The new garage is nearly finished - Ill get the build thread up tonight - so I am now starting to think about the electrics. I have worked out I want 4 double sockets on each side of the main car bit, and then a further 1 double on each side wall and 2 on the back wall of the "shed" area of the garage, this way I will never be too far from a socket. for the lights I am think a double strip lamp on each roof truss, wired up with the 3 back trusses being on 1 switch and the front 2 on another as 9 times out of ten I will be working in the middle to back area of the garage so no point having lights on above the boot lid or blocked by the door if it is up if I am not working down there. My main question is what type and size of consumer unit would I need? as looking on screw fix there seems to be number of different brands and sizes to pick from... I am guessing something like this would be fine - http://www.screwfix.com/p/mk-sentry-4-way-rcd-garage-consumer-unit/33248 (b&q will sell you the same unit for 65!!) with one switch to cover the sockets and one to cover the lights. I might have a welder at a later date, and I will have a compressor at some point too but I should be ok, I hope. I have been told to use 2.5mm wiring from the house, and the consumer unit in the house has a 20A breaker fitted for the garage wiring (the old wiring from the unit to the out side wall is being used for ease as I don't fancy trying to chase the wiring through the house etc) The fitting of the sockets and lamps I will do my self but the wiring will be done with my sparky mate, but I don't want to be hassling him too much so wanted to see if I could get the consumer unit and wiring etc before he comes to help check the wiring and connect it up to make his life easier any help or advice is appreciated Karl.
As a min run two 2.5's, ideally a 6mm or a 10mm. I have run my lathes on the round 15A blue industrial plugs, so one of those on a seperate fuse would be sensible for welders or anything that takes 10A or more. Buy a consumer unit twice the size you need, you wont regret it
2.5 is really limiting you. 2.5 is good for 20A. Your house is fed from the Supply with 16sq which allows 64Amps. Ive 6sq run to mine which runs my 240 mig from a 16A(ire) blue socket and a few lights at the same time. We have other sheds for the other things so 6sq was going to be plenty for me. 10sq minimum if I were you. If its your main garage you just never know what you might need to feed so dont limit youself now. Great advice from Jon- twice the size for sure. A double row board, for roughly 20breakers imo.
Definitely go bigger, as said, that way you can add in dedicated breakers for the welder and compressor later. This is what my mate has in his; There`s more in there now, but it runs about 15x 6ft twin strips, several twin sockets, water heater, huge twin-motor compressor, extractor fans, and the MIG. Don`t ask me about ratings though...he`s the spark, not me!
The problem at the mom is that garage is being connected to the wires already running from the house and poking out of the back wall. I will have a word with my sparky mate as we could possibly look at doing a new feed from the main fuse box, but this would mean running a new wire around the out side of the house (the wire there at the mo is run through the roof spare and walls etc and I am not going to disturb that due to the kitchen just being re fitted and plastered.. plus I have connected a out side socket at the mo to that feed so the builders had easy access to power out side so I might just leave this on its own breaker as I have room for 1 more on the consumer unit in the house)
Doesn't necessarily need to run from the board, is the meter box outside? If so, you can split the tails, put in a small switchfuse and run an armoured cable from there to the garage. As said, put in 10mm minimum
the house is a mid 50s, so the meter is in side, as is the box. one guy at work recons that 2.5mm will be way too small for the length (from the back of the house its about 17M into the garage fuse board). I have got a spare room for 1 more prtected by RCD and it is feasable to run another wire down the wall of the pantry, through the air brick and then round the out side of the house (in a cover to make it neat and extra protection) but this would give me a run of prob 25 - 30m or so.
You need to know a; how much you want to run as a maximum in kW or A, b; the total length of the run. c; how the cable is run (in insulation, clipped direct, buried) d; what the cable is (t+e, armoured) I.E. If you want 20a, its in twin and earth, and the total run from the board is 20m - it should be minimum 4mm cable, due to volt drop affecting fluorescent lighting.
a; how much you want to run as a maximum in kW or A, - not a clue really.... Im planning on either 5 double florescent lamps or a number of normal barnet fittings as I have a shed load of energy saving bulbs left over so could easily run say 3 13W instead of each tube, they will be wired up to 3 switches so I can chose to have either all on, just the "shed" bit of the garage, the middle or the front of the garage. I pan on having a compressor at some point, and I normally use tools like angle grinders etc. I may also have a middle of the range mig welder at some point, but nothing over the top. b; the total length of the run. max run if I go straight from the fuse box, around the edge of the house will be 20M tops c; how the cable is run (in insulation, clipped direct, buried) Around the house it will be run inside a conduit to protect it, then when it goes under the path and into the garage for the last 8m or so it is run inside a plastic 2" waste pipe to protect it d; what the cable is (t+e, armoured) it will be armoured just to be on the safe side, unless there is something better? or cheaper that works as well and is still the correct way to do it? cheers for your help, Karl
Its the compressor, welder and likelihood of a heater that will cause issues if you only run a 20a supply. I would just get 10mm armoured xlpe if I were you, that will let you run the garage on a 50a breaker, or 6mm will give you 32a. You don't need to use any conduit or extra pipe, if it only runs under slabs, thats good enough mechanical protection, just cover it in warning tape
6mm will prob be fine as I don't plan on doing any major work like welding in the winter, nor do I plan on running anything like a 3 phase supply for welders etc, everything I use will be run off a 13A plug max. The pipe into the garage is already under the path as it was put in before the concrete for the base and path was laid down, around the outside of the house will the cable be ok just clipped to the wall or does it need to be run inside a cover? as the plan is to have the work signed off at some point. As I said in the first post I will be having my sparky mate help me some for of it, but I want to get the cable and sockets and get some of it in place before he comes to help finish it off. thanks very much for all your help Karl
Clipped to the wall is fine using cleats, probably number 7s. Keep an eye out on ebay, often get offcuts of armoured and cleats on there, can be quite expensive from a wholesalers.
cheers, Ill keep a look out, Screw fix seemed pretty cheap though so even if I end up paying full price its not too bad,
