Microwaves and kettles all failed Class 1 test

[shazza]

HI guys, new to PAT testing and here. I recently completed an online course in order to carry out PAT tests annually in 10 rented houses. Unfortunately all the microwaves and kettles in each property failed Class 1 testing. I am using a Martindale HPAT 400 tester and am obviously doing something wrong or overlooking something. Please can anyone help? Thank you x Sharon

 

[westward10]

It what way did they fail.

 

[Moley]

I've got no experience of these basic PA Testers so don't know if it tells you what it's failed on but as they are all class I I assume it's earth bond? You are using the earth probe and connecting it to a bare metal part of the kettle/m'wave? Don't try on any painted parts

 

[Flanders]

As above what test failed how did they fail was is high resistance or no continuity

 

[pc1966]

Once, many moons ago, there were metal kettles that fails the bond test as t'was to the element's sheath that was favoured by the Earth.

And lo! Had they used conductive water the outer would have measured the Lord's conductance and seen it was good!

 

[shazza]

It what way did they fail.

It what way did they fail.

They came up on a class 1 as fail but passed on a class 2

 

[westward10]

Sounds like you are having a problem with the earth bond test (Class II does not require this test). As above you need to ensure the earth bond test lead is in good contact with the earthed metalwork, for a microwave they normally have four screws on the lower edge holding the case in place. For the kettle you need to contact the element if it is a plastic kettle but metal kettles the actual metal parts should be earthed.

 

[James]

Think about it, the only difference between class 1 and 2 tests is the. Earth bond test.
How are you doing the test?

 

[shazza]

Sounds like you are having a problem with the earth bond test (Class II) does not require this test. As above you need to ensure the earth bond test lead is in good contact with the earthed metalwork, for a microwave they normally have four screws on the lower edge holding the case in place. For the kettle you need to contact the element if it is a plastic kettle but metal kettles the actual metal parts should be earthed.

Thank you. I will retest.

 

[shazza]

Think about it, the only difference between class 1 and 2 tests is the. Earth bond test.
How are you doing the test?

On the kettle I test the element.

 

[westward10]

Testing at the element can be a bit hit and miss if it is not shiny and new so you need to break through any build up on it. Ensure it is firmly attached to its base.

 

[shazza]

Testing at the element can be a bit hit and miss if it is not shiny and new so you need to break through any build up on it. Ensure it is firmly attached to its base.

Thank you - going to retry today

 

[James]

You should be holding the probe firmly against the metal with a bit of force, not just touching it lightly.

 

[telectrix]

You should be holding the probe firmly against the metal with a bit of force, not just touching it lightly.

may the force be with you.

 

[shazza]

may the force be with you.

Thank you - will exert extra force today!

 

[DPG]

This is one of those things where it is essential to understand what each part of the test is doing. Luckily in this case it is failing, but I've seen people perform ridiculous tests which will always pass, even though nothing is actually being tested.

Testing figure 8 mains leads anyone?

 

[James]

This is one of those things where it is essential to understand what each part of the test is doing. Luckily in this case it is failing, but I've seen people perform ridiculous tests which will always pass, even though nothing is actually being tested.

Testing figure 8 mains leads anyone?

I give you 50/50 on correct polarity!!

 

[pc1966]

Testing figure 8 mains leads anyone?

True, no CPC or polarity to verify there.

But the opposite gets me, folk passing USB chargers visually on the basis of no earth pin and no cable. To me you ought to be checking the insulation between the L&N and the USB socket is good as I have heard enough horror stories of fake chargers killing folk (usually semi-Darwin by using things in the bath which plugged in to charge, but you get my point).

 

[DPG]

I give you 50/50 on correct polarity!!

I had to explain to a guy working for a pat testing company that the live and neutral were connected together during the test, so no point doing the IR test. And also as you say the polarity issue!

He was happily pressing test and waiting for the pass light each time ?

 

[shazza]

This is one of those things where it is essential to understand what each part of the test is doing. Luckily in this case it is failing, but I've seen people perform ridiculous tests which will always pass, even though nothing is actually being tested.

Testing figure 8 mains leads anyone?

Thank you. It appears that the guy who used to do our tests did everything as a class 2!

 

[DPG]

Thank you. It appears that the guy who used to do our tests did everything as a class 2!

You'd be surprised at the things that PAT testing people do!

 

[Moley]

Testing figure 8 mains leads anyone?

Well, at least it will test if the fuse has blown ?

Just read the specs of this tester. Earth bond is only at 200mA. Hardly worth the effort. You need at least 10A the blow the cobwebs away. I'm not a lover of these very basic units.

 

[shazza]

Well, at least it will test if the fuse has blown ?

Just read the specs of this tester. Earth bond is only at 200mA. Hardly worth the effort. You need at least 10A the blow the cobwebs away. I'm not a lover of these very basic units.

So how can they sell the product as suitable for Class 1 testing?

 

[pc1966]

Well, at least it will test if the fuse has blown ?

Just read the specs of this tester. Earth bond is only at 200mA. Hardly worth the effort. You need at least 10A the blow the cobwebs away. I'm not a lover of these very basic units.

I think 200mA is pretty much all any of the battery units offer.

Do they still make the mains powered testers that could do several/tens of amps bond checks?

EDIT: Yes they do, such as Martindale EasyPAT 1600, Megger PAT320, Seaward Supernova Elite, etc. But cheapest seems to be £400-ish

 

[DPG]

So how can they sell the product as suitable for Class 1 testing?

Do you have the code of practice? This will tell you the specification of the tests for different appliances.

Obviously your course should have covered this as well, but you should also have the latest (5th) edition of the COP.

 

[shazza]

Do you have the code of practice? This will tell you the specification of the tests for different appliances.

Obviously your course should have covered this as well, but you should also have the latest (5th) edition of the COP.

Thank you

 

[telectrix]

for what bit of PAT I do, i use a Seaward 1500X, basic no frills tester. £60 2nd hand in 2008. does the job, 20A earth bond, blows the dust off.

 

[DPG]

for what bit of PAT I do, i use a Seaward 1500X, basic no frills tester. £60 2nd hand in 2008. does the job, 20A earth bond, blows the dust off.

A decent buy. Definitely useful to have the high current bond test.

 

[loz2754]

I had to explain to a guy working for a pat testing company that the live and neutral were connected together during the test, so no point doing the IR test. And also as you say the polarity issue!

He was happily pressing test and waiting for the pass light each time ?

IR testing of class II equipment-

Copisitee edition 5 page 73 - "when testing insulation resistance on a Class II appliance, the test probe should be connected to any metal parts or suspect joints in the enclosure where conductive material may have accumulated. This may require multiple tests."

Also page 72 the limits for insulation resistance test values for Class II equipment are given as 2.0 MOhm.

 

[DPG]

IR testing of class II equipment-

Copisitee edition 5 page 73 - "when testing insulation resistance on a Class II appliance, the test probe should be connected to any metal parts or suspect joints in the enclosure where conductive material may have accumulated. This may require multiple tests."

Also page 72 the limits for insulation resistance test values for Class II equipment are given as 2.0 MOhm.

My post was specifically about figure-8 mains lead testing though.

 

[loz2754]

So how can they sell the product as suitable for Class 1 testing?

From the code of practice edition 5, page 71-

"In practice the low current test will, if carried out correctly, identify a weak earth connection and a battery-powered test instrument that carries out a low current test at either 100 mA or 200 mA will be sufficient for the vast majority of situations. However, the operator should be aware of the practicalities of both methods; a high current test may give a more reliable reading when testing some equipment".

Also, from page 70 -

"The high current test may be appropriate for equipment where a solid connection can be made to the exposed-conductive-parts with the test probe, such as extension leads. This test may identify a weak or corroded earth connection, either by making the connection fail or by heating it up so that the resistance measurement can be observed to increase during the test. However, this test should not be routinely carried out on delicate or sensitive equipment (especially IT or AV equipment), and if done, care should be taken to ensure that parallel earth paths internally are not damaged".

So in most cases the battery-powered tester will be sufficient. But it's down to the operator to make that call. Therefore, perhaps more training is required for an operator to enable them to make that judgement.

I used a Seaward PAT 250 handheld tester for the very small amount of PAT testing I do. But I would, in all honesty prefer a mains powered tester, which gives me both options.

 

[loz2754]

My post was specifically about figure-8 mains lead testing though.

Ah sorry didn't spot that. Oops.

 

[DPG]

From the code of practice edition 5, page 71-

"In practice the low current test will, if carried out correctly, identify a weak earth connection and a battery-powered test instrument that carries out a low current test at either 100 mA or 200 mA will be sufficient for the vast majority of situations. However, the operator should be aware of the practicalities of both methods; a high current test may give a more reliable reading when testing some equipment".

Also, from page 70 -

"The high current test may be appropriate for equipment where a solid connection can be made to the exposed-conductive-parts with the test probe, such as extension leads. This test may identify a weak or corroded earth connection, either by making the connection fail or by heating it up so that the resistance measurement can be observed to increase during the test. However, this test should not be routinely carried out on delicate or sensitive equipment (especially IT or AV equipment), and if done, care should be taken to ensure that parallel earth paths internally are not damaged".

So in most cases the battery-powered tester will be sufficient. But it's down to the operator to make that call. Therefore, perhaps more training is required for an operator to enable them to make that judgement.

I used a Seaward PAT 250 handheld tester for the very small amount of PAT testing I do. But I would, in all honesty prefer a mains powered tester, which gives me both options.

Useful info for the OP. I prefer doing the high current bond test on extension cables, etc..

 

[shazza]

From the code of practice edition 5, page 71-

"In practice the low current test will, if carried out correctly, identify a weak earth connection and a battery-powered test instrument that carries out a low current test at either 100 mA or 200 mA will be sufficient for the vast majority of situations. However, the operator should be aware of the practicalities of both methods; a high current test may give a more reliable reading when testing some equipment".

Also, from page 70 -

"The high current test may be appropriate for equipment where a solid connection can be made to the exposed-conductive-parts with the test probe, such as extension leads. This test may identify a weak or corroded earth connection, either by making the connection fail or by heating it up so that the resistance measurement can be observed to increase during the test. However, this test should not be routinely carried out on delicate or sensitive equipment (especially IT or AV equipment), and if done, care should be taken to ensure that parallel earth paths internally are not damaged".

So in most cases the battery-powered tester will be sufficient. But it's down to the operator to make that call. Therefore, perhaps more training is required for an operator to enable them to make that judgement.

I used a Seaward PAT 250 handheld tester for the very small amount of PAT testing I do. But I would, in all honesty prefer a mains powered tester, which gives me both options.

Thank you - much appreciated

 

[westward10]

Still using this on a regular basis.

 

[loz2754]

Still using this on a regular basis. View attachment 64807

Used to have one where I worked. Great bit of kit.

 

[DPG]

Still using this on a regular basis. View attachment 64807

Nice machine. Unless you're doing loads of testing then you don't need all the modern LCD screens and bluetooth etc.

Plus you don't need the automated tests if you know what you are doing!

 

[westward10]

Handy as a small step also when closed built like a tank.

 

[Moley]

My preference is a Seaward Supernova plus. Great old beast. Bit on the heavy side but don't have to lug it around far. Most of the testing I do (which is only around once every six months) is 110v and the Supernova is one of the few that will power up 110v equipment while plugged into a 230v socket. I like the ability to download the tests and just print out or upload the result to the office. Also use a Megger 420 but nowhere near as good as the Seaward.

 

[Moley]

Handy as a small step also when closed built like a tank.

I do the same with my ductor.

 

[pc1966]

We have a Seaward 100 (I think) somewhere that the technician used to do all of the testing with. fine for the basics and much better than the pass-fail 50 model as we have a few items with high-ish leakage and they are not faulty, just the nature of the beast.

Certainly looked at the Supernova and it is tempting for some time when we have some spare cash...

 

[Moley]

Certainly looked at the Supernova and it is tempting for some time when we have some spare cash...

You can pick them up quite cheap on the 2nd hand market. I think I paid around £60 for mine. Got the company I work for to pay for it's cal cert. If you want the same thing in a smaller case and USB download port look for a Kewtech KT77.

 

[pc1966]

Another quick look suggest they have stopped making the Supernova so none of the Seaward units now do the high current bond test. Hmmm...

 

[Moley]

The Megger 400 series does a 10A & 25A test. It doesn't power up 110v equipment when plugged into 230v socket though. Also the Fluke 6500-2 will do a 10A test. Out of those two I would say the Megger has the easier user interface.

 

[Timbo]

You'd be surprised at the things that PAT testing people do!

I wouldn't. I've seen pat test labels on 24v battery packs on patient lifting hoists.

 

[GBDamo]

This made I chuckle..