Kitchen wiring alterations

[carlylad]

Hi there
Just having my kitchen layout altered to add an integrated dishwasher will it be OK to just add another socket into the 32a ring main supplied by 2.5mm t&e cable
My free standing washer and tumble dryer are currently on a double switched socket at the back of the appliances under the counter so it would be easy to break into the circuit and add another socket as I don't want to have to put a spur and have to put a switch above the worktop. Will I be OK with the loading I've uploaded layout drawings if it helps

 

[ericmark]

Are you asking about rules or if likely to cause a problem?

Rules say any fixed appliance over 2kW should have a dedicated supply.

In real terms likely no problem.

 

[Taylortwocities]

Should be fine. My advice is not to have the socket behind the appliance.

1. There may not be enough room behind (!)
2. Its a right PITA if the fuse goes or you need to switch it off in a hurry.

Put socket in an adjacent cupboard = under sink or (better) have a switched fuse above and a flex outlet behind the dishwasher.

 

[PrenticeBoyofDerry]

It would be okay to either extend the ring final circuit or spur from it.
But you can only spur from a socket that is on the true ring, not from an existing spur, the only occasion a spur can be spurred from, is when a fused connection unit is located at the intersection of the ring final socket to the first spurred socket, then sockets can be added from that socket, but you will be restricted to a maximum of 13A for the total load on this part of the circuit from the fused connection.

Intergrated units, also means that any socket outlet behind it becomes difficult to access, and the requirements permit only accessible accessories are installed, so they can be maintained, inspected and tested, you would also really want to be able to isolate the appliance, without having to manhandle it before you can disconnect. But I guess worse case, would be isolate at the board.
NB. That any newly buried cable if less than 50mm from surface and not mechanically protected most have 30mA RCD protection as should any newly installed socket outlets.

 

[carlylad]

The hob and oven have their own supply looks like a 6mm t&e with 16amp MCB from RCD protected fuse box I was just concerned about the loading on the ring but don't want a bank of switches above worktops but this will also be supplying the integrated fridge freezer which will be on a switched socket in the top of the carcass unit
as you can see from the layout there are no adjacent cupboards apart from the one under the sink and would think not a good idea to have under sink wastes etc so my only way I could see was to break into the existing ring and incorporate the new socket into the ring and not as a spur and have this socket t the back of the washer there is room its more the loading I was concerned with as I do intend to do some spurs from the ring for under cupboard lighting which I would have put on fcu above wall cupboards hidden by the top plinths or just a standard switched plug socket I do have a spare slot in my CU so could add another radial circuit for the washer dryer and dishwasher but adding a circuit then
Becomes notifiable doesn't it

 

[ericmark]

View media item 70952 Looked at the plan can't see dish washer as Taylortwocities says you want assess to all sockets also of course free air for cooling.

All fuses produce heat and there is a fuse in the British 13A plug so it needs free air around it to cool. With a FCU because it is larger and built into the wall it is more able to dissipate the heat into the wall so free air is not as important.

I would say with washing machine you need a means other than the washer its self to quickly switch it off. I have seen the result when the weights come loose and also in older days when the floor anchor bolts came loose and it does not take long to destroy anything near it.

However the tumble drier, freezer, fridge, dish washer are no were near the problem and there is enough time to open cupboard and empty to reach the switch it isolate for maintenance.

However once you put a grid switch to work one then why not have it work the rest? The problem with the grid switch is the switches are rated 20A so although you may have a pair of 2.5mm² cables feeding the switch after the switch fitting a double socket means the switch could be overloaded although the cable could also be overloaded for cable to be damaged needs time and on average it's not overloaded for long enough but this does not apply to switch.

View media item 70951 As I can't see if you have a dedicated ring for kitchen or if part of general house ring from picture I can't really say if OK or not but the real problem is not dish washer it is washing machine and tumble drier.

1) Washing machine does need readily assessable isolator.
2) Tumble drier works for an extended time so should have dedicated supply.

With kitchen ring you can really think of it as a dedicated supply but if general house ring then consideration on how close to consumer unit and other demands from rest of house. Diagram does not show this.

 

[carlylad]

Aggh I see what you mean from the drawing you can't see where dishwasher is located
It is a slimline one going to be located next to the washing machine under counter under the sink draining board

 

[carlylad]

ericmark
This would be a dedicated ring main to kitchen only
The cu unit is located in understairs cubby in open plan dining room next to kitchen no doors between the 2 rooms so easilly accesible for emergency or for servicing purposes
This is on a 32amp MCB in an RCD cu unit if it explains any better

 

[ericmark]

Yorkshire so adding a socket into an existing ring no not notifiable. It would be here in Wales as a kitchen but not in England any more.

Put a heavy load in centre of a ring and both legs will share load reasonable equal so only real problem is the breaker may open in other words fails safe.

However need the consumer unit one leg will take the majority of the load so the cable rated around 20A can be overloaded.

Following rules to letter it says over 2kW and not portable i.e. over 18kg has to have it's own dedicated supply so items like oven and immersion heater have their own dedicated supply. In theory this should include washing machine, tumble drier and dish washer. In practice the washing machine and dish washer does not take long to heat water and once water is heated does not use much power so in practice not really a problem.

The tumble drier however is another story this can take full 2kW for 90 minutes so same as immersion heater and worse then oven (assuming oven under 3kW).

However with a dedicated kitchen ring unlikely to be a problem as can't get close enough to CU to cause an overload. As I have said you have not given the info required to make a judgement.

 

[ericmark]

You posted while I was writing seems no problem then.

 

[carlylad]

ericmark
Sorry if I'm being thick so do you think there is no problem with loading if I add socket into ring or if I did put a dedicated supply on a 2.5mm radial could the Isolator switch be next to the cu unit on the wall in the next room instead of in kitchen but if I was having to go to cubby to switch isolayor switch it would be just as east to flick off the MCB to isolate
Would this seperate supply need to be a 2.5 km with 16a or 32 a mcb

 

[EFLImpudence]

will it be OK to just add another socket into the 32a ring main supplied by 2.5mm t&e cable

Yes.

 

[PrenticeBoyofDerry]

so do you think there is no problem with loading if I add socket into ring

I can't see an issue

or if I did put a dedicated supply on a 2.5mm radial could the Isolator switch be next to the cu unit on the wall in the next room instead of in kitchen but if I was having to go to cubby to switch isolayor switch it would be just as east to flick off the MCB to isolate
Would this seperate supply need to be a 2.5 km with 16a or 32 a mcb

On a radial circuit using 2.5mm T&E, you would not be able to use a a device to protect the cable that is greater than the safe current carrying capacity of the cable, 2.5mm has a maximum rating of 27A so 25A (generally difficult to get hold of) 20A or 16A breakers would be used. You could install 4.0mm T&E which can then be protected by a 32A breaker. I would be happy in this instant that the MCB would be a suitable means of isolation.
Installing a new circuit does require notification though.