Garage electrics advice please :) - making a ring circuit

Phate

Phate

Phate

Caporegime
Joined
1 Nov 2003
Posts
35,691
Location
Lisbon, Portugal
Hi all,

I will try as best I can to describe the current scenario, where I want to get to, and what I "think" is the way to get there, please correct me where you see fit! I am perfectly happy tackling most if not all DIY stuff, just cautious when it comes to home electrics

So in my garage (which is 2 floors below my building) I have a fuse box on the wall which has 4 cables coming out the top, I traced these and see it as

1 - Goes to 1 individual plug socket on the wall
2 - goes to a junction box which splits off to a light switch and a then a light
3 - goes to an individual plug socket which is on the ceiling to power the electric garage door
4 - is the supply from the building mains

So I am in the process of converting my garage into a home workshop for hobbying/home RC and modelling stuff. As such, I wish to place a significant amount of sockets on the walls as I want to have a number of tools plugged in ready to be used at any given time. I was advised by Dad to make it into a ring circuit (he knows a fair wack about home electrics)

Looking at diagrams of ring circuits, it needs to start to and from the fuse box on inidividual supplies.

So what I was thought was running cable from the socket on the ceiling down to the wall to where i want additional sockets, daisy chain them together, then complete the loop by running a cable coming off a new socket into the one which is already on the wall. Effectively joining 1 + 3 together.

See below for a crude diagram

UMLZl2y.jpg


Hope this makes sense in what I am trying to achieve :) - thank you in advance!
 
No that doesnt look right. To have a ring you would need to start and end on the same circuit.

so you would take a feed from the celing plug but would need to end back at the same rcd/mcb.

What your proposing will just result in the rcd/mcb not setting/working.

You could feed from that socket on the wall and run around the room and finish back at the fuse box in the same way as above.

y6tbdPx.jpg
 
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NoobCannon said:
No that doesnt look right. To have a ring you would need to start and end on the same circuit.

so you would take a feed from the celing plug but would need to end back at the same rcd/mcb.

What your proposing will just result in the rcd/mcb not setting/working.

You could feed from that socket on the wall and run around the room and finish back at the fuse box in the same way as above.
Click to expand...

Thanks :) That clears up the doubt.

So I can just run an additional cable into the same circuit breaker - easy enough!

Thank you :)
 
NoobCannon said:
Essentially yes. You would need to work out if the mcb/rcd is rated high enough for everything you plan to be using is all.
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NP - I can do that. While a lot will be plugged in it wont be in continuous use and almost never all at the same time :)

Thank you!
 
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What are you using for work benches etc?

I've just replaced my kitchen and the old units, while scruffy and the doors falling off, are structurally very good.

So I've taken them all down in one piece and chopped the work surface into decent lengths.

I'm going to build a few cabinets into my man cave for wood working and tinkering with electrics and a few in my garage for car building. Really useful if you can find someone tipping an old kitchen.
 
On the right side it will be a 3m or so of kitchen worktop with kitchen units fitted underneath. It's going to host the main tools (table saw, pillar drill, grinder etc) then on the far wall will be my workbench. I've got a roommate moving out so the desk I have in her room I'll move to the garage. That'll do for now. :)

I am into RC Modelling so mainly that. But also want to try my hand at electronic projects as well. All sorts. Will likely cram a 3D printer in there somewhere. :D

I bought new kitchen units and assembled those last week :)

The tops of the boards you see in the photo are from a dismantled IKEA cabinet. I plan on repurposing a lot of that into shelves and all sorts.

Happy to share more pics if interested
 
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Nice, it's going to make things much more fun when I get myself organised too.

I'm still building the new kitchen, routing the joints on the worksurfaces today but my bit is 8mm too short...

Mines all planned in my head, but it's like one of those puzzles where you can move one little square to make a picture. Once I've done the kitchen, I can clear the living room of kitchen stuff, then move my car parts out the man cave to build that and organise stuff.

Then clear the garage by organising that into the man cave. Then build that.

Then build the car and do whatever projects come up.
 
Hi Phate

I did something very similar in my garage. Can you confirm a few things?

1) When you use the term fuse box, do you mean small consumer unit?
2) If you look at the at the your main consumer unit in the house/flat this should have an MCB circuit where the garage can be isolated. Can you confirm this, also can you confirm if the garage circuit is RCD protected? It would also be useful to know what the current rating of these MCBs is (stated on the front) to help with design of your garage wiring?
3) You will need to verify that the garage consumer unit has an incoming earth of some description.
4) If you are extending a circuit it is imperative you know the diameter of the conductors (live and neutral) of any existing wiring. This is highly likely to be standard 2.5mm2 twin and earth cable but it is important you check/confirm.

Personally for doing home/DIY wiring I would recommend radial circuits as opposed to ring circuits (covered in the links below). It really comes down to what you think the maximum peak load you will draw from your plug sockets. Most stuff other than heavy corded power tools and electrical heater is relatively trivial but if you add up the watts of everything you intend to use in the garage at any one time that would be a good starting point. You can hence size the circuit in the same way you would size a PSU for a computer build (not the greatest analogy but perhaps useful)

Finally you need to understand how MCBs protect the circuit against electrical fire but are heavily dependent on being sized according to the wires in the circuit. If the MCB is sized for a 2.5mm2 ring circuit but someone has spurred off a socket with 0.75mm2 cable at some point in the circuit you will have problems as the MCB will not trip but (if put under sufficient load) the small diameter cable could heat up and cause a fire.

A couple of videos explaining ring and radial circuit.

https://www.youtube.com/watch?v=hZN6hiGLtrE

https://www.youtube.com/watch?v=At7AnMV7Xd0&t
 
In your diag I would put another double at bottom right corner - I have at least 10 doubles in my garage and sometimes I am looking for a spare socket as most of the tools are plugged in but not on and also behind things like pillar drill and shelf racking - mine was a empty room once so more sockets the better for what they cost.
 
DXP55 said:
In your diag I would put another double at bottom right corner - I have at least 10 doubles in my garage and sometimes I am looking for a spare socket as most of the tools are plugged in but not on and also behind things like pillar drill and shelf racking - mine was a empty room once so more sockets the better for what they cost.
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Oh yes what is in the diagram is not the full extent of all the sockets. I just quickly and crudely drew it to show what I was getting at :)

plan is (as you're looking at the garage)

- Left wall, 1 Double socket behind the shelving I put in which is where I will keep my RC Models. A charger will be left permenantly plugged in there with a long charging cable to reach any shelf and power for a compressor.
- back wall, 2 double sockets. This will be my ad hoc work bench, no tools in permanent spots here. So stuff like dremel usage, soldering iron etc
- right wall, 3 double sockets. On this bench will be. Pillar drill, table saw, grinder fixed down.

Thats the idea. Giving me 12 sockets overall.
 
Probably worth checking the local code in Lisbon Phate...Rings are something that we use in the UK, but would be considered very unusual and against code (if not dangerous to future owners) in the US for example.
 
Jez said:
Probably worth checking the local code in Lisbon Phate...Rings are something that we use in the UK, but would be considered very unusual and against code (if not dangerous to future owners) in the US for example.
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Will do Jez, however I know my apartment has rings in it. But will check with a local spark :)

EDIT: Scratch that, I thought my apartment did, but it doesn't. And just checking here https://www.legrandgroup.com/sites/...olutions/Guide_International_standards_EN.pdf - Portugal follows the German standard so its radial all the way,. Not ring circuit. Good call Jez.

Radial it is :)
 
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Glad someone raised that. Very good advice in this thread but UK-specific :)

Also wondering if your garage's CU has separate MCBs for the 3 things you described - sockets, door and light, or sockets and light, or just all off one breaker?

Always good to have at least lights on separate breaker. Helps when fiddling with wiring later - can have a lamp on while the lights are disabled. Or the lights on while the sockets are off!
 
Its got 3 breakers, 1 for each plug socket and 1 for the lights.

So as I am going radial, and code states no more than 8 sockets per fuse I will run 6 off of each giving me a bit of breathing room :)
 
Phate said:
Its got 3 breakers, 1 for each plug socket and 1 for the lights.

So as I am going radial, and code states no more than 8 sockets per fuse I will run 6 off of each giving me a bit of breathing room :)
Click to expand...

Not familiar with German regulations but I would expect the '8 sockets' per circuit is 8 double sockets, worth checking but sometimes useful to split your sockets over multiple radials in a space like a garage. Also per post #9 can you confirm the Amp rating of the MCB that the garage is on within your main consumer unit (fuse box) in your flat/house. It should have have a code on the front that you can Google to find out.
 
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