Spur off cooker switch?

[tonytinman]

I'm moving a cooker switch as it's located directly above where a new hob is going. When I removed the switch I saw it has two sets of twin and earth on the supply side of the switch.

Is this a common scenario? There is no electric shower or heaters. Could this be going to an old shower or immersion heater that is no longer there? What's the best way of working out where it's going?

Also, I need to crimp the supply cable to extend to where the new switch will be located. What's the best method of connecting these two twin and earth cables and running extra cable to the new switch. There's be no access as it's above the hob so will be embedded in the wall. I can't seem to find through crimps big enough to take two sets of 6mm twin and earth on one side.

Thanks.

 

[securespark]

Could there be two cooking appliances that are independently switched?

 

[ban-all-sheds]

Could this be going to an old shower or immersion heater that is no longer there?

What's the best way of working out where it's going?

What's the best method of connecting these two twin and earth cables and running extra cable to the new switch.

Replacing it.

There's be no access as it's above the hob so will be embedded in the wall.

Best not to have any joins.

I can't seem to find through crimps big enough to take two sets of 6mm twin and earth on one side.

They don't make insulated ones that big.

Why do you need to join 3 cables?

 

[tonytinman]

I can't seem to find through crimps big enough to take two sets of 6mm twin and earth on one side.

They don't make insulated ones that big.

Why do you need to join 3 cables?

Because on the supply side of the existing switch there are two sets of 6mm twin and earth. If I want to relocate the switch 300mm to the right, and keep the same configuration, will I not need to connect the two cables to one side of a connector and run another cable to the new switch from the other side?

 

[ban-all-sheds]

In which direction(s) do these cables, and the Load one, run relative to the switch now, and after the move?

Pictures would be useful.

 

[tonytinman]

Untitled

• tonytinman
• 9 Jul 2014
• 1

 

[PrenticeBoyofDerry]

Some investigation is required with regards to the extra set of cables, it could be a second cooking appliance, it could be for a socket, it could be for the extractor fan, so we need to solve that puzzle!

Ideally you would install a new length of cable between supply and new isolator and remove the existing box. But if you intend not to do that then you need to determine what the second set of cable are doing as it may require that isolation and that would then mean replacing that cable or configuring the circuit so the new isolator feeds back to the second set of cables, this could mean installing a second cable between new iso and the existing, then jointing up, you can use correctly rated terminal blocks and blank plate.
Then we need to conform to safe routing of cable and the required additional protection to buried cable less than 50mm in wall, so RCD or mechanical protection needs to be considered.

 

[tonytinman]

Thanks for all the advice guys.

My plan is to:

i. remove existing box so I'm just left with the 6mm feed from the consumer unit and the unknown 6mm T&E
ii. crimp and heat shrink two new 450mm lengths of 6mm T&E to both of these.
iii. put both of these extension lengths in trunking which drops 150mm and turns right 300mm (as in the diagram). this will move the cooker isolation switch away from the new hob
iv. fit both these cables into the new cooker switch in the same configuration as before
v. drop a new 6mm cable output from the new switch to the new cooker conecction point. again, channelled into the wall in trunking.

does this sound ok?

thanks again for the advice.

 

[securespark]

Could there be two cooking appliances that are independently switched?

 

[tonytinman]

Not entirely sure I understand the question. Perhaps it's so obvious I'm just not getting it. Do you mean is there another cooker?

 

[AndyPRK]

Exactly. Maybe it used to power a hob or oven.

Maybe it runs to another cooker switch which has been plastered over.

 

[rjm2k]

Put it this way, you haven't mentioned what is protecting this circuit at the consumer unit, that would be useful info. Once you know that, if you switch that MCB off at the CU, what else, other than the cooker stops working?

Is there anything in line with where the "extra" cable runs to ?

 

[tonytinman]

Put it this way, you haven't mentioned what is protecting this circuit at the consumer unit, that would be useful info. Once you know that, if you switch that MCB off at the CU, what else, other than the cooker stops working?

That was my next move.
To be honest, there's not a great deal it can be.
There's a combi boiler in that general direction and a single socket below worktop level. Think this was used to power the washing machine. Thinking about it now, I reckon it could be going to that.

All the same I think I'm going to have to resort to the earlier suggestion of hammer and chisel to be sure.

 

[AndyPRK]

Turning the MCB off and seeing what doesn't work is the first thing.
I thought you had already done this.

 

[tonytinman]

Nope. Not yet. It was 11 o'clock last night when I got the front off the switch and discovered the additional cable.
At that point, I sighed, gave up for the day, and went home.