by ericmark »
Wed Mar 08, 2017 2:03 am
Certificates are a free down load from the IET web site. There is no qualification that makes you an electrician, it's down to your skill, there were 4 categories now dropped to 3 not sure on new 3 so I will list original 4.
Ordinary Person
Instructed Person - This would include an apprentice.
Skilled Person - He can look after his own safety.
Competent Person - He not only looks after his own safety but also safety of others, this has now gone.
What is being said is you may be skilled to fit a plug, but only instructed fitting a socket. An electrician who designs and installs a PLC controlled press will likely require a lot more skill than one wiring a house, and all that the regulations say is you must have enough skill to do the job safely. It does not say you must have a City & Guilds 2391 certificate.
However insurance companies may require some formal qualification, although I have never been required to produce it. I am trained to level 5 i.e. I have a degree in electrical and electronic engineering, however for many years my only qualification was in auto electrics. Latter became a radio ham, and then took some C&G exams. But no one said I had to take exams, fact I had worked as an electrician since 1979 was enough. OK I did know what I was doing, but paper wise I was an auto electrician.
I actually worked as an electrical engineer well before I had any exams showing I knew how to work with 230 volt (low voltage). In other words if you say you know what you are doing, people will believe it. OK to be fair I did know what I was doing, but I did not have any exams to prove it.
In court if you can show how since 1978 one has worked as an electrician then that shows you are competent without any bits of paper. But if I could not show how I was trained by SLD pumps then spent years in the trade, then I would need some paper to show I can do what I say I can do.
So you need something, even a C&G 2382 would show you have some skill, and all that exam really shows is you can read a book. And it is that book you need to follow. The IEE which became IET has for many years produced the wiring regulations, in 1992 it joined with the British Standards and BS7671 was born. This is the bible you have to follow, it's not law, but can be used in a court of law to show a warranty of skill was not used, so it may as well be law.
I don't like twin and earth because it's not protected by a earthed screen, so in theory every circuit using twin and earth needs to be RCD protected. Steel wired armourer and Alitube cable is officially considered as not needing RCD protection, although still need it for sockets, YY cable is not in the official list, but it's more flexible than SWA cable and does have a braid all around the cable, so any item cutting the cable will likely force the earthed braid into the live cores meaning a protective device will open and every thing will fail safe.
Problem with YY cable is water can get in over time and result in the braid failing, but for time your talking about unlikely. Anyway should anything go wrong, you can show you considered the problem and used your skill to reduce it to an acceptable level. In other words your showing the court you had some skill and did not simply connect everything up and pray to the lord, even if really that's what you did. Maybe better is SWA is used?
For me, I have done the work for so long I could guess on the readings and fudge up some results for the paper work, however you can hardly do that, and exceeding the permitted loop impedance is easy to do.
There is so much maths in electrical work, I know from experience what size cable I will likely need, so I guess I will need 6mm cable and once finished I measure and find I guessed right. Not that easy for you.
However by calculation and inquiry is a valid method. So with a incomer of 0.35 ohms and a 2.5 radial of 32 meters you can calculate the impedance at 1.14 ohms and volt drop of 11.5 volt so it should pass, just pass that's on the limits. Oh working on 20 amp design current.
With 6mm instead of 2.5mm the length increases. In fact 85 meters. The impedance drops to 1.08 ohms. Still working on 20 amp. I use a java script program to get figures, and in real terms if the figures you write down seem to fit then even if some one tests and finds it's not correct, you can argue it was OK when you tested.
However where you can see there is around 100 meters of cable used, if the figures on the paperwork have a daft result, then it's clear it was not tested.
Even with my qualifications when I wanted to rewire mothers house with idea of renting it out, I still used a firm to do the job and did not do a DIY, I realise no one would take my word for it being OK if any thing went wrong.
I would talk to insurers first, see what they want, then decide, as you say you need the insurance to be valid, just one person could claim 250k should something go wrong, so insurance is really important.
