and causes minimum disruption in a working environment.


    Just wanted to bring this tool to the attention of anyone who like me hadn't heard of it before!


    Also, I don't know if there are similar tools made by other manufacturers.....




    Yes these clamp meters are very useful. I have two types, one with small jaws for smaller cables, and another that has larger jaws for tails etc.


    Z.

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    Inescapable at Elex. Nice to have, but I wasn't sure that I could justify the price. However, if you can make a profit out of one, then you have a good business case.


    I hate to say this, but speeding up fault finding (or at least finding the guilty appliance) does not necessarily lead to greater profit.
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    yup - very good for those 'how close is this RCD to tripping' tests and also if used with care for pairing up  single phase lives and related neutrals in an energised board when the spaghetti monsters have wired it. One live at 15.2A must pair with the neutral carrying the same value. Or if not then  there is a shared neutral somewhere.

    I presume you have now noticed that L-N does not always equal the current in the CPC, as some electrons escape via other paths like the TV antenna or the phone line or the plumbing.. The other trick is to put the wire through the loop twice to increase the sensitivity if need be.
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    I have a more “cost effective” version. I’ll post its make tomorrow. 


    Regards,


    Alan.
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    I reckon I could of done with one of those a few years ago what was happening was that I was having to repair dads TV on a fairly regular basis and I noticed that the metal Ariel plug was giving me a tingle every time I touched it now even stranger after the DNO repaired a cable fault in the street no more tingles all a bit odd don't you think?
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    Are the two matters related Kelly Marie? The T.V.s that I have seen have only a two core flex. 


    Z.
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    Thanks for that info foffer.

    It`s horses courses.

    Quick check Screwfix seem one of the cheapest fot that model, great price variation from different suppliers.

    I have a couple of cheaper clamps one of which is lowish res and helpfull in earth leak situations to a degree and as said a few winds on a coil helps boost the res too.

    I don`t use often enough to justify price of the one you mention.

    If I spend a fiver on something and it does not save me a fiver it is wasted, if I spend a grand on something and it saves me a grand plus a fiver then it`s an investment.
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    I did wonder if they were it seems like an odd coincidence if if the DNO work wasn't related to the tingly TV  although as you rightly say most tellys are 2 wire devices
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    Hi all... bought my one off of Ebay... it's cheap and BRILL!


    regards... Tom
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    Are the two matters related Kelly Marie? The T.V.s that I have seen have only a two core flex. 



    Sounds plausible to me - a lot of old CRT TVs had the chassis connected to supply N (or very occasionally L) some had an isolating transformer on the aerial socket, but I'm not sure they all did. A DNO fault that resulted in N being raised a few tens of volts above earth might well result in tingles, especially if it's TT or TN-S.


      - Andy.

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