UK Wiring Question?.

saltyseadog · 14 Nov 2014

In my kitchen/dining room, all the built in wall sockets are on the external facing wall. On the partition wall opposite, which has the living room/hall/stairs on the other side there are no built in sockets. As I have my fridge and a tropical fish tank on that kitchen/dining room wall it means that I need to have an extension cable running from a socket on the back wall, up and over the top and down to the other side. However, the Honeywell master control box for the old back boiler heating system was previously on that wall which had a wire coming from the roof down through a piece of external trunking and into the control box. Earlier this year British Gas installed a new boiler system for me under the free government scheme for pensioners. They connected the master controls for the new boiler to the wires in the hall passage where previously the Honeywell thermostat control for the old boiler had been placed and in the kitchen they had removed the master control box and dead ended the wires from the roof into a covered over junction box.

My question is, would it be okay for me to connect a 13amp socket to the wires inside the junction box in order to run one or more of the appliances mentioned above or would this overload it as I am guessing it is connected to the lighting circuit breakers?.

Taylortwocities · 14 Nov 2014

It would be very unusual for the (old) boiler to be powered from the lighting circuit.
If it were, you should not put a 13A socket on the lighting circuit as the overload protection on that circuit is 5 or 6 amps.

It is very likely that it is a spur from the ring final. Do you have tester/multimeter.?/

You first need to check if it still live, and then find out which circuit it is on (by turning the MCB/removing fuses one at a time in your fusebox.)

NOTE: if you have the old rewireable type fuse board, you must turn off the MAIN SWITCH when removing/replacing the fuses.

Hope this helps.

PrenticeBoyofDerry · 14 Nov 2014

You need to do a little investigating.
Firstly what CSA is the cable?
Is there an earth conductor present?
What size device/fuse is protecting this cable/circuit?
Is there RCD protection present on this circuit, as a new socket would require this?

saltyseadog · 16 Nov 2014

PrenticeBoyofDerry said:
You need to do a little investigating.
Firstly what CSA is the cable?
Is there an earth conductor present?
What size device/fuse is protecting this cable/circuit?
Is there RCD protection present on this circuit, as a new socket would require this?

The cable is 3cored, black-red-earth of the flat grey type like cooker wire I would reckon about 5-6mm. If I am correct in my assumption of the test I did below it is on a 32amp circuit. Earlier this year I updated the fuse box to a 17th Edition one when I had a dedicated connection to an electric shower I installed and it has the RCD protection you mention.

I decided to take a chance to resolve this and turned off the circuit breakers at the box for everything except the cooker. I then hooked up a socket to the 6mm 3 core wire left in the box. I took a lamp and plugged it into the socket and switched on the electric again and turned on the lamp which worked okay. I waited a couple of minutes but it stayed on and nothing tripped. I then turned off the downstairs lighting tripswitch, lighting went off but lamp stayed lit. I then turned off the upstairs lighting, upstair lights off but lamp stayed on. I then turned off the sockets and the lamp went off as well. It would appear that the wire is connected to the socket circuit after all or am I wrong?.

Taylortwocities · 16 Nov 2014

saltyseadog said:
I then turned off the sockets and the lamp went off as well. It would appear that the wire is connected to the socket circuit after all or am I wrong?.

It would seem that the cable is connected to the socket circuit, so you should be ok to put a 13A socket on there. Easy job!

ericmark · 17 Nov 2014

Likely no problem but the cables may be feeding some other socket already either before or after the point you have tested and unless you investigate fully you could end up with an unfused spur from and unfused spur.

So although likely you can fit a fused connection unit and from that as many sockets as you like until fully tested you can't be certain that's the case.

Seem to remember fish tank and freezer which should not be a large load but it would be wrong to say it's OK without warning it's not 100% certain.

Taylortwocities · 17 Nov 2014

I tried to qualify my reply by saying

Taylortwocities said:
It would seem that the cable is connected to the socket circuit, so you should be ok to put a 13A socket on there.

As with all electrical work - There are a number of things that need to be done to check before, and tested after the installation.
But I try not to do a BAS and provide a list of 20 manuals that have to be read beforehand

ban-all-sheds · 17 Nov 2014

Taylortwocities said:
As with all electrical work - There are a number of things that need to be done to check before, and tested after the installation.
But I try not to do a BAS and provide a list of 20 manuals that have to be read beforehand

So people just have to be struck by inspiration to realise that there are a number of things that need to be done to check before, and tested after the installation?

saltyseadog · 17 Nov 2014

ericmark said:
Likely no problem but the cables may be feeding some other socket already either before or after the point you have tested and unless you investigate fully you could end up with an unfused spur from and unfused spur.

So although likely you can fit a fused connection unit and from that as many sockets as you like until fully tested you can't be certain that's the case.

Seem to remember fish tank and freezer which should not be a large load but it would be wrong to say it's OK without warning it's not 100% certain.

My house is an ex-council house I bought approx 15yrs ago. The wire in question was as stated in my op previously connected to the Honeywell control for setting the timer and manual or timed operation of the old back boiler heating system and the British Gas crew who installed the new system disconnected that unit and capped the wires inside a socket sized box they fitted to the wall. The control for the new heating system they fitted to the wire in the hall which previously was connected to the Honeywell thermostat unit used to control the house temperature. What are the chances of the electricians who fitted the old boiler system approx 25yrs ago fitting it to an unfused spur?.

Taylortwocities · 17 Nov 2014

When the old Honeywell box was there, was there a fused isolation switch next to it?

saltyseadog · 17 Nov 2014

Taylortwocities said:
When the old Honeywell box was there, was there a fused isolation switch next to it?

Yes there was, in fact I think it is the base of that box that is left on the wall with the dead ended wires in it. I think they just replaced the front part that held the fuse with a blank cap. Does this help?.

Taylortwocities · 17 Nov 2014

OK, so there was an FCU there for the old back boiler systaem.
How many wires in that box?
If three, it probably means that it is a spur from the ring (socket) circuit. It is possible that there is another FCU somewhere - but I would think that you would be OK to put the socket on there (subject to the usual checks, testing, RCD protection etc).

saltyseadog · 18 Nov 2014

There are three wires in box. It is a flat grey cable the same gauge I think as cooker cable with a red - black - and solid earth core inside.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

UK Wiring Question?.

Similar threads