PAT testing of multi way socket strips.

[DenzilPenberthy]

Hi All,

Apologies if this is the wrong sub-forum for this. I work for a large UK university and we've had a few incidences at work now of multi-way trailing sockets with bad earths on one or more of the sockets. Currently they are PAT tested by an external contractor who (I believe) just tests earth continuity at the socket most distant from the flex. This is clearly not picking up the units with just one faulty earth - e.g. the socket contacts have separated from the bus bar.

As we use an external company for PAT testing who charge a fee per test, if we were to test each socket individually the cost would be astronomical.

Is there any industry best-practice guidance for this scenario? I've ordered a copy of the IET code of practice from our library but it will take a long time to arrive.

It has been suggested that we use a 3-light socket tester to verify the earth in each socket. This doesn't test the earth continuity at 25A though like a 'proper' PAT test which is an issue but it is certainly better than nothing. I see Martindale do one which shows the earth impedance which I think would be better still:

Buy Mains Socket Testers Martindale EZ150 Mains Socket Tester 13A 230V ac CAT II 300 V, Model EZ150 RS Calibration Martindale EZ150 online from RS for next day delivery.

What are people's thoughts on this?


Cheers!

 

[ImpededLoop]

The cheapest route would probably be to ensure that your specification requires all sockets on multi gang extension leads to be tested by the PAT company. If you slip this requirement in next time you tender the contract, it will probably cost you very little more.

In the meantime, I think you could take this up with your existing contractor. You are paying them to verify the safety and integrety of these leads and the tests that they are doing are obviously falling short of achieving this.

Out of interest, how many failed units have you discovered so far?

If you work for Estates and you're not already a member, consider joining the Association of University Engineers: Home - aue

 

[ruston]

All individual items should be tested anyway,thats how you find the faulty ones .

Google the Seaward site they have all the information you need on this subject .


Sorry , you are to quick for me lol.

 

[gnuuser]

impeededloop and ruston have given good advice
this needs to be sorted out for safety good luck to you and hope it gets sorted out quickly

 

[DenzilPenberthy]

Thanks All,

After a bit of faffing about I've found this on the Seaward site:

http://www.seaward.co.uk/downloads/015-create-a-test-sequence-for-a-multi-way-lead.pdf

Which basically allows you to modify the test to include an unlimited number of earth continuity tests so you can test each socket separately but all under one overall test. I'll recommend that we do this and leave it to the bean-counters to negotiate this with the external PAT testers.

Cheers!

Also, as requested: last year we had three items which I'm aware of:

One 4-way strip with a cracked spot weld on the earth bus bar. That was in my workshop, noticed it when I was getting 200v p-p on my oscilloscope when touching the probe

also two large (around 12 way I think) strips from rack units that are wired internally with singles and bootlace ferrules had some sockets with dodgy earths.

 

[ruston]

This might be of help to you too. You have to register to download it.
How to PAT Test using Seaward's PAT Testing Guide

 

[Risteard]

From memory the Code of Practice does point out that all socket outlets would need to be separately tested for earth continuity.

 

[Lucien Nunes]

This has been part of my PAT specification since the year dot. I agree it is an important test and many items - especially budget 4-ways and extension reels - show up with the contacts bent, slack, or detached entirely. The cause often seems to be the plastic moulding giving way, allowing the contact itself to get out of position and scrunched up by the next plug to be inserted.

I would avoid the socket-tester scenario as the go/no-go of a neon is inadequate to check the quality of contact, plus very little extra time is needed to do it on the PAT machine. Since I first started using automatic testers I've added programs for 4 and 6-outlet plastic distros (with 4 or 6 tests) and also for metal ones (with 5 or 7 tests to include the case). No-one here would think of not testing all the outlets, and the same for multiway IEC cables / blocks, UPS IEC outlets etc.