Branch off Henley block after meter with swa cable to outbuilding

[DamoZ]

Look up "discrimination/selectivity" with relation to fuses, MCBs etc. Look at the time/current trip curves for MCBs and various fuse types. You should then be able to work out why a fuse is being suggested as the upstream device.

It's nigh on impossible to accidentally damage an SWA in the way you describe - that's the main point of earthing the armour.

Ok that video was helpful, so you use a fuse so that the rcds/mcbs further downstream will trigger first if there's a fault on one of the circuits downstream so as to only shut off the faulty area rather than the whole thing. This would make it much easier to locate the source of any fault because the area that trips out would be more localised. If you used an RCD of the wrong type further upstream then that would cut off the whole circuit, as would an MCB but you could use maybe 100ma RCD but this doesn't seem necessary with because it's a SWA cable and any cable damage will result in everything going to earth and blowing the fuse. I'd say maybe an 80 amp fuse would be good for a 16mm cable that way the RCD or specific circuit MCB downstream CU in the cabin would trip before the fuse blows unless the swa cable got damaged in which case the fuse would blow before the cable melted

 

[Taylortwocities]

i.e a homeowner that did a basic domestic electrians course maybe 25 years ago but then went on to do a computer systems engineering degree at uni and followed that route instead who does his home electrics but still gets it checked and certified by an electrican and everything signed off by building control...

When Building Regulations Part P was first in force I was a member of the IEE (now IET). The Approved Document is produced and published by the IET. The up to date version is here. https://assets.publishing.service.gov.uk/media/5a802da7ed915d74e622ceed/BR_PDF_AD_P_2013.pdf
Back in the day, it was most amusing as many of the dyed-in-the-wool members of the IEE - many had Msc's, Doctorates, Professors of electrics, etc found that they were no longer able to carry out electrical works in their own kitchens!

To return to the Approved Document

https://assets.publishing.service.gov.uk/media/5a802da7ed915d74e622ceed/BR_PDF_AD_P_2013.pdf

please read the section 3, you will find that these are the ONLY ways to achieve notification of the works that you envisage:

The section goes into the steps. I can't be @rsed to give you chapter and verse. There is no option for you to do the work and have some passing electrician to later "sign it off". Both the certification and notification process includes the condition that they are done by the electrician who did the work. If they do otherwise then its FRAUD.

I have to say that LABC really do not want you to take option C. They have more than enough to do without messing around with a tiny project like yours. You would need to raise a building notice (more than a couple of hundred quid) BEFORE WORK STARTS. They will want to inspect the works at many stages to confirm that the work that YOU do complies with BS7671 (got a copy?). And of course, you'll need to carry out all of the first and second fix tests (got a full set of calibrated test gear that covers all of the required tests? - I thought not.) Or LABC will engane the services of one of their sparks. Again, more££££

For Option B. In the unlikely event that you can find a willing 3rd party certifier, you still have to get him/her started with overseeing your work. You need to engage them again BEFORE WORK STARTS. Thats also added £££

The way ahead is option A. As already said. Get your competent and registered electrician on board now.

Thats all the help and time that I'm willing to contribute. Good luck

 

[JohnW2]

When Building Regulations Part P was first in force I was a member of the IEE (now IET). The Approved Document is produced and published by the IET. ...

Without looking back, I can't be certain of the situation back in 2004/whenever, but are you suggesting that it is still the case that Approved Document OP is "produced and published by the IET' ?

The Approved Document P's I've seen (including the current version) say that they have been produced by the government ("The Secretary of State"), bear 'Crown Copyright' and, as far as I can see, contain absolutely no references to the IET other than as a joint author of BS7671.

Am I messing something ?

 

[JohnW2]

The way ahead is option A. As already said. Get your competent and registered electrician on board now.

For those who wish to comply with the law, in terms of bureaucracy and cost-effectiveness, that is probably the appropriate advice.

However, in terms of realities, you seem to be assuming that someone who has paid their subscription to a trade body, ,undergone some pretty dubious 'assessments' and purchased the right books and insurance is necessarily a "competent and registered" person. Is that what you believe?

 

[DamoZ]

Thanks, yes that does sound a bit ridiculous that overqualified people can't do work in their own kitchen but someone who is potentially a bit useless but has done the right course can do. I guess for every x number of people that aren't qualified that do work themselves but are quite capable there will be y number that aren't really capable and also need to have a "caution hot" label on a cup of coffee to stop them burning themselves, i.e. many rules are there to cater for the lowest common denominator in our society to stop them harming themselves and others rather than because they really need to be applied to rest of us. I do actually have most of the test equipment although it's not calibrated and I already have an electrician that's happy to check my work and sign it off (he's a friend, used to be my housemate after uni) and has done so previously when I converted my garage into a habitable room some years ago. I've glanced at theiet website but only for specific things rather than religiously. So what's the situation when the electrician has an apprentice who does the work and then the electrician checks it? I had some work done about 3 years ago and the apprentice did most of it, isn't that fraud too if the electrician didn't actually do it himself? What's the difference between that and getting your own work checked by and with some guidance from an electrician friend? I think probably option B is actually fine for me as I understand it but I might look into option A to cert my own work, although I've no idea what becoming a "competent person" in this sense entails these days. Normally it just seems to mean paying a lot of money for a watered down course with a multiple choice exam at the end. Thanks for the info, it's been educational

 

[JohnW2]

I might look into option A to cert my own work, although I've no idea what becoming a "competent person" in this sense entails these days.

As has been said and implied, what matters in the context we're discussing is that one is a member of one of the "Competent Persons Schemes" run by the trade bodies. As I said, their main interest seems to be that you pay their annual subscription, but they will undertake some (possibly fairly 'trivial') 'assessment' (and/or rely on {again possibly dubious} #qualifications) and may well require you to have copies of current versions of various documents/books and insurance, and maybe (I'm not sure) perhaps even appropriate calibrated test equipment.

Those here who are members of a CPS should be able to explain in more detail, and maybe even give you some idea of the 'cost'.

 

[EFLImpudence]

Thanks, yes that does sound a bit ridiculous that overqualified people can't do work in their own kitchen but someone who is potentially a bit useless but has done the right course can do.

That is not exactly the case and was not even before the alterations in England.

Anyone can do electrical work; it is just that for some work the local authority must be 'notified'.