PAT Testing

[dom19]

Hi Guys,

I'm looking for some advice - I have just done my PAT testing course and have been asked by a venue that I volunteer at to PAT test their lanterns. I just am a bit nervous as it will be the first stuff I have put my initials on so want to make sure it is right so wanted to double check which tests I should run on the lanterns. Do I just treat them as a Class 1 product so earth bond test, insulation test, and leakage test? I have read in other places that you need to take the lamps out first as well?

Also would sound/light desk have the same tests as above?


Thanks a lot in advanced!! Sorry I am just a bit nervous!

 

[BillConnerFASTC]

This seems uniquely UK. It will be interesting.

 

[Amiers]

Gotta ask cause google isn’t really specific. What’s a PAT test?

 

[RonHebbard]

Gotta ask cause google isn’t really specific. What’s a PAT test?

@Amiers I suspect the acronym is Portable Appliance Test, thus PAT Test is redundant (Of course redundant testing would be even better)
Toodleoo!
Ron Hebbard.

 

[BillConnerFASTC]

I have to assume this is partly a result of the "ring" system of wiring, which as I understand it, connects a large number of devices - receptacles for instance - of the same circuit of significantly greater ampacity than we in the US are use to. So, you might have 50 amps at the receptacle, and thus each "appliance" has OCP in the plug or appliance. I have a few old adapters that are fused. I'm not sure 15 or 20 amps kills any less quickly than 50, but they do have much smaller circuit breaker panels - and less wire overall - and gray vs green grounds IIRC. The ring means fed from both ends so it somewhat balances loads a little better than half on each of two circuits, with all on one but fed from both ends. Takes a little pondering to see the efficiency - all except for those fuses in every plug in this age of fast increasing numbers of appliances. I have tow plug strips and two USB hubs just to power things in my one person office.

 

[YesItWillWork]

Yes, the vast majority of things you will find in a theatre are Class 1 appliances and don't require any different or special treatment to what you will have learnt on your course. Remember that of the visual test is really the most important and will almost certainly be what most things fail on. I spent two days last week PAT testing 130 second hand fixtures and multiple crates of cable our venue had purchased. I failed maybe 30 items on visual inspection, and only 3 items from the actual testing.

I can see no reason at all that you would want to remove the lamp before testing the fixture. The closest thing I can think of is testing Selecon Pacifics where you have remove the lamp base assembly to access the earth point for testing. This is because the rest of the fixture body and barrel are suitably insulated from the lamp/wiring assembly such that they are not earthed.

 

[Crisp image]

I have to assume this is partly a result of the "ring" system of wiring, which as I understand it, connects a large number of devices - receptacles for instance - of the same circuit of significantly greater ampacity than we in the US are use to. So, you might have 50 amps at the receptacle, and thus each "appliance" has OCP in the plug or appliance. I have a few old adapters that are fused. I'm not sure 15 or 20 amps kills any less quickly than 50, but they do have much smaller circuit breaker panels - and less wire overall - and gray vs green grounds IIRC. The ring means fed from both ends so it somewhat balances loads a little better than half on each of two circuits, with all on one but fed from both ends. Takes a little pondering to see the efficiency - all except for those fuses in every plug in this age of fast increasing numbers of appliances. I have tow plug strips and two USB hubs just to power things in my one person office.

This has really nothing to do with it.
PAT is ensuring that a device/product is electrically safe to connect to a supply. This first test is a visual of all cabling plugs and general condition of the device (meaning that no exposed cable or insulation)
The second part is the Class I or Class II test. Class I is used for items that have a ground connection. Class II test is used for double insulated products that have no requirement for a ground connection.
There are testers available that will place excessive voltage (eg 500v ish) to check the insulation leakage. Anything with a switch must be turned on (power drill) for the test to be completed.
Things that are not electrically tested are the little plug packs like phone charges that plug directly into an outlet without the need for a cable on the ACV . These are a visual inspection only.
There is a bit more to it but that is a start.
Interestingly I understand (read as could be wrong) that the first appliance tester built was in Australia by the former State Electricity Commission of Victoria (which I worked for before it was privatized but that is another story) "Test and tag" is another term for the process.
Testers are not able to repair unless qualified to do so and may not destroy a defective item. The item simply must be tagged as failed and the owner notified.
If an item has a tag on it it means it passed the test on the day it was conducted and you should still visually inspect it before use for defects.

In the case of how many amps it will take to kill can be measured in milliamps.

I hope this helps understanding what PAT is.
Wikipedia has more info for you to read at your pleasure.
Regards
Geoff

 

[Amiers]

I guess ya learn something new everyday.

I didn’t think you needed a course on how to check things as simple as a fixture to give it your blessing to use and not as complicated of one as what you make it seem like @Crisp image . I could see this with some high voltage stuff but outside of that it sounds like overkill.

 

[dom19]

Yes, the vast majority of things you will find in a theatre are Class 1 appliances and don't require any different or special treatment to what you will have learnt on your course. Remember that of the visual test is really the most important and will almost certainly be what most things fail on. I spent two days last week PAT testing 130 second hand fixtures and multiple crates of cable our venue had purchased. I failed maybe 30 items on visual inspection, and only 3 items from the actual testing.

I can see no reason at all that you would want to remove the lamp before testing the fixture. The closest thing I can think of is testing Selecon Pacifics where you have remove the lamp base assembly to access the earth point for testing. This is because the rest of the fixture body and barrel are suitably insulated from the lamp/wiring assembly such that they are not earthed.

Thanks a lot for that -really helpful - as @Crisp image suggests would 500v be too much for a leakage test for this equipment so should I use the 250v test instead?

Many thanks again.


Dom

 

[Crisp image]

Thanks a lot for that -really helpful - as @Crisp image suggests would 500v be too much for a leakage test for this equipment so should I use the 250v test instead?

Many thanks again.


Dom

A leakage test will use a higher voltage to test the insulation. It is a bit like working load limit in the fact there is a safety factor involved. Your test machine is smart and will apply the correct voltage for the given application.

I guess ya learn something new everyday.

I didn’t think you needed a course on how to check things as simple as a fixture to give it your blessing to use and not as complicated of one as what you make it seem like @Crisp image . I could see this with some high voltage stuff but outside of that it sounds like overkill.

It seems the country that thinks they are leaders are again playing catch-up with Australia. Australia was the first country to have mandatory seatbelts in cars, had the first surf lifesaving club that provides lifeguards at beaches, provided the world with petrol motor mowers to manicure the lawns and many more things we now take for granted

It is all based on electrical safety. I have mostly seen in contractors on building sites that must have all tools tested every 3months.
While it is important to inspect your gear before use the test procedure will tell you if internally the cables are good including the correct polarity. I am sure we have all come across cables that are wired incorrectly or are faulty. Depending on the device and how it is used dictates the test cycle. Hire gear would be 3 months or before it leaves the shop, fridges and microwaves might be 5 years because they are not moved around. Things that are moved often or are subject to harsh conditions are subject to more frequent testing.

I beleave it has its place in our modern society.
Regards
Geoff

 

[Lyle Williams]

Not everything is manufactured properly.

Given enough time, everything will fail.

Electrical testing and inspection is about discovering things that are faulty and withdrawing them from service.

 

[Les]

I would be interested in seeing some data showing that PAT testing has a positive effect on fire safety and employee safety in general. I'm not doubting that there are benefits, I'm just interested to see if these benefits actually manifest themselves as a lower occurrence of fires, shocks, electrocutions, etc. Does such a table exist? Otherwise, it can be difficult to justify the implementation of such a system. Many electrical fires and shocks I hear about are a result of misusing an appliance, extension cords, etc rather than faulty appliances themselves (not that it doesn't happen).

Another curiosity - are houses and buildings routinely inspected? Commercial buildings in the US are (or should be) inspected regularly. Houses are usually only inspected when being purchased.

 

[Lyle Williams]

In Australia several initiatives were implemented at around the same time. Mandated GFCI/RCD, portable appliance testing, and a "look up and live" advertising campaign about overhead power lines.

Collectively, they have halved the number of electrical deaths. I accept that most of these avoided deaths were in the construction industry.

The key from my perspective is not to be driven by a goal of policy compliance, rather to be driven by a goal of improved safety. Have a tester on the bench where you test gear for functionality before use. While you are doing that, test for safety too. It only takes 30s longer.

 

[Les]

Here in the US it is an uphill battle just to get construction workers to use an extension cord that isn't held together with electrical tape (at best). Many, especially in the residential markets, speak zero English and don't often have the skills to identify these hazards - or they don't get paid enough to care. Supplying each site with someone who is capable of testing equipment, especially that which is owned by the worker himself... Well, I don't know how that would go over. Obviously, we have our share of groundwork to do before anything even remotely like you describe could appear on most construction sites. Commercial/industrial sites may be better, but most of my experience has been in residential. Those guys are historically low on the totem pole and a complete change in culture (and hiring practices) would need to take place.

Luckily, the temporary utility poles supplying these sites are outfitted with GFCIs & OCPD's, at least as of 2007 when I worked in that industry.

 

[BillConnerFASTC]

Of all the causes of accidental injuries and deaths, I gotta say this one doesn't concern me too much.

 

[Les]

Of all the causes of accidental injuries and deaths, I gotta say this one doesn't concern me too much.

In the construction industry, electrocutions account for about 8% of accidental deaths in the US. Falls are the top killer at nearly 39%, followed by Struck-By, at ~9.5%.

I'd wager a guess that many of those electrocutions are due to accidental contact with overhead or underground utilities, failing to comply with LOTO procedures, or improper tools/PPE when working on energized equipment.

 

[Lyle Williams]

Getting people to use a GFCI/RCD in construction here was easy. $3000 on-the-spot fine for not using one.

.

Back to PAT. If your equipment is used for long enough, some of it will begin to fail. Some of those failures will have safety implications. There needs to be a way to detect problem gear and withdraw it from service.

There is also a need to be safe across many disciplines. Putting too much focus on electrical safety while ignoring potential slips-and-falls would be foolish.

 

[Crisp image]

There are people who do testing and tagging for their job full time. They will come to your business or workplace and inspect, test and tag your equipment for you att a cost of about $4 per item (cheaper for bulk items) so you can get on with your job.
Like Lyle says the heath and safety authorities here are on to such things like this and the non compliance fine is not worth not doing it. They would normally issue an improvement notice before fines but if you were a repeat offender then the fines just go up.
At the end of the day electricity will not discriminate and will bite anyone it wants to. If we can be proactive in checking our gear then it may save a life.
One of the things on this site is we will not give advice on how to wire this and that because of the safety factor of getting it wrong.
Tested gear is really only safe at the end of the test and tomorrow that may change but it is a start.

 

[Lyle Williams]

Getting someone in to PAT test is often a horrible solution, due to the interruption of your workflow.

It's much better to just be able to test new gear as it is unboxed, and test old gear as it passes in front of you.

.

I don't think anyone looks at my test tags, other than me.

The fine I mentioned above is in construction where there is much greater vigilance due to the risks on those sites.

I don't keep count, but I estimate that I have 350 powered items or power cables. As I recall I have found ~15 items (mostly cables with transposed Active/Neutral) that needed to be pulled from service. IEC leads are the worst offenders, as I sometimes get other people's leads back instead of my own.

 

[BillConnerFASTC]

In the construction industry, electrocutions account for about 8% of accidental deaths in the US. Falls are the top killer at nearly 39%, followed by Struck-By, at ~9.5%.

I'd wager a guess that many of those electrocutions are due to accidental contact with overhead or underground utilities, failing to comply with LOTO procedures, or improper tools/PPE when working on energized equipment.

I think electrical is much lower in the general population.