socket ring main tripped after adding spur

[Toolbox]

Hi Folks
Need more sockets in one of the bedrooms it only has one.I took a spur from this to feed x2 single sockets and one double does this mean I have 3 spurs for 1 ring main socket.Since doing this my ring main fuse has tripped x2 in last 3 hours.Any advice would be good thanks.

 

[Spark123]

Do you mean you have daisychained them? You cannot spur from a spur unless there is protection upstream such as a fused spur unit.
You could have an intermittant short on one of the sockets such as if you had caught a wire or the insulation is stripped back too far behind one of the sockets, but you need to sort out the spur situation first.

 

[oharaf]

Assuming you are on a ring you can only spur off for one single or one double socket, you will also need to have RCD protection.

If it is the MCB tripping then you have a short somewhere!!!

 

[sparkyspike]

Unfused spurs ned to be limited to one socket. Multiple sockets need to be protected by a fused connection unit.

This probably isn't the reason why your mcb is tripping, (unless you're using high loads - heaters etc) so please explain exactly what you have done.

Firstly, how do you know you are connecting into a ring?

Secondly, how have you tested the circuit to see that it is wired correctly?

 

[Toolbox]

Thanks folks I took a spur from the only main socket in the room I assumed this is on the ring main its a single plug with 2 leads in and 2 neutrals out I added a new feed and connected this to a single socket from this socket to another single socket and from this to double socket.This sounds like a daisy chain

 

[Toolbox]

More info The only test I done was to plug in a lamp and worked ok and visuallly checked wires to correct terminals.

 

[sparkyspike]

You can't assume that 2 cables means a ring. You need to check continuity between them to prove that both sides are connected at the fuse box.

Even if it is a ring, what you have done is dangerous. The cable you have used is not rated to 32A and cannot be used for multiple sockets.

If you don't know how to test circuits then you will need to call an electrician to do this for you.

Back to your problem of the mcb tripping - can you clarify what you have done exactly. 'Two leads in and two neutrals out' doesn't make sense.

 

[Spark123]

Aye - sounds like you have daisychained them.
You either need to look at making all of the sockets on the ring or fusing down before the first spur.
You also need to test the wires which you suspect to be on the ring as opposed to just guessing that they are part of a ring - if you continuity check the live to live, neutral to neutral, earth to earth at the first socket you should find each pair are closed circuit. If they are not then it is not a ring.

 

[Toolbox]

To check for ring main socket would I power of at fuse box and disconnect live wires at whats thought to be main ring socket and using dmm check the resistance across the 2 live wires and same for neutral and earth.
If this is main ring I can then only run 1 double socket of this

 

[Spark123]

Yep - it is probably a good idea to unplug everything from the circuit too whilst doing any testing as appliances may cause you to get misleading results.
You can only have one unfused spur from a ring final circuit. This can be a single socket or a double socket.
It can be a fused spur unit and you can feed all the sockets from that.
You could equally divert the ring to include all of the new sockets and have no spurs.

 

[Toolbox]

Did the following.
Powered off at breaker
At socket removed live wires and got resistance across them.
Refitted live wires and disconnected Neutral wires and got resistance across them
Never got resistance across earth wires.

Also found dodgy wire in socket this might exsplain the tripping.

Is this socket on the main ring??

 

[Spark123]

It sounds like it is, however you have an open circuit earth so unless you are comfortable with fault finding it call an electrician in.

 

[Toolbox]

Thanks for your help I will reduce daisy chain sockets down to one double socket only.I assume the earths are all connected in series how would I fault find this.

 

[Spark123]

I'd do it by disconnecting the 2 ends of the Ring in the CU, joining live to earth on one leg only, do resistance tests all the way around the ring.
Disconnect the join and join the other L&E together. Do the same again, by process of elimination should be able to get it down to a couple of sockets. A low resistance ohm meter is a good tool to use as the resistance figures should increase as we move away from the CU.

 

[Toolbox]

Thanks Spark123 I will give this a go. I have now only one double socket spur.
When I disconnect the rest of the daisy chain I found that when I had screwed the socket face into the mounting box. I had managed to catch and bare a wire. This was the cause of the ring fuse to trip.
Thanks again.