Extending Garage Wiring

[deemo]

Hi

I want extend the wiring in my Garage to add another double socket at the back of it.

The Garage is wired already with a double socket, Light switch and Fuse box which was professionally installed by home builder.

I can tell difference between live, earth etc Was wondering if i can extend the circuit by taking a supply from the 1st Double socket to the 2nd new one using the correct electrical wiring as advised.

I've not opened up the 1st double socket but can't think there will be any complicated setup.

A simple diagram or instructions would make me feel safer / better although i think i can take a rough guess of what needs to happen

Thanks

 

[deemo]

Think i found the answer just need someone to confirm

On this diagram i suppose that be my 1st socket and all i'm doing is adding the 2nd

So from 2nd would i got back to the consumer box or do i not need to work about ring circuit in garage

http://i69.photobucket.com/albums/i62/RFLighting/RingCCT.jpg

 

[plugwash]

Before we can advise we really need to know what the current setup in the garage is. Where is the garage powered from? is there a consumer unit in the garage? if so what fuses/breakers are in it?

 

[JohnW2]

On this diagram i suppose that be my 1st socket and all i'm doing is adding the 2nd ... So from 2nd would i got back to the consumer box or do i not need to work about ring circuit in garage

You probably don't need to bother having a ring in your garage. As plugwash has said, the crucial question relates to what is feeding the present socket. Is it connected straight to the garage CU (and to nothing else) and, if so, what is the rating ('amperage') of the fuse or breaker in the CU to which it is connected? ... and what sort of things do you envisage running from the garage sockets (i.e. what is the likely 'total load')?

Kind Regards, John

 

[deemo]

Thanks for the response i thought i'd mentioned most in 1st post anyway

There is a consumer Box in the Garage with two breakers which read B6 which is for Light Switch and B16 for the 1 double socket already in garage.

In terms of wiring from Consumer box goes a wire to the Double Socket.

I might as well tell you the use as it may affect the wiring used and breaker may need replacing.

I plan to run a Treadmill and a small Freezer + a heater in winter but they at other end from the original socket and it maybe i need to put up two double sockets

Just hoping thats a better solution then running an extension cable

 

[JohnW2]

Thanks for the response i thought i'd mentioned most in 1st post anyway

You did mention a fair bit, but not the most crucial which was:

...with two breakers which read B6 which is for Light Switch and B16 for the 1 double socket already in garage.

I plan to run a Treadmill and a small Freezer + a heater in winter but they at other end from the original socket and it maybe i need to put up two double sockets

Thanks. Assuming that the socket is wired in 'standard' 2.5mm² cable, you can, as you proposed, simply run a second (or, indeed, as many as you like) socket from that first socket, using the same size cable, without bothering to make it into a 'ring'.

The B16 breaker will limit you to a total of 16A across all the sockets. Depending on what sort of heater you have in mind, that could use most of that (a 3kW one takes 13A) and I have no idea how much the treadmill will use - do you know? Using 2.5mm² cable, you could change the B16 breaker to a B20 one, giving you 20A (provided only that what was supplying the garage CU was capable of supplying that).

If you needed more than 20A, and if supply to the garage CU could provide more than 26A (including the 6A for lighting), then it would get more complicated. You'd have to change the breaker, probably to a B32, and then either wire with 4mm² cable (including replacing the present wiring to first socket with that size) or turn it into a ring using 2.5mm² cable.

Kind Regards, John

 

[riveralt]

You can run as many double sockets as you want from the sole garage double socket - since it is just a radial circuit.
Assuming the current and the future wiring is 2.5mm ² T&E and clipped direct I would increase the MCB to a B20A.
By the way something is definitely wrong if you have a treadmill and heater in the garage - you're not working hard enough

 

[JohnW2]

By the way something is definitely wrong if you have a treadmill and heater in the garage - you're not working hard enough

Maybe (and, in fact, hopefully, from the point of view of current demand!) the two won't be used simultaneously

Kind Regards, John

 

[ericmark]

In 2008 the rules changed and now there should be a RCD on all sockets unless for something special like a freezer and then it would need marking freezer only.

Easy way is to use a RCD socket assuming cables are surface.

I am sure many don't bother with RCD protection but you have asked what should be done so we should at least tell you that new sockets should be RCD protected even if you don't do it.

 

[JohnW2]

In 2008 the rules changed and now there should be a RCD on all sockets unless for something special like a freezer and then it would need marking freezer only. Easy way is to use a RCD socket assuming cables are surface. I am sure many don't bother with RCD protection but you have asked what should be done so we should at least tell you that new sockets should be RCD protected even if you don't do it.

A valid point, but I strongly suspect that the 'garage CU' the OP has will have an RCD incomer.

deemo: does your CU in the garage have (in addition to the B6 and B16) and RCD/'main switch' with a 'test button' on it?

Kind Regards, John

 

[deemo]

Hi Guys

Thanks you've been very helpful. I don't think there is a RCD in the CU to make it easier i've added two pictures of CU and the actual current circuit

Looks like the Socket cable is 4mm as it's ticker then the light one which does look 2.5mm

 

[riveralt]

No RCD and to me that looks like 1mm ² T&E for the lights and 2.5mm ² T&E for the socket.
If you want to extend you are going to have to introduce an RCD into the circuit.
edited thanks to JohnW2

 

[plugwash]

Thanks you've been very helpful. I don't think there is a RCD in the CU

Indeed there isn't. having said that the system may be RCD protected further upstream. Do you know where the garage CU is supplied from?

 

[JohnW2]

No RCD .... If you want to extend you are going to have to introduce an RCD into the circuit.

Unless, that is, the whole garage installation is fed from an RCD protected circuit in the house.

deemo: do you know where the feed to that garage CU comes from (in your house CU?) and whether it is RCD-protected at the house end?

You could simply replace the first socket with an RCD socket and add as you please.

I don't really understand that. I don't recall ever having seen an RCD socket which provides an RCD-protected output for feeding further sockets, have you?

Achieving RCD protection in the garage (if the circuit is not already protected in the house) could be achieved by replacing the main switch in the garage CU with an RCD (- the usual solution, but some people might then moan about the lighting and sockets being on the same RCD), changing the B16 MCB to a B16 or B20 RCBO or by introducing a standalone RCD (an RCD FCU would not allow more than 13A) in the feed to the first of the sockets.

Kind Regards, John

 

[deemo]

No idea where CU is supplied from.

I've been lead to believe by the neighbours that all the garages on the estate are supplied from a common source and not from the House as all garages are detached from properties

This could be true as some peoples garage could be like 200 yards from their home on other side of road.

But if i can get away with i suppose changing the face of the 1st socket i suppose that works.

The clips on the light cable read 2.5 thats why i assumed it was 2.5