Hi, I'd really appreciate some guidance on my plan for adding additional sockets in my garage. It's a new build, built in 2010 the detached garage has a cu with for lights and sockets, installed when new. At the mo it only has 1 double socket, on a 16A mcb, and the plan is to add 3,maybe 4 more sockets. The sockets will mostly be used constantly for small stuff (car battery trickle chargers, etc) but will also run very infrequently a microwave, Hoover, table saw and Lawnmower. My plan is to run a radial circuit from the existing socket with 2.5 T&E (which I think the existing one is wired with), I'm not planning on making it a ring as this seems overkill for what I need - but am I right? Also I might add an outdoor socket as well - for the lawnmower, this will be on the other side of the garage to the other sockets, so can I just run this as a single socket direct into the cu (so 2 radials in total?), rather than joining the others? And am I right in thinking this would be protected by the rcd on the main cu in the house? Finally, where do I stand technically, and realistically in terms of sign off, notification, etc. am i right to say minor outdoor stuff no longer falls under part p? And do I need to worry about things like socket heights (I want one higher up as the microwave will be on a shelf). Sorry for all the questions! Cheers Will
What you're planning to do is all ok Will but it is still subject to part P, its just the notification requirement that has been dropped. Socket heights won't be an issue as it's not a new build that you're doing. If the garage feed comes from a breaker which is rcd protected that will be ok. The work should be tested and certified when completed.
2.5 mm unprotected pvc T&E should not be used in garages due to possible mechanical damage and rodent attack.(rats and squirrals love it) Use it in MT2 trunking/20mm conduit. SWA or FP200 is ok. Don't use 2 ccts from 1 MCB.....altho if you had a ring in there already you are allowed to run a 2.5mm spur' from the same MCB. Nonsense as usual. RS
There's millions of garages out there with wiring just like that, and do you suggest that houses are immune then from mechanical damage?, 'cos there's also millions of them with T&E lashed around like basghetti. It is common to see two circuits originating from one mcb, as long as the cable is protected I can't see a problem tbh, the max draw can only ever be the rating of the mcb. We don't protect T&E in lofts etc, yet I do see more rodent damage up there, primarily because the critters don't have us humans going up there nearly every day to disturb them, unlike a garage. Just saying..........
Please elaborate, specifically indicating where you think the error of my ways are.... I look forward to learning more...altho i do not have the red or green book in front of me in spain for 4 months. RS
I am sure there are lots of garages "just like that "...is it within regs ? Houses are not immume....non integral garages are more prone....as are out buildings. No one parks cars in lofts. It may be common to see 2 ccts , 3 ccts 4 ccts...on one mcb .....but not within regs. Is anyone disputing my comment that you are allowed to have a radial 2.5mm cct spurred of a 32A mcb which also supplies a 2.5mm ring cct as not within regs ? Go ahead make my day... RS
Rulland, if you cannot come back with a technical cohesive argument quoting / relating to / disputing regs or refer to published data ... I suggest that your inane comments are pointless. The very fact that you suggest "as long as the cable is protected I can't see a problem tbh" indicates your lack of knowledge of the regulations. RS
Jeez chill RS, we are actually talking about T&E in a garage...............like 99% of the population fecking use man, Joe Bloggs are going to do what they want to do, It don't matter what the regs say, you spouting on will not prevent that imho, but at least the blokes attempting to do something reasonably safely-unlike clipping a flex along the tree branches etc for crying out loud, you, me, we know what we'd do, but any help, guidance etc, we give has got to be weighed up in the grand scheme of things, and safer to boot.
A "number of radials off a 16A mcb" ? That is not within regs.....'each circuit should have its own protective device'...cant quote the regs as i dont have them at hand. I don't care what 99% of 'people' do. We are supposed to be professionals. Quoting regs is not "spouting on". Just like dropping shower cables in cavities was done all the time...it is...and always has been againt design regs...for very good reasons. I am more than happy to discuss/learn from the very experienced guys on here with diverse backgrounds. BUT, if you want to discuss technical issues...to teach and to learn...Inane comments are pointless. If you can point me to 'further better particulars'...i am more that happy to review them and amend my stated opinion. RS
A "circuit" starts at the mcb or fuse so no matter how many cables are involved it's still only one circuit. There's nothing at all wrong with a cpd feeding more than one cable.
Ok, thanks for all the replies Thanks for the heads up on the conduit, the original "pro" instal has the cables unprotected where running along the joists, but the drop down the brickwork to the socket is in conduit, I want it to look tidy as well as safe, so will do the same. I might even one day board the ceiling, so the unprotected cable would be in the loft as Rulland mentioned. I only want to split the radials for physical layout reasons, I could, I understand run all 5 sockets on the same radial, but this would mean it going left when it leaves the cu to the outside socket, to then return back past the cu to sockets 2-5, thereby (in my amateur mind) just increasing the cable length for no good reason?? Finally how much it's it likely to cost me to get someone to test & certify My handy work (assuming they don't have to fix it!!). Is there any problem if this isn't done immediately? Cheers Will
What you propose is an alteration to an existing circuit. As such there is no requirement to notify under Part P. If it were my garage, I would turn the circuit into a ring, and increase the size of the MCB to 32A. Don't know whether the RCD in the house will offer protection for the outdoor socket, it would depend on whether it provides protection for the garage at present. Easiest way to find out, is to switch off any RCDs in the house and see whether the garage is affected. You could combine this with one of your regular RCD tests. If the garage is not protected by a house RCD, then you will have to change the MCB in the garage for an RCBO.
That is very true, RS. But a circuit can consist of more than one cable. Two or three cables in an mcb/RCBO is a valid safe and compliant method. The 16A circuit would then consist of two or three cables. It is no different to say running a short length of cable from an mcb in to an accessory and from there branching two or three ways to other accessories. Safe, compliant, nothing untoward.
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