by ericmark »
Sat Feb 10, 2024 6:32 pm
There are two types of meter the insulation resistance meter, which typically uses 500 volt to test, but uses DC so not a true reading of leakage, however if a RCD is tripping really the only way. And the clamp on meter, so you can clamp around both the live wires, that's line and neutral so shows true leakage.
A normal multi meter is useless to do this job. The clamp on is shown being used on my own supply, showing an 8 mA leakage, the insulation tester blue, is often called a mega who made the early meters, is a stock picture, both cost me £35 each, although the red clamp on was selected as it can also measure DC there is a cheaper variant I think however one must be careful as many will only measure in 10 mA increments, there is also one more expensive to one shown which will also measure frequency.
The clamp on also can detect non contact AC volts so good to show item is dead before removing cover, but one would then confirm with leads after cover removed, so is a good all round meter, one shown is the UT210E the last letter is important, there are about 4 variants all look same at quick glance but some AC only, some AC/DC, and one will measure frequency.
It is about the cheapest clamp meter I could find with 1 mA increments and can measure DC.
The VC608 was also about the cheapest I could find, has a 250, 500, and 1000 volt option, and will also show voltage if in error connected to live cables, however it does not have a low ohm range, only the insulation resistance, most the insulation resistance tester will also test low ohms, again can't use a multi meter as regulations require 250 mA current to measure low ohms, and the standard multi meter including the clamp on shown do not pass enough current to measure low ohms it only goes down to 0.1 ohm, it has a meg ohm range, but the voltage is too low. It also has a volt test to test diodes with, it shows the threshold voltage of the diode.
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- Diffrence line neutral 8 Feb 24 reduced.jpg (15.39 KiB) Viewed 509 times
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- VC60B.jpg (81.06 KiB) Viewed 509 times