Surely you would double the current flow, hence why you need more current to produce the same amount of watts with less voltage.
I think construction sites are double phase of 55v making 110. Although lower voltage means more current to *power* the device; conversely, you need the force (being the voltage) to be able to push the current through. As an example, a small car will have a 400A battery on it (a big diesel car may have a 900A). You can put one hand on each pole to complete the circuit and won't feel a thing because its only 12v and not enough to push the full capacity the battery can deliver on a cold morning (thats where you see them rated as CCA - cold cranking amps) through you. Not sure if thats the best explanation in the world, but my version of it!
This installation was designed and perhaps constructed to the 16th edition. As such there was no requirement for RCD protection.
cut from the IEE site ........ The Mr Hoult the NICEIC QS was found guilty last week of the charges relating to Section 7 of the Health and Safety at Work Act. Mr Tomkins the electricians mate was found not guilty today of charges under section 7 of the Health and Safety at Work Act by a majority verdict of the jury.
lots more detail on the IEE site - seems to be a reasonable verdict but does highlight a scenario likely to be found in many properties, even those that have been tested in accordance
Making up test certificate results is inexcusable although i would be interested in others views on what test may have helped here. If the screw nicked the line conductor only; i am not sure if it would have made much of an impact on the R1+R2 reading because the screw would have replaced the missing copper. Thoughts?
the threads could have come to rest just touching the conductor, with no damage - but a good enough contact to pass a lethal amount of current - in a dry building I can't see how any of the standard tests would find such a ''fault'' no excuse for the mentioned case, not that anything will change as a result
The fatal circuit was only completed when the poor lass touched the water stopcock. Up to that point she was mopping up water. I wonder if this is a case where no bonding would have saved her? if the water pipes had not been bonded (assuming that the incomer was a blue MDPE) maybe she would not have received a fatal shock as there was no circuit to complete. I am still mulling over bonding and after all this time in the trade I am still not convinced it should be carried out.
I guess the question is: is the risk of potential greater from outside the house than inside when it comes to bonding water and gas. That said, if the water wasn't bonded but the central heating pipes were; it would have completed through that.
there's a more reasonable argument that says that all conductive materials used within the construction should be bonded within a domestic environment as I understand is required by the EAWR
That may well work if all of it was bonded. However, if any part of it is omitted, accidentally or otherwise, the entire bonding system is breached and this is what happens. No bonding at all is better than some bonding IMHO. I don't believe the rest of the world do bonding, its a British thing.
Reading John Peckhams longer of the two reports, it appears that had the proper testing regime been carried out prior to the circuits being energised the insulation resitance test should have revealed the fault and the accident been prevented. Quoting from the article "The installation had been energised without any testing and the fault current had blown away part of the screw and CPC. This was verified by forensic examination at the HSE laboratories. This left a high resistance fault from the line conductor to the metal studwork." However, finding the circuit energised then powering down and following a proper testing regime the test to verify earth continuity would have shown an anomily with the connection to the flex outlet even if the insulation resistance test passed. I am inclined to agree that no bonding may be better in certain cuircumstances. The other opetion of course is to install plumbing in plastic throughout and reserve copper/metal pipework for gas. Kind regards BS
I've seen that IEE thread, was Peckham acting as an EW for this case or are his posts a précis of something officially released ?
I don't know Sean. But if his post is accurate then my comments stand. If he is passing an opinion then I would happily reconsider based on fact. Kind regards BS
I wasn't questioning your comments, it just appears that Peckham is making his remarks as if he has some authoritative knowledge of the case - it would be interesting to read the full reports, direct from the horses mouths (so to speak)
No Sean, a discussion. I completely agree and assumed that Peckham had some position in the case. I have checked the HSE database and nothing has appeared yet to give any indication, althoug the information there would be sparse. The fgull reports would be very interesting. Kind regards BS