Class 1 Testing with the Primetest 250

[agbtester]

Hi,

I am new to PAT testing and use the Primetest 250 tester, when you test a class 1 appliance with a long cord which records a fail due to the length of cord, what is the best way to complete the test ?

Is it acceptable to revert to a class 2 test to initiate a insulation test ?

[Grizzly]

... the Primetest 250 tester, when you test a class 1 appliance with a long cord which records a fail due to the length of cord, what is the best way to complete the test?

The PT250 has a fixed earth continuity pass limit of 0.2Ω (unlike, say, the PT350, which is user defined), so if the lead is too long, it'll take your (0.1 + R)Ω over 0.2Ω, and display a fail.
Unfortunately, there's not really a way round this, other than to use a tester that's appropriate for the appliances you're testing.

Is it acceptable to revert to a class 2 test to initiate a insulation test ?

No, not at all.
A Class II IR test is performed in a different way to a Class I IR test (as you should have learnt when you underwent whatever training you had in order to be considered competent to undertake testing).

[Richard Williams]

I am new to PAT testing and use the Primetest 250 tester, when you test a class 1 appliance with a long cord which records a fail due to the length of cord, what is the best way to complete the test ?

One of the features of the PrimeTest 250 is that, although the test will fail if the lead is long and gives a resistance of over 0.2 ohms, it will still let you carry on with the rest of the cord tests. Therefore you will be able to complete the test regardless.

This is not a feature available with many manual testers on the market today. The norm is to fail the Earth Bond and then end the test.

With the PrimeTest 250 it will allow you as the tester to make the judgement call on whether is passes or fails using your knowledge and experience.

The limits are built into the tester for assistance. It is the responsibility of the tester to ensure that the tests are carried out correctly and passes and fails are accurate.

[agbtester]

Thanks to all for their replies.

Richard, could you confirm how you proceed with the class 1 test on the PT250 ?
Is it a case of pressing the class 1 test button again.

I appreciate that it would be my call, and I would need to evaluate the situation before proceeding.

Currently I am gaining knowledge, also studying the IEE Code of Practice, before attending a 3 day course and the 2377 exams.

Regards

[Richard Williams]

Richard, could you confirm how you proceed with the class 1 test on the PT250 ?
Is it a case of pressing the class 1 test button again.

The PT250 will fail the test but should automatically carry on with the sequence without the need for interaction from the user. It will fail the test at the end but you will be able to review the results.

Please see the photo. This is an example test that I have just carried out on an 20M extension lead. As you can see the Rpe test failed but let me carry on through the sequence.



Note that the test is an overall fail due to the 0.57 ohms Rpe reading, however it is a pass for this particular lead.

I hope this helps..

[agbtester]

Understood, but if you are testing an appliance with the earth lead, and say the cord length is long and causes a fail.

How do you complete the insulation and leakage tests, as the PT250 will halt the test ?

[agbtester]

Thanks for the detailed advice.

I have checked the test through on a long extension lead of my own, and it works as you say, no problem.

I have not had chance to run a test on a class 1 appliance yet, but shall do so tomorrow and let you know.

[Richard Williams]

No problem.... Happy to help.

If you need anything else please feel free to contact me.

Hope everything goes well..

[agbtester]

Hi Richard

I have just carried out a test on a class 1 stationary appliance with the following procedure and results:-

Plugged appliance into front of the PT250, and attached earth lead to an earth point on the appliance.
Test proceeded.
PT250 recorded 0.22 ohms on the Rpe earth continuity test and recorded a 'X' (fail), due to a long cord.
It then immediately failed the appliance with an 'X' and fail, without conducting the insulation and leakage tests.

My question is how do I conduct an insulation and leakage test on the appliance, as the earth continuity test is in fact a pass, if the cord length resistance is subtracted from the overall result ?

Thanks

[Richard Williams]

Ahh I see, please accept my apologies, I had misread the post and explained the PT250's action within a cord test.

You are right, when an appliance is being tested the tester will stop for safety if the earth bond reading is over the required limit.

I will speak to our product manager to see what his view is on the solution. Please bear in mind that the PT250 is still a basic tester (albeit with extra features) and the advanced testers allow for full test configuration, including earth limit adjustment.

To clarify, the cord test will allow further test after Rpe fail. The Class I asset test will not.

I have removed my post above to prevent any further confusion being caused with other forum members.

Apologies for the misleading information, I hope it is clearer now.