OT: PAT testing/labelling

[PM]

Originally posted on alt.engineering.electrical.

Two questions on appliance labelling:

1) The IEE code of practice recommends different intervals between visual-only and full testing. Assuming the first test is a full test, the appliance is stickered with a Pass or Fail. Assuming a Pass, then in 12 months a visual-only test is due. If the appliance passes, does the visual-only pass sticker replace the full test sticker, or is it in addition?

2) Is it normal to give appliance IDs to mains leads? AFAICT it is best to give them unique IDs because results of a new test can be compared with older tests. However when we last had them tested they just got 'pass' stickers with no ID. I'd like to know what the norm is, or whether it is just down to site requirements.

Thanks

Pete

[Lino expert]

I'm afraid I can't help you with the first part, where I used to work we did a full test annually, but as for the second (and, again, this is only from experience) leads were given their own IDs as they were open to being swapped from one machine to another. In other words they could be faulty, but the machine fine. Hope that helps even if only a little, I'm sure someone will be able to give a fuller answer.

[Andrew Gabriel]

I haven't come across any companies which implement the formal visual inspections. This maybe because they'd find it too difficult to manage, but is more likely because the companies they bring in to do the PAT testing are unlikely to suggest how their clients should be saving their money. It's also not a large saving as the visual inspection is the longest (and most importand part of) the PAT test, and convincing the customer he's getting value for money by you just staring at his appliance without connecting it to a tester could be a challenge. In most environments where routine PAT testing is done, IME it's mostly done far too frequently in any case, so lack of formal visual inspections isn't a safety issue.

Appliance cord sets are a pain in the backside for PAT testing for many reasons. I don't think there is one universal perfect answer.

[PM]

We'll probably mix visual and full tests on equipment that is awkward to test fully but much easier to visually inspect (e.g. computer servers) and do a full test every time on mains leads.

I've decided to give each a unique ID. We're going for a barcode reader so once each one is labelled it won't be too onerous. The biggest pain will be unplugging the equipment to do the test - but this is required for the visual anyway.

[Andrew Gabriel]

What you can do is modify your testing regime in the light of experience. So if you find that none of your datacentre servers ever seem to have faults, you increase the testing period. You will generally find you can increase it beyond the their lifetime in the datacentre (say, 4-5 years), so you never have to test them. You could perhaps justify this by PAT testing systems as they are decommissioned, and if you can show no faults at end of life, then infer there is no need to test younger systems still in service.

Again, modify in the light of experience. You will probably find (unless you are buying completely crap quality) that leads never have faults when brand new -- all manufacturers are going to be automatically testing them during manufacture. It probably costs something like 4-6 times the cost of a new lead to test one. On this basis it's much cheaper to chuck them out than to test them, sadly. As for how long they last -- that will depend heavily on where they're used. One on a genuinely portable appliance would have a shorter period between testing that one connecting up a fixed or stationary appliance.

The potential weak spot is the IEC connector contacts. However, they can behave differently with different appliances, so unless you say an appliance and lead are tested together and must stay together (which is impractical), the PAT test of the leads is pretty useless, other than visually checking for obvious damage.

[PM]

We're planning to test new stuff as it comes in. This will have additional benefits which are not immediately obvious, e.g. SOX compliance reasons.

The problem with throwing away leads and getting new ones is there's no record of how old a lead is or when it was changed, unless the leads are tested when they are bought - in which case, might as well test the old ones .

I can think of some scenarios - cables being crushed for example - where a visual test may not be enough. I agree that the visual inspection is by far the most important check, however if recording the visual check is done by using the PAT tester anyway - which we're planning to do, to be able to demonstrate the check has taken place - the additional 'full' test won't take much longer.