Quick PAT question

[matrixresonator]

So when testing class I appliances you have to have them turned on.
How do you go about testing something with an PCB on/off button that cant be left in the on position? (ie Bosch washer)

[kaibart]

A pat test is basically a safety test you carry out on and electrical appliance 1st you check condition of leak and plug top then you check if the appliance has a good earth continuity if not double insulated, then you carry out a insulation resistance test when doing this the door and dial should be turned to and programme otherwise your not checking the appliance properly,as you say switching on you can go further testing the idiff and equivalent on certain test equipment, so it all depends on the test equipment you use.
Kai

[matrixresonator]

kaibart wrote:so it all depends on the test equipment you use.

I’ve got a Megger PAT120 which goes through the tests automatically in sequence, and stops the test if 1 fails.
Tried it on my washer which passes the continuity, but failed on Insulation It was flashing the symbol to indicated the appliance is turned off and doesn’t move on to the leak test.

I’ve meggered the cable, elements etc and everything comes back good, so I was presuming its failed as there’s no circuit with it being turned off.
As its a digital dial the machine isn’t actually “on” so wondered how you handle this in a test environment.

(I don’t go out testing, but have got one to test appliances after a repair)

[stratfordgirl]

The PAT120 looks like a very basic tester, probably designed for small businesses and charity shops to self-test everyday portable appliances – kettles, desktop computers, electric blankets, etc. I’m guessing they have tried to make it fool-proof by carrying out a quick live-neutral continuity check before the insulation resistance check, to check whether the appliance is turned on. If so, it won’t work on the latest eco-design appliances designed to use close to zero energy on standby.

[matrixresonator]

Was beginning to think that was the case, might have to look for an alternative tester then.

[matrixresonator]

I’ve emailed Megger who have responded this morning.

The tester does a pre-test check before each stage, however pressing the test button again overrides the pre-test and continues the test. Just tried it on my washer and all tests pass successfully.

[stratfordgirl]

Nice, just a reminder to switch the appliance on in effect

[Author]

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