Portable Appliance Testing - (PAT)

Or ... Why should I have my gear tested ?

By Eric Churchyard BSc ( Hons ) C.Eng MIET MBCS

Everyone talks about "PAT Testing". It's an unfortunate turn of phrase, because really , when you think about it - it becomes "Portable Appliance Testing Testing"!

To be honest - the whole idea of what is a "Portable Appliance" can be a bit vague really – it could be almost anything that "you" can connect /disconnect to an electricity supply – and in our case that usually means things like: amplifiers, lights , phone / laptop chargers, mixer desks and so on.

Some items – like a microwave oven, or large Desktop computer ( or even built in appliances like fridges, freezers etc ) could hardly be thought of as "portable" - but still come into the same category when it comes to electrical testing.

So really – rather than use the term "PAT" testing – I'd rather talk about "electrical equipment" testing. In short – testing almost anything we might use that gets plugged into an electrical power supply.

When we connect anything to the electricity supply – we are relying on many factors to ensure that no-one coming into contact with our equipment is liable to be injured / suffer an electric shock. ( and that includes how we position equipment, manage trailing leads etc and checking for obvious things like broken plugs, chaffed mains leads etc - something we should really do each time we setup equipment – and that action is included in the general concept of "electrical testing " as "visual inspection" – which one should really do often )

Using equipment in a "public" place – such as we do when performing live music, even though ( like at home) perhaps the intention is that it's only "us" that is going to use it ( you might say we are "competent persons trained to use such equipment – and so might know how to avoid danger) – we must also take into account the possibility of "others" / general public touching or using our equipment – that is "untrained" people that we might not have direct control over – but nevertheless will hold "you" responsible if something goes wrong.

This is because - sadly – we live in a "blame someone else "/ compensation society now. We see this every day with the way road works / work areas are managed for example. "Those ****** lights for just a little hole in the road, or the "wet floor" signs the cleaner has to put up are examples. All the same principles that apply to having our gear properly tested.

Like it or not - we have to think the same way!
So – we need to be reasonably "sure" that everything is ok.
We need to know we've taken reasonable steps to cover ourselves!
No one can guarantee that nothing will ever go wrong, but you CAN show you've taken fair responsibility to avoid the worst happening. No one can expect you to do any more than that.

So that's the case for having your gear tested.

If you can show its been tested by "others who are competent" – then you can show you've taken fair responsibility - and- importantly, also have another independent "competent person" to back you up if the worst happens. That's what you've paid for – and ... that is why electrical testing might not seem "cheap".

You aren't just paying someone to make a few tests and stick on some labels - you are paying for a whole lot more than that - if it's done properly.
You are paying in essence for someone else "professionally qualified" to say " it was ok" if the worst happens. You can then sleep at night.

The other option is : To do "nothing"

- ( I'm doing nothing because: "I don't need my gear tested- it isn't a legal requirement" , or "my gear is brand new / less than x years old etc" ) Well – I'd say that is NOT an option.
Yes – it's not a legal requirement to have gear tested (surprisingly) – but there are acts of Parliament governing the use of electrical devices "in the work place" etc that are relevant. A look at the Health and Safety Executive website will confirm this

If something goes wrong under the "I'm doing nothing" option – then the buck stops with you. "PLI" may not rescue you either as your insurance will almost certainly want to see evidence of how you mitigated the risk – and if you've done nothing about the safety of your kit - then what?

It's all about being "professional"

Things like Public Liability Insurance, and Test Certification for our equipment are basic requirements we should all have in place before we practice our art "on site".
Just like you'd expect a Doctor, or Vet, or other such professional person that you engage to have all the right things in place, we should think that way too. We are "professionals" just the same are we not? We've spent years honing our art!
And this comes into play when we talk about how much we charge too!

Having these things in place is a good argument for charging more!
Clients need to be shown that they are hiring professionals just like a doctor or a vet to do a job, and that comes at a price!

Electrical Safety

As far as we are concerned – there are two parts to a "safe" electrical system .
The first part is the electricity supply in the building itself, that powers the electrical socket(s) we connect to – and

The second part is: The equipment we plug in.
So - For equipment to be "safe to use" - we have to know that both parts are installed and maintained correctly.

As far as the electrical wiring in the building is concerned – this should have been regularly inspected and tested by a competent electrician to BS7671 , and an "Electrical Installation Condition Report" (EICR) issued . So – what that means is – we can connect our equipment to it– and know that the supply itself is "safe" and properly protected in the case of a fault occurring.

However – from a practical point of view – sadly - we don't often have much control over this.
You can "demand" to see the EICR for the venue you're playing in ... but don't count on it! So - Even more reason to know our kit / side of the bargain is correct!

So now it's up to "us". We are taking it that: the electrical socket(s) is "safe" What about our gear? How do we complete "our side of the bargain"?
So – what is " Electrical Equipment Testing" ? - what tests get done ?

1. Know what kit you've got – Something you can "do yourself" and will save a lot of time when an electrician / competent person comes to test your gear.

So - The first thing you need to do before doing anything else is to compile a list of your equipment - ( called an "asset register" )
This is a list of each piece of equipment, showing date of purchase , price, model number, serial number etc . This is a good thing to do as its useful for insurance purposes ,

Also if you label all your items of kit with its "asset register number" - then you know exactly what kit is yours especially when you come to break down at the end of a gig – and you'll be less likely to lose something when someone else picks up something thinking its theirs – especially things like mains leads, mic leads etc.

So - Its good to list everything on the asset register, including Stands, leads, etc – some of which, such as a mic stand for example, won't need electrical testing, and that can easily be shown on the asset register as " test not required".

There will be other electrical items that may require testing – but - you can leave that part to the competent person to decide what needs testing, and exactly what tests need to be applied

So – When it comes to engaging someone to do the "testing" you are now in a good position – you already have a full list of your kit, and that means the person testing can easily use this to compile a list of "test results" that can be appended to each item on your list. Saves them a lot of time not having to wade through all your kit identifying everything - And - when the "tested" label" is fixed to each item it can also relate to the actual "asset register" - so makes for easy reading / "checking back to the master list" when needed !

When all the testing is complete - you'll end up with your asset register containing more information about each item relating to the electrical testing – such as
Test equipment used, Model no / serial Number AND its calibration Status,
Date of test, date for re-test , visual inspection, "OK" ( or not OK !), insulation resistance, protective earth conductor resistance, electrical "class" of equipment - "class I" "class II" etc , - and finally a statement showing that each item is "ok for use"

Also on the list will be shown items that have Failed !! - and may be listed as needing repair, or in worst case – disposed of .

Now we have a complete list of equipment and it's test results – the tester can now issue a "test certificate" that relates to the test result / asset register

Here's part of our "asset register" showing test results:

You can see clearly what each item is, and its test results - and an "OK" to use column also!

Note also that there is a column for showing what the "fuse" rating is – and this is most important for things like mains leads that have a fuse in the "plug" – because the rating of that fuse is vital in protecting the lead itself - and often plugs sold separately ( as opposed to buying a lead with a plug already fitted) are supplied with a 13A fuse fitted which may well be oversized for the mains lead itself -so you need to know what the correct fuse rating is. Most Often – mains leads are supplied with 5A or 3A fuse .. and knowing what the fuse shouldbeisvital! -asyoucansee -it'sshown intheAssetlist–andso-whenIpickupa lead or an item of equipment - and look at the label on it – it will tell me exactly what fuse should be fitted ! no guess work!

A copy of our test certificate follows:

 

To summarise

A full "formal electrical equipment " (PAT ) test will include all of the following activities:

• Create an "asset" List of equipment
• Identify those items that need electrical testing
• Visually inspect all equipment for damage, broken covers, frayed leads etc.
• Inspect items that cannot be directly seen – such as tightness of terminal screws
• inside a plug – this will mean removal of plug tops , or protective covers etc ( now you can see how laborious testing can be !! – and why it might cost more than you expected!!)
• Carry out electrical test on each item of equipment – and record results on the asset list.
• Exactly what tests needs to be done will be decided by the class of equipment – and to some extent – the Professional judgment of the person carrying out the testing.
• He or She will be referring to guidance From professional bodies such as the Institute of Engineering and Technology ( Formerly the IEE ) - who publish a "code of practice" for "in- service inspection and testing of electrical equipment (current edition : 4th Edition)
• The list below isn't exhaustive – and there are many other conditions to be considered, especially when testing sensitive equipment such as IT equipment
• Tests typically carried out will measure:
• For Class 1 equipment ( that is equipment that not only relies on its "basic insulation construction" – but has exposed metal parts connected to the protective earth conductor – that is via the "earth pin" on the mains plug or equipment mains inlet connector - examples are guitar amplifiers with metal protective covers / chassis / heat sinks etc ) Electrical Tests carried out
• Resistance of Protective earth conductor ( from earth pin on mains plug – or earth pin on equipment mains inlet connector) to external metal / conductive parts
• Insulation resistance from live conductors ( live and neutral pins in the plug or mains inlet connector )
• For "class II" equipment - ( that is equipment constructed so that all internal live parts are "double insulated" that is "basic insulation PLUS supplementary insulation ( think of it as a "electrical box inside a non conductive box " technique - ) so that no external conductive parts can become live ( unless the equipment is damaged – which will show up on the visual inspection )

Test carried out

• Insulation resistance from the live conductors in the mains plug or equipment mains inlet connector - to any external conductive parts. Many Plugtop power supplies / phone chargers and laptop chargers come into this category ( Class II) – so an insulation test is done from the mains inlet to the connections on the low voltage output lead
• Fix "tested" label to each item of equipment. Label will show : Date of test / Date of re-test, Asset list Number and testing authority identification ( signature / name of company) For things like mains leads – its useful to also show the plug top fuse rating too on the label.
• Label any equipment that fails testing as "not to be used" ( and record on the asset register)
• Issue full asset list with all test results
• Issue Test Certificate

How often does my equipment need to be tested?

This is a difficult question to answer. It very much depends upon how and where the equipment is being used. There is a world of difference between the use a power drill gets on a building site every day in all weathers and temperatures, and a desktop computer that sits on a desk in a cosy office , and never gets moved.

For us musicians - we are somewhere between those two.
We move our gear around a lot, it gets put in and out of a vehicle , gets connected up on site, leads get pulled and trodden on, gear gets dropped drinks spilt on it .. and then all gets taken apart and back in the vehicle for the next gig.
Not a totally benign environment. Not as bad as the building site, but a fair way off the cosy office !

We also need to draw a distinction between "formal testing" and regular " or informal visual inspection" / "user checks"
Formal testing is where the equipment is visually inspected, and subject to test by specialist test equipment to establish that the equipment is intrinsically safe and full test results of these activities are recorded and certified. And to establish that there's no significant change in test results from the last test ( Very important !)

For the use our equipment gets .. a reasonable time period for formal test is: once a year.

User Checks - For our use – where equipment is being connected, disconnected often etc these should be done at every gig. In other words, as equipment is being set up – a visual check on things like cracked plugs, chaffed leads, loose cable clamps and the like.
In other words – keep an eye out everytime !

Final Conclusion:

I hope this has clarified the subject of "PAT" or electrical equipment testing.
As you can see -the safety of electrical equipment isn't just about having it "tested" once every now and then, but more about:
How you document what gear you've got, visually checking it often, and then typically once a year, having it all checked by an independent qualified /competent person.

I hope you can also see that testing equipment isn't a simple matter. Its quite laborious if done properly - it can take quite a time just taking plug tops off and checking the right fuse is fitted, and the terminal screws are tight – and also carrying out remedial work.
It all takes time.

It's not about plugging in a "go - no go" checker and sticking a label on.

It's about formally undertaking and recording a full test and check of the equipment, its connecting leads, protective covers, and generally "checking" the overall construction of the equipment is still sound - and "OK" to use.

And – so you can sleep at night!

Eric Churchyard BSc ( Hons ) C.Eng MIET MBCS

 

About Eric

Eric holds an honours Degree (upper second) in Electrical and electronic engineering Higher national certificate in electrical engineering Higher National certificate endorsments in Radio Communication, Computing Technology and electrical measurements City and Guilds final certificate in Radio communication and Telephony. He has completed the "Electricity at Work Regulations Course", a "Level 3 Certificate of Management of Electrical Equipment", "Level 3 Certificate in Inspection and Certification of Electrical Installations", "Level 3 Certificate in the Requirements for Electrical Installations". "He is a "Radio Amateur" (ie he has a radio transmitting licence call sign G3TVR), worked for BT on overseas / transatlantic telephone communication the BBC at their designs deparment working on local FM radio transmitter design, and "colour TV broadcast techniques - colour separation overlay, or "green Screen" as its known today. Worked at "DECCA" designing colour TV circuitry for UK and export use and also woring in military electrical and electronic areas on specialist defence equipment for dealing with detection of submarine type explosives, and the detection of nuclear detonations (cant say much more on that one!!). He has several music qualifications of course (piano grades) and now he runs an internet service provider business - within the data centre he has a fully equipped recording studio and rehearsal facility.