Let's Talk about Pat Testing



Pat Testing, special case (electronic switch):

It is easy to misinterpret an insulation test on appliances fitted with an electronic switch.
The electronic switch limits the insulation test scope (only testing power cord).

One solution is to use a substitute leakage test at 40V. This allows testing beyond the electronic switch without powering up the appliance. This approach is particularly useful for computer. It does not energise it and no shut down is required.

Another solution is to power up the appliance and use a leakage tester (leakage clamp meter).

I hope you find the above information useful. Please let me know.

Best regards
Delltek for calibrations & repairs, 07 508 508 200


Hi All

Warning Dangerous Adapter: “Test in Place” adapter (see Ebay Listing**) .

I have seen a number of sellers offering on Ebay in “double ended plug extension lead”.
it is designed to test appliance (earth Continuity test) power on.

Please Do Not buy or Do Not use such test lead.
It is dangerous and you may damage your tester as well as get a shock.

During a Pat test, appliances must be always unplug from the mains.
During a Pat test, appliances can only be energised via the pat tester (leakage or load test).

For more information, please contact Jo on 07 508 508 200 or jdelltek@gmail.com

Best regards



Reliability and accuracy

Not all pat testers are born equal.
However, regular checks are essential to get reliable readings.

A number of tools are available such as checkbox, decade box, voltmeter, bispoke test leads, etc.
Checking your tester leakage, load and RCD functions are a bit more complex but not impossible outside a calibration lab.
On a numeric display pat tester it is easier to detect problem(s) than the “pass/fail” type.
However, a regular monitoring is a must and it needs to be adapted to your particular tester and environment.

For more information, please reply to this email or contact Jo on 07 508 508 200 - jdelltek@gmail.com

Your feedback would be much appreciated and please let me know if you are interested in more talk about pat testing.

Best regards


What I do to check my PAT tester doesn’t involve buying a checkbox, and is relatively easy because I have a tester that shows the measurements it makes as well as the red/green lights for fail/pass. What I’ve done is very like what is described here https://www.pat-testing-training.net/articles/checkbox.php but involves less soldering. Immediately after calibration I check and then use as a reference for a) the earth continuity resistance using the same 25m extension lead, and for b) earth/leakage currents I have two 13A plugs which are internally wired from N-E a 1 or 2 mega-ohm resistor and from L-E a 300 Kilo-ohm resistor. These are extremely simple to create.


Hi Ian

Thank you for sharing your experience and knowledge.
Thank for your solution.

Not everyone has a pat tester showing numeric results.
So the problem and solution may not be as simple as you suggested.
Correctly monitoring your testers one a regular basis remains an essential task.
Other factors also need to be considered: safety, range/level of tests, accuracy and ease of use.

I hope this is helpful, please let me know?

Best regards

For more information, please reply to this email or contact Jo on 07 508 508 200 - jdelltek@gmail.com

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