Pat Testing Cable

[gareth]

For ordinary run-of-the-mill flash testing of typical theatre lighting and sound equipment, flash testing is unnecessary.

 

For ordinary run-of-the-mill PAT testing?

Argh! Yes, you're right - brain-fade leads to silly typo - replace the first 'flash' with 'PAT' in my post.

[techwsussex]

Anyway, it just goes to show that not all PAT testers are created equally.

[Humour]

 

Surely all PAT testers are created equal...

 

But some PAT testers are more equal than others!!

 

;)

 

[/humour]

[Rowan]

When I went on the ABTT PAT training course, we were advised that Flash testing cables was a good idea it showed the deterioration in the cable. We were also told that with the expected life of a cable, the ammount of flash testing was unlikely to cause a problem.

[Thirdtap]

But some PAT testers are more equal than others!!

 

Yep yep yep

At work I was using our highest spec unit with the auto features. But if you couldn't get a good earth point or had a problem with the test you had to abort and start again. Where as a very low spec machine with a dial and a go button was much better if things weren't happening you could pause work things out and carry on.

Low tech is sometimes much better...

[Andrew C]

Having just done C&G 2377 PAT, I thought I'd just chip in with a quote from the IEE's "Code of Practice for in-service Inspection and Testing of Electrical Equipment". On page 8 of this document it states "This guidance is limited to non-specialist situations such as offices, shops, hotels schools andgeneral industrial locations...."

 

15:10 Extension Leads

Ö.should be tested as a Class I applianceÖ.

 

The length of an extension lead should be checked to ensure that it is not so great that the appliance performance may be affected by voltage drop. Additionally, the length should not exceed the following

 

Core area maximum length

1.25mm2 12m

1.5mm2 15m

2.5mm2 25m

 

2.5mm2 leads are too large for standard 13A plugs although they may be used with BS EN 60309 industrial plugs. Extension leads exceeding the above lengths should be fitted with a 30mA RCD manufactured to BS 7071.

 

 

15:13 Replacement of Appliance flexes

 

The maximum lengths recommended for extension leads are not applicable to appliance flexes or cord-sets.

 

For flexes to be protected by the fuse in BS 1363 plugs there is no limit to their length, provided their CSA are as below.

 

Fuse rating minimum flex CSA

3A 0.5mm2

13A 1.25mm2

[Dave]

Just a few thoughts:

 

Having just done C&G 2377 PAT, I thought I'd just chip in with a quote from the IEE's "Code of Practice for in-service Inspection and Testing of Electrical Equipment".  On page 8 of this document it states "This guidance is limited to non-specialist situations such as offices, shops, hotels schools and general industrial locations...."

Are theatres and related situations "non-specialist"? Methinks not.

15:10 Extension Leads

Ö.should be tested as a Class I applianceÖ.

The length of an extension lead should be checked to ensure that it is not so great that the appliance performance may be affected by voltage drop.  Additionally, the length should not exceed the following

Core area  maximum length

1.25mm2  12m

1.5mm2  15m

2.5mm2  25m

Most touring theatre applications have more than 15m of extension between dimmers and lamp! And what about daisy chaining leads? Does the book given a reason? I suspect it is to do with disconnection time in the event of an earth fault.

 

Also, you can buy ready-made domestic extensions of 25m or 50m made from 1.25mm or 1.5mm cable.

The maximum lengths recommended for  extension leads are not applicable to appliance flexes or cord-sets.

Interesting. So by that reckoning it's OK to replace the factory supplied mains lead on something with a stupidly long one (eg 20m of 1.5mm), but not to have an extension of similar length! There is no difference from an electrical viewpoint.

 

Does the IEE CoP have an author? It would be worth trying to sort this mess out!

 

Dave.

[Andrew C]

Are theatres and related situations "non-specialist"? Methinks not.

I think they may well be 'specialist' in this context. They should be staffed by knowlegable people, with rather more competance than, say, an office worker or brick-layer.

 

Most touring theatre applications have more than 15m of extension between dimmers and lamp! And what about daisy chaining leads? Does the book given a reason?

 

What about it indeed!! Nope, no reasons. It is probably is earth bond resistance issues which is why an RCD is specified.

 

There is no difference from an electrical viewpoint.

 

Agreed, totally insane.

 

Does the IEE CoP have an author? It would be worth trying to sort this mess out!

 

Lots of them. ISBN 0 85296 776 4. Available from the IEE at IEE Publishing

 

And don't get me started on 15:14 "Plug Fuses"

"For the convienience of the user (I read as 'manufacturer') applience manufacturers have standardised on 2 plug fuse ratings (3A & 13A) and adopted appropriate flex sizes."

 

Our tutor was recommending that fuses could be changed to these values.

 

What about the 6A rated IEC feeding a 1kW device?

[Dave]

And don't get me started on 15:14 "Plug Fuses"

"For the convienience of the user (I read as 'manufacturer') applience manufacturers have standardised on 2 plug fuse ratings (3A & 13A) and adopted appropriate flex sizes."

I have encountered the curious idea that 3A and 13A are the "preferred" values for fuses in 13A plugs, and wondered where it came from.

 

I've no idea who made the decision - possibly a trade association.

 

It does seem that manufacturers do whatever they want. My 1600W (6.7 amp @ 240V) Braun hairdryer has what appears to be a 0.75mm2 mains lead (rated at 6.0 amps), with a 13A fuse in the plug (presumably factory fitted, as I don't recall ever changing it). Sounds like a PAT failure to me :D

 

Regards,

 

Dave.

[peter]

It does seem that manufacturers do whatever they want. My 1600W (6.7 amp @ 240V) Braun hairdryer has what appears to be a 0.75mm2 mains lead (rated at 6.0 amps), with a 13A fuse in the plug (presumably factory fitted, as I don't recall ever changing it). Sounds like a PAT failure to me  :D

Can beat that - our 3kW kettle in our student flat, which had a PAT test sticker on it, had an IEC lead with 0.75mm2 cable. Nice to see someone thoroughly tested them, then.

[Bryson]

Ah, but did the lead have a sticker as well? It could have been tested with a different kettle lead...

[Shaun Foster]

When testing an aplience with a removable IEC lead, does the appliance and lead need testing seperately? I am presuming this is so because otherwise a lead with a sticker could be used on anything, which would then apear to be PAT tested, but I think I have seen appliences with only a test sticker on the lead.

[TonyMitchell]

When testing an aplience with a removable IEC lead, does the appliance and lead need testing seperately?

 

yes, it certainly does.

we always test leads as separate entities.

 

if you test lead+appliance as one "item" and label the appliance as "pass", someone could come along and replace the lead with another which may fail a test, and there could be an implied liability as the pass sticker on the appliance could quite reasonably make a user believe the lead is safe.

 

Tony

[TonyMitchell]

Heavy Mains Cables

 

I have made up adaptors for all the common connectors 5/15/16/32/in-line/IEC, etc so have no problems there. Haven't encountered 3-phase yet - would be interested in any views on how to test TPNE extensions and indeed appliances, and how anyone here has overcome this.

 

 

Bulgin

 

Those low amperage multicore mains connectors typically found on "disco" lighting, most of them fail visual coz they are "plug to plug" however Bulgin Ltd did introduce a male panel inlet and trailing socket to their range a few years back, in fact their rep came and proudly issued us samples of the "prototypes" a few years ago. The problem is none of the lighting manufacturers are receptive to change and continue to fit female sockets as inlets, thus promoting bad practice. Full marks to Bulgin Ltd for trying, BUT these things are still a nightmare as far as PAT goes!

 

 

Tony

[Brian]

It does seem that manufacturers do whatever they want. My 1600W (6.7 amp @ 240V) Braun hairdryer has what appears to be a 0.75mm2 mains lead (rated at 6.0 amps), with a 13A fuse in the plug (presumably factory fitted, as I don't recall ever changing it). Sounds like a PAT failure to me  :D

There is absolutely nothing wrong with this; 0.75 mm2 cable will not fail until 55A, the 13A fuse will be long gone by then. What is important is that the cable is fixed to the appliance so that it's use is under control.

[Andrew C]

Haven't encountered 3-phase yet - would be interested in any views on how to test TPNE extensions and indeed appliances, and how anyone here has overcome this.

From the CoP.

 

Test earth continuity as a Class 1 device.

 

Insulation

Notes to Table 2 (acceptable insulation values).

Should be >1Meg

 

5) For three-phase equipment, all the phases and neutral (if applicable) must be linked together while making this test. This may lead towards a sensible working practice for Soca testing, but needs some more thought.

 

You could make a jumper from 13A to 3ph and link the phases together in the socket. Neutral will be linked to live by the tester.

 

It may be easier/safer to use a separate tester for the earth bond as the 3ph - 13A jumper wouldn't be one that I'd like to see in the wrong hands! :D