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Topic Title: Undersized cables
Topic Summary: Atlas Kablo
Created On: 03 October 2017 01:21 PM
Status: Read Only
Linear : Threading : Single : Branch
 Undersized cables   - rogerbryant - 03 October 2017 01:21 PM  
 Undersized cables   - KFH - 03 October 2017 02:29 PM  
 Undersized cables   - AJJewsbury - 03 October 2017 02:30 PM  
 Undersized cables   - broadgage - 03 October 2017 04:03 PM  
 Undersized cables   - Zoomup - 08 October 2017 09:14 AM  
 Undersized cables   - broadgage - 08 October 2017 09:33 AM  
 Undersized cables   - sparkingchip - 03 October 2017 03:55 PM  
 Undersized cables   - sparkingchip - 03 October 2017 04:04 PM  
 Undersized cables   - davezawadi - 04 October 2017 10:49 AM  
 Undersized cables   - mikejumper - 04 October 2017 02:06 PM  
 Undersized cables   - Zoomup - 08 October 2017 09:18 AM  
 Undersized cables   - davidwalker2 - 04 October 2017 04:26 PM  
 Undersized cables   - Zoomup - 08 October 2017 09:19 AM  
 Undersized cables   - davidwalker2 - 04 October 2017 04:30 PM  
 Undersized cables   - AJJewsbury - 04 October 2017 04:46 PM  
 Undersized cables   - rogerbryant - 05 October 2017 06:55 AM  
 Undersized cables   - broadgage - 05 October 2017 09:40 AM  
 Undersized cables   - broadgage - 05 October 2017 11:06 AM  
 Undersized cables   - Zoomup - 08 October 2017 09:21 AM  
 Undersized cables   - Zoomup - 08 October 2017 09:25 AM  
 Undersized cables   - AJJewsbury - 08 October 2017 09:42 AM  
 Undersized cables   - Zoomup - 08 October 2017 09:58 AM  
 Undersized cables   - Zoomup - 08 October 2017 09:48 AM  
 Undersized cables   - AJJewsbury - 08 October 2017 10:14 AM  
 Undersized cables   - sparkingchip - 08 October 2017 10:45 AM  
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 04 October 2017 04:46 PM
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AJJewsbury

Posts: 16113
Joined: 13 August 2003

It would help if BASEC would specify exactly what was wrong with the cable so that professionals could decide if it was a hazard in any particular installation. "Insufficient copper" is hardly helpful.

Agreed. A lot depends on the "shape" of the missing copper - if it's missing evenly from the whole length of the conductors (i.e. deliberate attempt to save copper by using a smaller c.s.a.) then the risk is probably small and detection reasonably easy (by resistance testing or weighing), but if it's an occasional thinning of the wire in relatively short lengths (e.g. by poor quality machines occasionally over-stretching the wire) - giving say 99m of full size copper then 1m of half-size then a similar missing overall percentage would be much more significant and harder to spot.
- Andy.
 05 October 2017 06:55 AM
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rogerbryant

Posts: 980
Joined: 19 July 2002

Thank you for the replies and thoughts. I wondered if there had been an incident in the UK that had prompted the BBC piece.

Best regards

Roger
 05 October 2017 09:40 AM
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broadgage

Posts: 2452
Joined: 07 August 2007

I am not aware of any serious consequences from installing and then using this undersized cable, but would we know about such incidents ?

There are many house fires every year and some are fatal, but AFAIK samples of electric cable are not taken from the scene and examined for correct CSA, so how would we know ?

And if a reasonably competent DIY er found undersized cable due to it become alarmingly hot, I suspect that many would simply replace it and tell no one for fear of the part pee police.
 05 October 2017 11:06 AM
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broadgage

Posts: 2452
Joined: 07 August 2007

By "insufficient copper" they might mean cable of the correct cross section, but manufactured from impure copper.
Even a small percentage of other metals greatly increases the resistance. For this reason, copper for electrical purposes SHOULD be pure "electrolytic" copper that is very pure.

I suspect some cheap cable might be made from scrap copper that has been melted in a furnace, cast into ingots, and then drawn into wire without ever being electrolyticaly refined.
It would take only small traces of other metals such as brass terminals, soldered joints, or tinned copper wire in the mix for the resulting wire to have a significantly higher resistance than pure copper.
 08 October 2017 09:21 AM
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Zoomup

Posts: 3435
Joined: 20 February 2014

Originally posted by: AJJewsbury

It would help if BASEC would specify exactly what was wrong with the cable so that professionals could decide if it was a hazard in any particular installation. "Insufficient copper" is hardly helpful.


Agreed. A lot depends on the "shape" of the missing copper - if it's missing evenly from the whole length of the conductors (i.e. deliberate attempt to save copper by using a smaller c.s.a.) then the risk is probably small and detection reasonably easy (by resistance testing or weighing), but if it's an occasional thinning of the wire in relatively short lengths (e.g. by poor quality machines occasionally over-stretching the wire) - giving say 99m of full size copper then 1m of half-size then a similar missing overall percentage would be much more significant and harder to spot.

- Andy.


I would use a micrometer to check the copper wire diameter accurately.

Z.
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