Installing new 13A socket next to existing socket

[Sparky54]

We have a dual 13A socket on the ring main on the bedroom wall but, thanks to new technology, now need additional sockets. I would prefer not to use an extension block and would prefer to fit another dual immediately alongside it. Does that need to be wired as a series connection in the ring? That ring currently has one SFS and fan wired as a spur.

 

[ebee]

If that socket has a spur on it (one twin or one single socket or one fused connection unit) then no you should not use another spur on it to add anything but you can extend the ring so that your new socket (twin or single) is now on the ring. If your existing has no spur on it then yes you could spur your ne socket from it but you could also extend the ring instead for your new socket, the choice is yours. If you do extend the ring and your existing socket has no spurs then you could use both in future to spur off if you like. Only one caution, with a ring final circuit it is best to contain most of the circuit load within the middle one third section (as measured in the cable run length) or approx evenly over the whole circuit.

 

[JohnW2]

If that socket has a spur on it (one twin or one single socket or one fused connection unit) then no you should not use another spur on it to add anything but you can extend the ring so that your new socket (twin or single) is now on the ring. If your existing has no spur on it then yes you could spur your ne socket from it but you could also extend the ring instead for your new socket, the choice is yours. If you do extend the ring and your existing socket has no spurs then you could use both in future to spur off if you like.

I agree with all that.

Only one caution, with a ring final circuit it is best to contain most of the circuit load within the middle one third section (as measured in the cable run length) or approx evenly over the whole circuit.

Whilst that is conceptually theoretically true (but see below re details), I doubt very much whether the additional socket the OP wants for 'new technology' will be asked to carry any appreciable load.

As a matter of detail, in the common situation of Method C 2.5mm² cable, it's actually about two-thirds, not one-third. In that situation, even in in the 'worst case' (32A load applied at one point on ring), the current in the short leg of the cable would only exceed it's CCC (27A) if 'the point' were within about 16% (of total ring length) from one end of the ring - hence no arrangement of loads (totalling ≤32A) within the "middle 68%" of the ring could result in more than 27A flowing in any cable.

Kind Regards, John

 

[RandomGrinch]

We have a dual 13A socket on the ring main on the bedroom wall but, thanks to new technology, now need additional sockets.

I'm wondering how much of this 'new technology' may only require a charger plugging in?
Double sockets with four USB power outlets are common.
It might not be an easier job than installing an extra double socket, as the backbox may need to be deeper, but it could be a neater solution than multiple "wall warts"?

 

[EFLImpudence]

If that socket has a spur on it (one twin or one single socket or one fused connection unit) then no you should not use another spur on it to add anything

To be accurate, you may add another spur from the ring socket; what you should not do is extend the existing spur without overload protection (protecting everything on the spur) or, of course, using appropriately sized cable from the ring socket.

 

[JohnW2]

To be accurate, you may add another spur from the ring socket; what you should not do is extend the existing spur without overload protection (protecting everything on the spur) or, of course, using appropriately sized cable from the ring socket.

Very true,. I admit I didn't read that carefully enough - I agree with you but not (as I implied) with ebee.

Kind Regards, John

 

[SUNRAY]

Never used one but would this help:

Treble Converter Socket 2 to 3 Gang Double to Triple Electric 13 Amp Plug Outlet | eBay

TWO TO THREE GANG CONVERTER SOCKET. Each Socket has its own Rocker Switch. Supplied with 2 x M3.5 Screws to fit existing wall box. High Quality Products at Great Prices. AND Personal Friendly Service Too!

www.ebay.co.uk

 

[RandomGrinch]

Never used one but would this help:

Treble Converter Socket 2 to 3 Gang Double to Triple Electric 13 Amp Plug Outlet | eBay

TWO TO THREE GANG CONVERTER SOCKET. Each Socket has its own Rocker Switch. Supplied with 2 x M3.5 Screws to fit existing wall box. High Quality Products at Great Prices. AND Personal Friendly Service Too!

www.ebay.co.uk

Or even a four way! :

Socket Converter

Are you running out of plug sockets in your home? Instantly create extra space to power more devices simultaneously with this socket converter. It turns a one plug socket into a four gang adaptor. An accessory like this is great in the office for simultaneously powering a laptop, tablet...

www.toolstation.com

Although every triple socket converter I have seen has a 13A fuse built-in, to protect all three sockets.
The one in your link doesn't seem to have that?

 

[SUNRAY]

Or even a four way! :

Socket Converter

Are you running out of plug sockets in your home? Instantly create extra space to power more devices simultaneously with this socket converter. It turns a one plug socket into a four gang adaptor. An accessory like this is great in the office for simultaneously powering a laptop, tablet...

www.toolstation.com

Although every triple socket converter I have seen has a 13A fuse built-in, to protect all three sockets.
The one in your link doesn't seem to have that?

OK, I must say I've never knowingly dealt with any of them so can't comment on fuses etc other than just looking at MK info ( https://www.tlc-direct.co.uk/Technical/DataSheets/MK/Sockets.pdf ) which mentions:

13A Replacement fuses
(3 gang socket outlets only) 610

does it use a special fuse for the job or does it mean they're only fitted in the tripple? I'd be surprised if they'd imply a BS1362 isn't suitable.

 

[JohnW2]

Although every triple socket converter I have seen has a 13A fuse built-in, to protect all three sockets.

Same here, and I suppose that's consistent with the fact that every 3-gang socket (not 'converter') I've seen has also had a fuse.

The one in your link doesn't seem to have that?

I agree, it doesn't seem to - but, as above, I've never seen that before.

Kind Regards, John

 

[SUNRAY]

It was simply the first hit I had on google, I didn't look at detail other than the screwholes fitting a bouble box.

It's good to learn these things.

 

[ebee]

I agree with all that.

Whilst that is conceptually theoretically true (but see below re details), I doubt very much whether the additional socket the OP wants for 'new technology' will be asked to carry any appreciable load.

As a matter of detail, in the common situation of Method C 2.5mm² cable, it's actually about two-thirds, not one-third. In that situation, even in in the 'worst case' (32A load applied at one point on ring), the current in the short leg of the cable would only exceed it's CCC (27A) if 'the point' were within about 16% (of total ring length) from one end of the ring - hence no arrangement of loads (totalling ≤32A) within the "middle 68%" of the ring could result in more than 27A flowing in any cable.

Kind Regards, John

Hi John, yes agreed. I was adding the gen caution that it is good practice to put the heaviest loading on the middle third portion or spread pretty equally around the ring as a general concept. The heaviest loading by actual loading and percentage of time that loading occurs for too. As I said it is a generalisation and a sort of "back of a fag packet" guess usually suffices in most instances. It would not, for example, be a good idea to run it like a radial then at the far end bring a long leg back to the origin, that would be a not so well designed ring approach. And yes I think with the OPs question the actual loading would probably be not much. However, others referring to this at a later date might be tempted to just add some more significant loads willy-nilly

 

[Sureitsoff?]

Or even a four way! :

Socket Converter

Are you running out of plug sockets in your home? Instantly create extra space to power more devices simultaneously with this socket converter. It turns a one plug socket into a four gang adaptor. An accessory like this is great in the office for simultaneously powering a laptop, tablet...

www.toolstation.com

Although every triple socket converter I have seen has a 13A fuse built-in, to protect all three sockets.
The one in your link doesn't seem to have that?

4 way converter pictured has a fuse above the third socket

 

[JohnW2]

As I said it is a generalisation and a sort of "back of a fag packet" guess usually suffices in most instances.

I totally agree - and, as I said, I would personally say that a reasonable "... 'back of a fag packet' guess usually suffices in most instances " would be to say that one should try to keep most of the load within the middle two-thirds of the ring.

It would not, for example, be a good idea to run it like a radial then at the far end bring a long leg back to the origin, that would be a not so well designed ring approach.

Indeed - although, even then, it is (with Method C) only that first ~16% (of total ring length) in which one has to try to avoid 'very large loads' (for 'fairly long periods of time'), and anything up to 27A loading of that part of the ring (for an indefinite period of time) would obviously be OK.

In my (limited) experience, the closest one gets to a potential problem is when the CU is in a utility room (or kitchen), with a ring supplying WMs, tumble dryers and goodness knows what else in that room, but also wandering off to also serve other rooms. In that situation, those 'large' loads in the utility room will be connected very close to one end of the ring.

Having said all that, I suspected that it would be extremely unusual for the theoretical issue we're discussing to ever be a significant problem, although I accept that that does not mean that one can, of should, ignore it.

Kind Regards, John.

 

[ebee]

No John it is not usually a problem. More theoretical. But if you endeavour to make a first approximation using the middle third and/or spread about evenly so to speak you are unlikely to wander that far off the mark both regard possible loading and actual real life too that it is getting anywhere near a likelihood. I did say more of a back of a fag packet approach (I doubt anyone goes to great lengths planning/measuring or unduly worrying about it).

However I think many of us would try to avoid an "all at one end" scenario