Sep 13, 2016
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How do you use clamp meter?
Do you just clamp the line? Or line and neutral?

Also been working with a couple of guys that have earth leakage meters and one clamps the line and neutral and the other clamps the earth?
Can someone tell me the correct ways?
Thanks
 
To measure the leakage from a circuit you need to clamp around all live conductors of that circuit.

To measure the load current you need to clamp around the line conductor.

Clamping around the earth will only tell you the current flowing through the earth, this is not equal to the leakage of a circuit except in unusual circumstances.
 
To measure the leakage from a circuit you need to clamp around all live conductors of that circuit.

To measure the load current you need to clamp around the line conductor.

Clamping around the earth will only tell you the current flowing through the earth, this is not equal to the leakage of a circuit except in unusual circumstances.
Spot on thanks
 
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Lots of people seem to clamp the earth to measure leakage but if any parallel paths exist, as they often do, the result is meaningless. It might be too low if some leakage is taking a different route to earth, or too high (maybe much too high) if the same is true of a fraction of the load current arriving at the origin of a TN-C service.

As per DS, clamping L&N detects the leakage in exactly the sane way as the balance transformer in an RCD, by subtracting one from the other.
 
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Hi, I'm trying to figure why my rcd trips out randomly, trying to trace where there is an earth leak. I have sensitive clamp meter, but the weird thing is I am seeing way more than 30mA leakage (when clamping the meter around the live/neutral feds to the rcd and working thru the circuits, switching on appliances)... For instance the immersion heater shows 2200mA leakage when running but does not trip the rcd. What am I doing wrong?!
 
What make and model is the clamp meter?
 
That meter is not going to measure down to a few mA.
 
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Ok thanks. I thought it has resolution of 0.001A in the manual, I see as little as 0.017A on some circuits. But then these crazy high readings.

Can you recommend a meter for detecting earth leakage on a budget pls?

Thanks
 
Ok thanks. I thought it has resolution of 0.001A in the manual, I see as little as 0.017A on some circuits. But then these crazy high readings.

Can you recommend a meter for detecting earth leakage on a budget pls?

Thanks
I doubt anyone on here will recommend a budget meter for you , as they probably won't have one. There are some lower cost clamp meters available , but they have not faired well
on here by most who have tried them.
 
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If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
What type of forum member are you?
Practising Electrician (Qualified - Domestic or Commercial etc)

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Clamp meter and earth leakage tester
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