# Wiring a 2nd plug socket



## Pvt_Ryan (25 Feb 2011)

In my garage I currently have one plug socket and want to add a 2nd at the otherside of the garage.

Should I:
A) run a 2nd wire from the socket back out and then into the 2nd socket (so the sockets are wired serially)
or
B) Cut the existing wire where it comes into the garage, insert a 30amp splitter then connect the new socket to that (so the 2 in the garage woud be in parallel).
or
C) It doesn't actually matter either is ok.

Option B is my prefered option as it uses less wire to connect up the 2nd socket.

Regards,

Ryan


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## DeanN (25 Feb 2011)

Where does the cable originate from? Is it part of a house circuit, or run from a consumer unit on its own circuit.


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## Pvt_Ryan (25 Feb 2011)

House circuit.


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## Dibs-h (25 Feb 2011)

Pvt_Ryan":1m5s72ws said:


> In my garage I currently have one plug socket and want to add a 2nd at the otherside of the garage.
> 
> Should I:
> A) run a 2nd wire from the socket back out and then into the 2nd socket (so the sockets are wired serially)
> ...



The socket in the garage - does it go back to the Consumer unit in the house & it's own fuse\breaker? Or is it part of an existing circuit, i.e. same breaker\fuse as the downstairs sockets?

You say the socket has 1 wire coming to it - that sounds like a spur to me. In which case you can't run another cable from that into another socket, i.e. in series. Last time I looked at it - you can't run a spur from a spur!

For now - I'd suggest you just use an extension reel - that's what they're made for & wind it out fully. You really need to investigate the wiring that comes out to the garage, before doing any changes. Sod BC - it's more so you don't burn your house down.

Sorry if it's not quite the answer you wanted.

Dibs


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## Pvt_Ryan (25 Feb 2011)

It's part of an existing circuit, the same breaker\fuse as the downstairs sockets.


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## DeanN (25 Feb 2011)

As above, if its part of the downstairs mains circuit, and only has a single wire coming into it, then its likely to be a spur off another outlet. Try tracing the incoming cable back into the house, and determine where it's from.

Best approach would be to have a seperate circuit off the house consumer board, with a mini board in the garage.


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## Pvt_Ryan (25 Feb 2011)

I'll see if I can though I think it goes under the floor in the house and as I rent that might be going a bit far.

Why can't I run a spur from a spur surely running an extension cord is practically doing the same thing? I just hate wires trailing along the garage floor hence the want to add a second wall socket.


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## DeanN (25 Feb 2011)

If its rented, then check with your landlord first. Its the landlords responsibility to ensure the electrics in the property meet current regs, and should have the paperwork to prove this. I'm guessing not though, as the circuit outside should be on its own breaker.


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## Pvt_Ryan (25 Feb 2011)

The landlord is fine with me doing bits and pieces within reason. As to the regs well I don't want to bring up the 1st socket as if it didn't meet the regs the "solution" would be to cut the cable, and I'd rather have it than not.

The garage is attached to the house (no door between them but they share a common wall) if that makes a difference.


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## myturn (25 Feb 2011)

Pvt_Ryan":qui1e7v2 said:


> I'll see if I can though I think it goes under the floor in the house and as I rent that might be going a bit far.
> 
> Why can't I run a spur from a spur surely running an extension cord is practically doing the same thing? I just hate wires trailing along the garage floor hence the want to add a second wall socket.



You are essentially turning a single socket on a spur into a double socket on a spur, albeit the second socket is located separately from the first.

In practical terms I don't see any difference safety wise between replacing your single socket with a double or adding another single off the back of the first.
If you were then to replace both singles with doubles this would be a different matter with the risk of overloading the spur so this should not be done unless the spur itself is fused.

So of your two options I'd say either will do, but to avoid overloading the spur (and tripping the house ring) I would install a breaker on entry to the garage and run your garage spurs off that.


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## Pvt_Ryan (25 Feb 2011)

Sorry the 1st is a double and I am adding a 2nd double. (The "one socket" in the 1st post was perhaps confusing)

Maybe I am stupid but I don't understand how this is different to adding a 4way adator into a single socket.

I do however want to be safe / follow best practices if possible hence the post here.

EDIT: I should point out I don't have very much in the way of powered equipment and almost nothing that is "always on".
This is to power a bench grinder, lathe & bike battery charger (the charger being almost always on).


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## myturn (25 Feb 2011)

Pvt_Ryan":18wyz2wa said:


> Sorry the 1st is a double and I am adding a 2nd double. (The "one socket" in the 1st post was perhaps confusing)
> 
> Maybe I am stupid but I don't understand how this is different to adding a 4way adator into a single socket.
> 
> I do however want to be safe / follow best practices if possible hence the post here.


A 4-way adapter will have a 13amp fuse in it to prevent overload. 

Double sockets are not fused so there is nothing to prevent overloading the cable.

So best thing is to install a single fuse/breaker on entry to the garage and take a spur off that to each socket. This is essentially your option B with the addition of a fuse.


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## Pvt_Ryan (25 Feb 2011)

ahh ok i understand now..

is a single fuse/breaker dear? what capacity should it be? 30amp?


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## Pvt_Ryan (25 Feb 2011)

Would this

http://bit.ly/ehbiAm
and 
http://bit.ly/ijsmk6

do?


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## myturn (25 Feb 2011)

The fuse box will do, but the other link is to a switch which you don't need.

The box comes without breakers and as you are running a spur it should have a 20A fuse (30A is for a ring), so the breaker you want is the "Wylex 20A Circuit Breaker" (couldn't get the link to it on B&Q to work).


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## cambournepete (25 Feb 2011)

If you've already got an extension reel, why not just use that , but route the cable (fully extended) across the ceiling/loft space of the garage?


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## Pvt_Ryan (25 Feb 2011)

@myturn Thanks, I take it I need 2 breakers one per double socket?

@pete I use the extension reel round the house for other things round the house as well and for the vacuum to clean the cars so i dont want to have it routed like that.


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## cambournepete (25 Feb 2011)

Ryan,

I have in the loft of my garage gathering dust a power strip rescued from a scrapers lab bench. 2xdouble sockets, 2x4 way blocks, on a lead with a 13a plug.
It's yours if you want it.


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## Pvt_Ryan (25 Feb 2011)

Thanks for the kind offer Pete but I'd rather hard-wire it in, additionally this way it doesn't tie up a socket at the other end.


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## myturn (25 Feb 2011)

Pvt_Ryan":3ni0guwr said:


> @myturn Thanks, I take it I need 2 breakers one per double socket?


No, 1 breaker to supply both sockets, a spur should only take a 20A load so as not to exceed the capabilities of the cable feeding it, which will be 2.5mm.


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## matt (25 Feb 2011)

Why not change the first socket to a 3-way and have an extension lead cable-clipped round the wall to where you want it and simply plug it into the 3rd outlet of the first socket.


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## theartfulbodger (25 Feb 2011)

I fitted a 4 gand and a plug to a long bit of wire and then cable clipped it up the wall, across the ceiling and down the wall to where the bench is.

As I found out the thicker the cable the better to avoid overheating :shock: I'll be replacing it with "2.5 twin and earth" soon (if it's still called that? and if it's still legal for bodgers to buy it?)


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## petermillard (26 Feb 2011)

The usual way around the 'no spurs off a spur' reg is to install a Fused Connection Unit (FCU, like *this*) before the existing double socket, then take another spur off that FCU to wherever you want it i.e. one cable in, two cables out. Fair warning - I'm not a spark, but to the best of my knowledge the end result as described above will comply with the current regs. Don't forget that live cables require mechanical protection i.e. trunking or conduit - cables clipped to the brickwork won't comply.

The benefit of putting in a separate 2-way CU as was linked to earlier is that you could put the existing 2-gang socket and the new one each on their own breaker, so each leg could would be protected individually by a 16a breaker - though given the relatively light-weight usage the OP suggests (and perhaps I'm assuming too much, but I think the new socket is for convenience, not so you can run many devices at once, yes?) then personally I'd go the FCU route.

Might also be worth checking that the house CU has an RCD on the kitchen side btw, if that's where the spur feeding the garage comes from.

Cheers, Pete


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## Ateallthepies (26 Feb 2011)

As Pete said, the way to comply with the regs and with the least hassle is to put a fused spur on the cable that enters the garage before any sockets. Once this is done you can then install as many outlets as you want as the spurs 13 A fuse will protect the cable that enters the garage as long as the cable is not buried in insulation. 

Also there is nothing wrong with cables clipped direct to a wall in a domestic situation but extra protection is a good idea if they are likely to get bashed?

Steve.


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## myturn (26 Feb 2011)

A fused spur using an FCU is only rated at 16A.

So two FCU's are required for two sockets.

The easiest way is to use the Consumer Unit with a single 20A breaker feeding both sockets. 

You then have the benefit of a breaker which can be reset, fuses have to be replaced.


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## Pvt_Ryan (26 Feb 2011)

Thanks for all your input guys. You've given me a lot of info to digest. I think I'll most likely go the breaker route as it seems to be the easiest & has the added benifit I wont need to run into the house to cut the power to the garage. 

Might do the same for the lights for teh same reason but that'll be at a later date.


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## MickCheese (26 Feb 2011)

myturn":6pxdblrm said:


> A fused spur using an FCU is only rated at 16A.
> 
> So two FCU's are required for two sockets.
> 
> ...



You have confused me.

Is the fused spur plate not 13A? If it is placed first in the line as it enters the garage then every socket, regardless how many you fit, will have a ceiling of 13A. So if you have all of them in use at the same time the total load on the cable cannot exceed 13A.

Mick


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## Ateallthepies (26 Feb 2011)

MickCheese":1htaqcle said:


> Is the fused spur plate not 13A? If it is placed first in the line as it enters the garage then every socket, regardless how many you fit, will have a ceiling of 13A. So if you have all of them in use at the same time the total load on the cable cannot exceed 13A.
> 
> Mick



Correct, sort of. Even though a single 2.5mm cable can take up to 27 Amps or so when clipped direct, we have to take into consideration if that cable is run in insulation which can de-rate that cables power handling capacity by up to 50% in a worse case scenario.

Having that 13 A fuse will protect the cable under normal conditions as it will happily allow 25 A to flow for about half an hour before it blows which is about the cables rated capacity. It takes around 30 A before the 13 A fuse will blow within 400 seconds!

As I said elsewhere, fuses are terrible for protecting against overload currents and require many times the fuse rating to 'blow' instantly. The more current flowing above the cables rating before the fuse blows allows the cable to heat up. Add insulation to the mix and things change big time!

We really need to know how cables are run before adding load to them and failing that have to assume he worst case and de-rate them by half their normal current carrying capacity.

In reality thought adding an extra socket to a circuit and using it normally will not cause any problems no matter how the cables are run and whatever the size of 'fuse' used. But sparks have to factor in abuse when they design and install any circuit or modification and this is why factors such as cable size/length of run, thermal properties of the building and 'fuse' ratings are important. 



Steve.


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## petermillard (26 Feb 2011)

Pvt_Ryan":2v1fexrb said:


> Thanks for all your input guys. You've given me a lot of info to digest. I think I'll most likely go the breaker route as it seems to be the easiest & has the added benifit I wont need to run into the house to cut the power to the garage.


Fair enough, though you could use a switched FCU which effectively does the same thing. Whatever, *this one's* pretty good value as it comes with a 16A breaker for sockets and 6A for lights as and when the time comes.

Cheers, Pete


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## Ateallthepies (27 Feb 2011)

If you go the mini consumer unit route you still need to protect the single spured incoming cable. Having two sockets run off their own 16 A circuit breakers will potentially allow around 48 Amps to flow without the circuit breakers even thinking about tripping! Consider that a single 16 A circuit breaker needs 80 Amps for instant tripping or 30 A to trip within 250 seconds!!

Either use a spur with a 13A fuse or your mini consumer unit with a single 16A breaker then run all your sockets through whichever one. You could even go down to a 10A breaker if you want to be extra safe??

Have a good look round your house and see if there is a fused spur unit that is already feeding your garage socket. If there is then add sockets and lights to your hearts content as the cable will be protected (assuming the cable is in fact a 2.5mm?). You may not find a fused spur though and the garage cable will have been taken directly from an existing socket which is fine as only one item is allowed to be spurred without a fuse included. 

Steve.


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