PAT testing for dummies...

[ColJack]

for a start it can't be PAT testing since the T in PAT stands for testing..

anyway, to the point..

I did some PAT testing today for my brother who usually does it for the group of firms that he works for since he's too busy doing actual production wiring to do it..

so a couple of questions for my piece of mind..

1. do you flash test things like grinders and such? if so what's an acceptible reading? if the tester says fail, does it fail??

2. how old does something have to be before it has to be PAT tested? from brand new or do you take it that out of the box it should be tested at the factory before it leaves..

3. for things like oil filled radiators in an office, what is the re-test frequency?

 

[^neo^]

Know nothing about 1 and 3 , but been on building sites before where they insist on PAT stickers even if you have just opened the box from brand new

 

[kevindgas]

as i understood it

a new item is considered to be safe (rightly or wrongly who's to know!)
and should be inspected/tested annually

any electrical item in an office again should be tested annually (duty of care?)

my understanding is that the manufacturer is liable for failure within first year

but if anyone can be certain that this isn't the case then feel free to tell us your view

 

[ericmark]

for a start it can't be PAT testing since the T in PAT stands for testing..

anyway, to the point..

I did some PAT testing today for my brother who usually does it for the group of firms that he works for since he's too busy doing actual production wiring to do it..

so a couple of questions for my piece of mind..

1. do you flash test things like grinders and such? if so what's an acceptible reading? if the tester says fail, does it fail??

Flash testing is only done after an item have been refurbished before returning it to service and is not part of the normal testing.

2. how old does something have to be before it has to be PAT tested? from brand new or do you take it that out of the box it should be tested at the factory before it leaves..

In theory from new an item could be used until it would normally be retested but in practice it has to be entered on the equipment register and assigned some ID and to show a trend one must know previous reading so they are normally tested before being put into service. Also from experience many new items are faulty from new and to only find out a year down the line means it is hard to return as faulty.

3. for things like oil filled radiators in an office, what is the re-test frequency?

Oil filled radiators in particular have a regular fault in the control box not making good contact with the radiator and often fail on earth continuity so I have always set them to 6 months so they are retested before Winter starts.

But these are odd ones out and in most cases office equipment should inspected every year and tested every 4 years as most comes under IT label but in reality takes just as long to inspect as inspect and test so normally done every year.

There are two exams for PAT testing one for doing it and one for managing the testing. And to my mind where an automatic tester is used the first test should be carried out by someone with both certificates who fully understands what is required. But once the parameters have been set then sending someone i.e. the apprentice out to re-test is OK.

There are items which can't be inspected and tested with a PAT tester for example some freezers which have auto de-frost and some form of dismantle would be required to test. The person who has only completed a 6 week night class i.e. 18 hours training can't be expected to work out what can and what can't be tested. I have seen people go to test a drill with the insulation test until I stopped them before they killed the electronic speed control. I have also seen where items are sold as a pair for example a mag mount drill where the mag mount is class I but the drill is class II test the whole item as class II. An easy mistake if not fully trained.

 

[Spark123]

I don't think you have to flash test unless you have carried out a repair of a double insulated item with exposed metal parts such as a drill, I can't remember ever having used a flash wand in normal PAT testing. (I call it PAT as we also work with Public Address systems)

As for new items, as far as we are concerned all our portables are tagged, registered and PAT tested before being put into service, some things have been known to fail brand new out of the box owing to manufacturing defects or damage in transit etc.

 

[sjwkmje]

I have done PAT testing on and off for a couple of years in a Hospital in a previous job. Different standard and testers (601) but we tested the IEC cables supplied with a standard PAT tester. I noticed we had a lot of L and N reversals on new IEC cables. About 50 + These were brand new. So we had to report it to the MDA (Medical Devices Agency). Just shows even brand new cables can have a fault. This is why we had to accept any kit on site and test it to the correct standards. Turned out to be a production problem and a big recall happened and the company sent out new IEC cables to each hospital that recently purchased the devices with the faulty production batch.

On hospital equipment L and E have to be earthed so we never really lost any equipment because of the failure. Plus our 601 tested was current limited.

Just shows how PAT testing should be done on new equipment.

Adam

 

[tim west]

for a start it can't be PAT testing since the T in PAT stands for testing..

You learn something new every day, i always thought the T stood for Tedious

 

[plugwash]

Is a polarity reversal on an IEC lead really that big a deal? IEC leads are nearlly always used with appliances intended to be sold accross europe (and often beyond) which includes many countries whose plug/socket systems are reversable.

 

[thornton_chris]

Flash testing is considered a 'destructive test'. It should not be performed on a piece of equipment under normal circumstances.
If a manufacturer creates a new product then 1 will be flash tested and if it passes then it is expected that all the others will.
Simply because an item has been refurbished does not mean that it needs to be flash tested. I used to routinely fix/modify pieces of electrical equipment and I was also responsible for PA testing (!). I never carried out a flash test.

The only exception I was ever told about was if a piece of equipment (lets say an iron) is left outside in the rain. You let it dry out and then perform a flash test. If it works after this then great, if you break it by performing the flash test (or it fails) then its time for a new iron.

At the end of the day PA testing is not set in stone. The idea is that anyone responsible for it is given enough information on electrical safety to make their own informed decisions. Training, training, training.

By the way if I'm wrong then don't shoot me down! This is what I learnt by getting a city and guilds in PAT testing and working as a TV Studio engineer.

Any yes polarity reversal on an IEC lead is important.

 

[Spark123]

Is an Iron not normally class I? If so then I don't see the point in flash testing it.
It is just class II appliances with exposed metal parts which have had repairs carried out which need to be flash tested afaik.
I was under the impression it is to prove you haven't compromised the insulation of the appliance whilst carrying out the repair.

 

[thornton_chris]

Your quite right Spark123. Perhaps an Iron wasn't the best example!

 

[ColJack]

quick question..

do 110V extension leads count as class I?

there's no exposed metal to touch and the only way to come into contact with the earth is at the pins of the plug.. or at a push and with a nail or something, the socket..

 

[Spark123]

Yes, 110v leads with an earth core can count as class I however we test them under their own code for extension leads.

 

[ColJack]

AHA... why?

 

[Spark123]

Why class them as class 1? Because you can plug a piece of class 1 apparatus into it which is most onerous class it will be used with.
Why test them as EL3 (Megger PAT 4 code)?
Because it takes into account lead length which will increase resistance with the earth bond test, also checks IR and polarity.