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On the BBC news website today (dodgy cable)
Discuss On the BBC news website today (dodgy cable) in the UK Electrical Forum area at ElectriciansForums.net
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They barely took any action what so ever against the culprits and the fact it was not a mandatory recall says it all really..
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Was doing a periodic in a shop last year and a new ring final had been put in for the EPOS, disconnected the cpcs and thought they are thin like 1.0 if not less and the continuity was sky high but the line and neutral was fine. Dodgy cable me thinks and noted in the Report for a rewire in C2.
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They had something vaguely similar in Australia;
Electrical cable in homes could become fire risk in weeks: ACCC - http://www.abc.net.au/news/2016-03-02/electrocutions-fires-possible-as-electrical-cable-deteriorates/7211674
Defective electrical cable - Master Builders - https://www.mbqld.com.au/building-and-planning/industry-information/defective-electrical-cable
That cable has been subject to a recall.
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For me, they should have acted to the full extent they had authority. This is not a situation where a youngster has made a bad decision and we don't really want to jail them. These folks made money out of selling something that could kill people. Ugh.
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I am aware of a dodgy batch of cable that was intercepted by customs from India, they had mixed aluminium and other metals in with the copper to make it cheaper and maximise profit. wouldnt at all be surprised if there is not more of the dodgy stuff out there being installed.
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It might not be the cable that's dangerous.... It's Rodger The Bodger that buys the cheap cable and tries his hand at being a hero.
What is 1.0mm T&E actually good for?
If a product recall was called early on, some of the sold drums would still be unused and returned.... and even a biggish company would have an idea how much was used where in a short period of time. There would be less of these 'timebombs' in houses.
I sense a slight twinge of scare mongering here. If installed and used properly, the circuit that this cable is part of will no doubt trip if the cable overheats.
It might cause a little inrush of jobs for us if the public think they need to rewire their properties, or it might encourage more Rodgers to give it a go.
What is 1.0mm T&E actually good for?
If a product recall was called early on, some of the sold drums would still be unused and returned.... and even a biggish company would have an idea how much was used where in a short period of time. There would be less of these 'timebombs' in houses.
I sense a slight twinge of scare mongering here. If installed and used properly, the circuit that this cable is part of will no doubt trip if the cable overheats.
It might cause a little inrush of jobs for us if the public think they need to rewire their properties, or it might encourage more Rodgers to give it a go.
OP
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1.0mm is perfectly adequate for most lighting circuits, and easier to work with when there are a few cables at one fitting.
And think about the result of a high earth impedance - you may want to re-think that line about tripping.
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If the cable is underrated for its claimed current carrying capacity why would a protective device disconnect the circuit if it overheats.
OP
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but Homebase doesn't sell 16mm T&E???
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I would like to know, but can't immediately see, the actual discrepancy between these cables and what they claimed to be. How far adrift were the actual CSA and resistance per metre? Without numbers, it's easy to overstate the hazard. A cable so far under-size that it is likely to cause a fire in a typical application, especially set fire to a plasterboard wall as one commentator claimed, would be visibly undersized and at least the more knowledgeable and observant purchasers would take it back, triggering an investigation.
Suppose the 2.5mm² had been 2.2, the cable would be considered defective, its sale would contravene all sorts of regulations, any approvals would be null and void, etc etc. But start fires? A ticking bomb? Probably not. Would you expect a typical cable to start a fire when overloaded by a factor of 1.2 (i.e. Ib = 2Iz)? No. Most circuits would still be in spec, those running the cable continuously at its limit might experience a reduction in insulation lifespan, but not a fire. Of course the heat dissipation rises as the square of the current, so this overload causes a temp rise of 1.44 times the expected temp rise. A cable in 30°C ambient running at 70° at Iz has a rise of 40°, so under this overload could reach 30+(1.44x40)=88°C. Won't boil water, let alone start a fire. But to increase the temperature rise by reduction in CSA requires not a 1.2x reduction but a 1.44x reduction in CSA., i.e. cable sold as 2.5mm² would have to be 1.7mm² to run 18° hotter under the conditions I describe, and people would have spotted this.
If the conductor wasn't pure copper it could have had a much higher resistance, and there could be other faults or hazards from poor insulation, although the reports only mention that the copper was undersize. So on the limited evidence I have read, the response was probably proportionate.
E2A of course cables that run hotter put more thermal cycling stress on their terminations, which are more likely to come loose etc. Statistically, then, a slightly undersize cable could be more likely to start a fire, but not because the cable itself gets red hot. Any effect would probably be far down the list of causative factors like installer's competence, tightening torque, quality of accessories etc.
Suppose the 2.5mm² had been 2.2, the cable would be considered defective, its sale would contravene all sorts of regulations, any approvals would be null and void, etc etc. But start fires? A ticking bomb? Probably not. Would you expect a typical cable to start a fire when overloaded by a factor of 1.2 (i.e. Ib = 2Iz)? No. Most circuits would still be in spec, those running the cable continuously at its limit might experience a reduction in insulation lifespan, but not a fire. Of course the heat dissipation rises as the square of the current, so this overload causes a temp rise of 1.44 times the expected temp rise. A cable in 30°C ambient running at 70° at Iz has a rise of 40°, so under this overload could reach 30+(1.44x40)=88°C. Won't boil water, let alone start a fire. But to increase the temperature rise by reduction in CSA requires not a 1.2x reduction but a 1.44x reduction in CSA., i.e. cable sold as 2.5mm² would have to be 1.7mm² to run 18° hotter under the conditions I describe, and people would have spotted this.
If the conductor wasn't pure copper it could have had a much higher resistance, and there could be other faults or hazards from poor insulation, although the reports only mention that the copper was undersize. So on the limited evidence I have read, the response was probably proportionate.
E2A of course cables that run hotter put more thermal cycling stress on their terminations, which are more likely to come loose etc. Statistically, then, a slightly undersize cable could be more likely to start a fire, but not because the cable itself gets red hot. Any effect would probably be far down the list of causative factors like installer's competence, tightening torque, quality of accessories etc.
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"What is 1.0mm T&E actually good for?" Could you expand on that one a bit?
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A rhetorical question.... Homebase sells it by the pallet, so Rodger uses it cos its a couple quid cheaper than the 1.5.
If you want 1.0mm T&E at my local wholsalers, they have to order it in.
If you want 1.0mm T&E at my local wholsalers, they have to order it in.
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who the duck Is your wholesaler!
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Sorry mate you have completely lost me here.
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Surely if a cable was undersized CSA or low quality copper you'd pick this up when you do R1 R2 tests? Even if a cable is undersized it's not a fire hazard if the impedance tests and disconnect times are within spec.
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Agree with that Marvo. We are the last line of defence and we need to be competent and vigilant in our work.
But I also support the idea that cable (in this case) is type approved and may be relied upon. If its not, it should not be offered for sale, not be fitted and not be approvable.
But I also support the idea that cable (in this case) is type approved and may be relied upon. If its not, it should not be offered for sale, not be fitted and not be approvable.
Reply to On the BBC news website today (dodgy cable) in the UK Electrical Forum area at ElectriciansForums.net
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