Guess the age.. also, how much is going to need ripping out.

[aaronjb]

That's the house electrics as I moved in - as far as I can tell, untouched in probably 20 years (house was built in 1970, I suspect the CU is original, central heating also probably original(!) and the black transformer for the original - inoperative - doorbell)..

Reckon I'm right about that being original?

Now the question really is - I've given up on the idea of doing any DIY (apart from anything else, everything seems to have been legislated out of the question!) so when the electrician comes around to quote for wiring in a feed to the detached garage (SWA under the drive etc etc) .. how much of this is going to have to get replaced in your learned opinions? (I know, I need a proper safety check before you can truly answer that.. but on first glance, if you turned up and saw that..)

Do the regs allow an unprotected run of SWA (as one electrician suggested on arrival), or does the CU need replacing so an RCD (RCBO?) protected run of SWA can be installed? If the CU needs replacing, there's the possibility that more wiring will need to be replaced and .. so on and so forth. So I'm hoping that the regs will allow it to be wired in with the minimum of disruption and without costing thousands (but as I'm learning, any time you think about doing something in a house it ends up costing thousands..)

 

[1john]

Could poss get away with bonding and new CU if you want it up to date.

If there are no obvious signs of add ons and there is no new kitchen then the wiring may well be fine, either way a periodic inspection report would give you a good insight to the condition of the existing installation.

 

[aaronjb]

The only bit of wiring that's been .. I'd love to use the word 'changed' but there are no polite words for what the previous owners did .. modified is in the kitchen (unfused spur running from a socket where they knocked a wall out; and though this may have been before 2008 I can bet they didn't get BC approval for removing the wall - none of which came up with the solicitor when I bought the house, mind)..

Having said that I'm perfectly happy to have the unfused spur removed if it makes the difference between as reasonably priced job and something that's going to make me have a heart attack (from the price, not from voltage passing from hand to hand).


Do I take it from that, then, that the CU is going to require replacing in order to plumb a feed out to the garage?

 

[1john]

Well it doesn't need to be, a seperatre unit could be installed, saying that, you have no RCD protection on socket outlets, IMO it would be safer to have this.

 

[aaronjb]

That's true - no doubting it would be safer to pull it out.. however I was putting that off if possible, because the long game is to get the house rewired completely when the kitchen is done properly

And part of that work would be a new CU, split the ring final circuits front & rear rather than downstairs & up, add new sockets (you can imagine how many sockets a house built in 1970 has in each room!), move the TV point and flood-wire the place with Cat5e..

No doubt when it comes to that I'll get over my aversion to DIY and do some grunt work myself - chasing channels out of the walls and so on, and let the electrician do the bit I'm not allowed to (everything but the grunt work!)


But step one is to get the garage done (apart from anything else, it'll be somewhere to store all the detritus I'm accumulating in the house when I have to clear rooms out to make way for the rewiring!)..



Thanks for the advice though - at least now I know what to expect the electrician(s) to suggest (assuming they're not trying to pull one over like the first fella who came out, who wanted to rewire the whole house before he'd consider it - and no, he didn't go near a test unit to come to that determination!)

 

[Adam_151]

Thats an an original dorman smith loadmaster board (they later brought out a more recent version they called series 15)

Along with no RCD protection, the issue with these boards is that the breakers are all type 4 and while the max zs for say a 30A is not impossible to meet at 0.66ohms for 0.4sec, a little look at the time/current data provided shows that this is actually relying on the thermal part of the breaker rather than magnetic, so will actually take 0.4sec to trip, not be more a less instant as with the mag (which you would need to hit 0.33ohms to hit). Now even if you have a max zs of below 0.66ohms, if you work out the let through energy and then the min cpc size you'll generally find that twin and earth fails every time (and its made worse by the fact that in 1970, it will have been 2.5/1.0*)


*Assuming that the firm that did it did not still have a backstock of 7/0.029

If you are planning on getting the house rewired soon, then as others have said there is no reason why it cannot come from a separate unit for now, and could ask them to leave a bit of slack in the cable near the DB for when its changed.

Actually, I don't think the max zs for 20A loadmasters is too bad, so seeing that you have a few spare ways, you could have a new garage board fitted in the garage with RCD incommer, and come off the existing unit with the 3c swa feed of course leaving a little slack near the house board
the breakers often pop up on ebay from time to time when old equipment is ripped out

 

[aaronjb]

Thanks Adam

The house is all 2.5 for the sockets and 1.0 for the lights by the way - no stranded cores, at least not anywhere I've looked (all the light switches have been replaced and a couple of sockets popped off for a quick check - had to replace the light switches as they were the originals, arced when switched and half of them had been emulsioned over!)

Hopefully the full rewire, when it happens, will be fairly straightforward - all of the wiring comes down a wooden box section in the meter cupboard (pictured) and the floor void is accessible from there.. just means lots of chasing out to get from ceiling to socket level downstairs!

I think probably a new two way(?) CU in the meter cupboard feeding the SWA is the best bet; as ideally I'd like 32A for sockets and 6A for lights with the possibility of another <something>* for a commando socket in case I want to run any single load >13A (like a welder or plasma cutter)

(*<something> yet to be determined .. IIRC blue commando sockets are 16A and only red 415V sockets go up to 32A, but I'm sure whoever comes out to do the job will be able to advise me on that one )

Thanks! Now all I have to do is find someone local who is reliable


BTW, and I know this can be a sore point around here, but do the 'Competent Persons' scheme rules allow for a CP to supervise someone elses work; as in if the electrician is here doing all this can I assist while supervised? I ask not because I want to reduce the cost (he'll still be here the same amount of time, after all) but because, well, I enjoy electrics and I'd like to learn - at least that way if I do any non-notifiable work elsewhere I'll know my work is up to scratch

 

[ban-all-sheds]

If you're planning a main CU replace & partial rewire/new circuits later then it would make sense to keep the garage supply separate.

Which I think is the best design anyway.

I think probably a new two way(?) CU in the meter cupboard feeding the SWA is the best bet;

CU goes in the garage - in the house you have a switchfuse to protect the SWA.

(*<something> yet to be determined .. IIRC blue commando sockets are 16A and only red 415V sockets go up to 32A, but I'm sure whoever comes out to do the job will be able to advise me on that one )

You can get 32A 230V 60309s...

BTW, and I know this can be a sore point around here, but do the 'Competent Persons' scheme rules allow for a CP to supervise someone elses work; as in if the electrician is here doing all this can I assist while supervised? I ask not because I want to reduce the cost (he'll still be here the same amount of time, after all) but because, well, I enjoy electrics and I'd like to learn - at least that way if I do any non-notifiable work elsewhere I'll know my work is up to scratch

Asking him to train you will probably increase the cost....

But with his agreement up front you should be able to reduce the cost by cutting chases and sinking boxes yourself. ( Ask him after he's quoted though.... )

 

[JohnW2]

BTW, and I know this can be a sore point around here, but do the 'Competent Persons' scheme rules allow for a CP to supervise someone elses work; as in if the electrician is here doing all this can I assist while supervised?

Foolishly jumping in on this potentially emotive subject, this is something I have often thought about when reading the 'sore point' threads....

...Is it actually required that, in order to be able self-certify, a Competent Person does everything ('electrical', not the oft-mentioned digging of trenches and chasing of walls!) themselves, or are they allowed to have 'assistants', or even apprentices, working under their supervision?

Kind Regards, John.

 

[ban-all-sheds]

They are, and the classic Qualified Supervisor model invented by NICEIC is just that.

Whether an electrician considers it would be more bother than it's worth to supervise the work of Mr Homeowner is another matter...

 

[JohnW2]

They are, and the classic Qualified Supervisor model invented by NICEIC is just that.
Whether an electrician considers it would be more bother than it's worth to supervise the work of Mr Homeowner is another matter...

Thanks for clarifying; I presumed there has to be some way of gaining real-world experience before being deemed to be competent Are you implying that not all Competant Persons can act as supervisors?

Kind Regards, John.

 

[aaronjb]

Thanks for the advice Sheds (Or Ban.. or whatever I call you )

Being supervised on the job is basically what my Dad did when his house was rewired - of course in this case the electrician in question was actually someone he works with at work on large scale industrial automation jobs (involving everything from 415V 3-phase to 5V TTL signalling & PLCs) so the electrician already knew precisely what my Dad's wiring was likely to be like.. (Before anyone says it; said electrician is a sub contractor and runs his own firm, hence being a qualified Competent Person for domestic & commercial work)

Even then, what my Dad did more of was chasing out walls and fishing cables, while the spark in question did the CU/final fit/testing etc.

Sadly they live miles away, so my chances of finding an electrician happy to do that are slim, since none of them would know what my work is like - I'm happy with that, of course, it's still cheaper (and safer if you assume I'm a numpty - I'm not, but you don't know me from Adam so I could be for all you know ) to have an electrician do the job than get certified as a Competent Person & buy the test kit!

 

[ericmark]

If you have a lot of notifiable work then by using the LABC rather than the member of a scheme route you can have multi-signatures on the installation certificate.

The minimum charge of £100 plus vat means DIY for small jobs is not worth it but with the larger job I think £2000 is point where next band is reached it's not so bad.

If the LABC route is taken then any electrician can help you. Likely you will find one who wants to earn a few extra bob on the side.

The point is there is no scheme operator to call on should the guy you select not be as good as you thought.

 

[ebee]

You mind find someone who is prepared to let you do (and redo?) the chases/boxes etc providing they do all the supervising etc.
You mind find it saves you money or nothing or actually costs you depending on what time it saves/adds the contractor.


Ask yourself, if the CU is being changed, existing wiring checked, additions/alterations being made and the installation is more than twenty years old then might it be more prudent to completely rewire from scratch?

Often the answer is yes.

Are there enough points in the right locations for your use? Probably not.

Pity you are not in my neck of the woods

 

[aaronjb]

Pity you are not in my neck of the woods

Indeed - everyone seems to be miles away

But you're right, when the house is rewired it'll likely end up all getting pulled out - the wiring is 40 years old, after all. That's precisely what my folks had done, too (though their wiring was older, 1960s with a fuse board rather than CU .. and we knew large parts of it were highly suspect by the way the fuses would blow when you switched lights on!).

Once you're that far into a job, chasing lots of walls for sockets and so on.. I imagine the increased cost of just ripping it all out is offset somewhat against the ease of a 'blank canvas'.

'course I might end up having to move out while it's being done!