Kitchen ring main on 20a MCB?

[bowgieman]

Hi,

Is it okay to have all kitchen appliances on one ring main on a 20amp mcb? I am planning on having a new kitchen installed with the built in appliances listed below together with the wattage, which all adds up to 12500 Watts. I will be getting a sparky in to do the work but I wanted to get an idea of the work that needs to be done and what my options are. Do I need to have 2 circuits and also change the mcb to 30amp? And what would be the costs?

Many thanks in advance.

Cooke And Lewis Single Oven CLEF3SS-C 13amp (not sure of the Wattage. Is this 13*230 = 2990?)
Microwave – 800W Heating, 1000W Grill
Fridge – CATA BIF77A 800W
Washing Machine 750W
Kettle – 3000w
Toaster – 1800w
Combi Boiler, Potterton Titanium 33E – 3amp – 720W
Gas Hob Ignition – 3amp – 720W
Cooker Hood – 3amp – 720W

 

[JohnD]

if you currently have a 20A circuit in your kitchen, it may be a radial circuit, not a ring. I think you have misread your washing machine, it is more likely in the region of 2500 to 3000W when the heating element is on.

the single oven is probably in the region of 2500W to 3000W.

20A for a kitchen is rather too low. It will only supply two large appliances at a time.

It is preferable to have a dedicated circuit for a large appliance such as a cooker. You could have a circuit installed which is capable of supplying an electric cooker should you desire one in future. This would cost extra though.

It is nice to have a dedicated circuit for the freezer, on its own RCBO, to help protect against the food thawing out if a fault elsewhere trips the RCD (or MCB). This would cost extra though.

 

[ricicle]

Only the electrician will tell you for sure regarding your set up but :-

A 20amp ring circuit is not a 'recognised' circuit.
A whole house on one 32amp ring circuit is not usually a problem but generally new design would probably see a seperate one for a kitchen especially with the splitting up of RCD circuits and supply retention.

 

[PrenticeBoyofDerry]

If you have the opportunity to update the circuits a minimum consideration would be 32A RFC or radial for kitchen appliances and a separate circuit for cooker/oven/hob.
I personally go cooker circuit, above worktop sockets, below worktop appliances. Separate circuit for fridge/freezer and boiler.

 

[winston1]

Hi,

Is it okay to have all kitchen appliances on one ring main on a 20amp mcb? I am planning on having a new kitchen installed with the built in appliances listed below together with the wattage, which all adds up to 12500 Watts. I will be getting a sparky in to do the work but I wanted to get an idea of the work that needs to be done and what my options are. Do I need to have 2 circuits and also change the mcb to 30amp? And what would be the costs?

Many thanks in advance.

Cooke And Lewis Single Oven CLEF3SS-C 13amp (not sure of the Wattage. Is this 13*230 = 2990?)
Microwave – 800W Heating, 1000W Grill
Fridge – CATA BIF77A 800W
Washing Machine 750W
Kettle – 3000w
Toaster – 1800w
Combi Boiler, Potterton Titanium 33E – 3amp – 720W
Gas Hob Ignition – 3amp – 720W
Cooker Hood – 3amp – 720W

Many of your loadings are completely wrong. A washing machine heater will be around 3000W, gas hob ignition tales very little maybe 1W, and a cooker hood maybe 50W and another 2 times 40W for built in lights. Just because something is fused at 3amps does not mean it consumes it. An 800W microwave refers to the output, its loading will be considerably more.

You are unlikely to have everything on at once. Put the oven on its own circuit and everything else on a 32amp ring.

 

[bowgieman]

Thanks for the replies.

The current 20amp radial circuit (2.5 T&E cable )currently feeds the combi boiler, washing machine and the worktop sockets. Is this okay or does it need upgrading to a ring circuit with a 32amp mcb?

The new Built in Oven, Microwave and Fridge would be located away from the worktop area in a larder cabinet, so I could possibly have the three appliances on a new 32amp circuit? Would this be Ring or radial? Which would be better?

Also if I were to get the 20amp mcb upgraded to 32amp and also have an additional 32amp mcb installed for the new circuit, I was wondering if the Fused Connection Unit can handle this. Does iot have a maximum capacity?

Thanks

 

[bowgieman]

Many of your loadings are completely wrong. A washing machine heater will be around 3000W, gas hob ignition tales very little maybe 1W, and a cooker hood maybe 50W and another 2 times 40W for built in lights. Just because something is fused at 3amps does not mean it consumes it. An 800W microwave refers to the output, its loading will be considerably more.

You are unlikely to have everything on at once. Put the oven on its own circuit and everything else on a 32amp ring.

Thanks for the clarification winston1. I wasnt sure what the wattage capacity was so I just guessed at the maximum. Would it be okay if I had the oven, microwave and fridge on its own ring circuit?

 

[ericmark]

What is or is not required will depend on how close to the regulations the electrician wants to go.

1) The ring we assume a ring will have a 20A load in centre the rest even throughout the ring be it on a 32A MCB or 20A MCB so there is very little point using a 20A MCB for a ring. If 20A likely a radial rather than ring so 20A is the max.

2) Items over 2kW fixed should have a dedicated supply so oven (electric), hob (electric), washing machine, tumble drier, and dish washer should all have there own supply. Often only oven and hob have dedicated supply but this is down to the electrician doing the work.

3) Kettle although over 2kW is not fixed so that does not need a dedicated supply. If the rest are wired correct then kettle is the biggest load and a 20A supply is ample only when items which should have a dedicated supply are connected to general kitchen sockets is there a problem.

4) Often a so called kitchen ring is not really a kitchen ring but two conductors in parallel. Two cables are used as the grid switch will only take 2 x 2.5mm² not 2 x 4mm² it's the physical connection that means two cables and because not really a ring they are not controlled by ring final rules so washing machine can be powered from it. But this is again up the the electrician doing the work to decide how to class it.

A washing machine rated at 2.6kW will run from a B6 MCB it should not work but it does because the time when heater is on is so short. A B4 MCB will trip. However a tumble drier is very different because of the time the heater runs for. So likely all of what you have will run from a 20A MCB without it ever tripping.

So no good asking here you need to ask your electrician and he has to make a risk assessment and decide what he can likely get away with.

 

[bowgieman]

Thanks for the replies.

Also if I were to get the 20amp mcb upgraded to 32amp and also have an additional 32amp mcb installed for the new circuit, I was wondering if the Fused Connection Unit can handle this. Does it have a maximum capacity?

I currently have the follwing MCBs

2 * 20 Amp
1 * 30 Amp
2 * 15 Amp
1 * 5 Amp
1 * 3 Amp

Total 108 Amp; its quite an old box with no RCD fuse.

 

[winston1]

Thanks for the replies.

Also if I were to get the 20amp mcb upgraded to 32amp and also have an additional 32amp mcb installed for the new circuit, I was wondering if the Fused Connection Unit can handle this. Does it have a maximum capacity?

I currently have the follwing MCBs

2 * 20 Amp
1 * 30 Amp
2 * 15 Amp
1 * 5 Amp
1 * 1 Amp

Total 97 Amp; its quite an old box with no RCD fuse.

I make the total 106 amps but it doesn't matter as you won't have everything running at full load at once.

You will need a RCD though for the new work.

 

[winston1]

2) Items over 2kW fixed should have a dedicated supply so oven (electric), hob (electric), washing machine, tumble drier, and dish washer should all have there own supply. Often only oven and hob have dedicated supply but this is down to the electrician doing the work.

[/quote

Where does this gem come from?

Never heard of a washing machine, tumble dryer, or dish washer needing their own supply. They come with fitted plugs ready to plug into the normal ring main. All 3 would unlikely to be run at the same time so no problem.

 

[DaftPunk]

Try reading the regs. It's all in there. I'll give you a clue with appendix 13.

 

[bowgieman]

Thanks guys, appreciate all your help.

Can i have some advice regrading the below please? thanks,

The current 20amp radial circuit (2.5 T&E cable )currently feeds the combi boiler, washing machine and the worktop sockets. Is this okay or does it need upgrading to a ring circuit with a 32amp mcb?

The new Built in Oven, Microwave and Fridge would be located away from the worktop area in a larder cabinet, so I could possibly have the three appliances on a new 32amp circuit? Would this be Ring or radial? Which would be better?

 

[PrenticeBoyofDerry]

The current 20amp radial circuit (2.5 T&E cable )currently feeds the combi boiler, washing machine and the worktop sockets. Is this okay or does it need upgrading to a ring circuit with a 32amp mcb?

The set up is not unsafe, and historically you have had no overload issues (have you?) If not not it seems fine.

The new Built in Oven, Microwave and Fridge would be located away from the worktop area in a larder cabinet, so I could possibly have the three appliances on a new 32amp circuit? Would this be Ring or radial? Which would be better?

It would be best to have the cooker on it's own radial circuit!
As for the other appliances, they are in the same location, so a radial will likely mean less cable is required and can be run in 2.5mm on a 20A device.

But as stated previously, do not overlook the requirement or RCD protection, I would seriously consider at this stage have the circuits designed for kitchen to make best use of the circuits and required loads.
Also a new consumer unit would be a major consideration as you are going to require extra ways for circuits and RCD protection, so would be a logical move and with more ways the kitchen can then have better designed circuits for appliances and to reduce complete power-loss within the kitchen.

 

[ekmdgrf]

Hi,

Is it okay to have all kitchen appliances on one ring main on a 20amp mcb? I am planning on having a new kitchen installed with the built in appliances listed below together with the wattage, which all adds up to 12500 Watts. I will be getting a sparky in to do the work but I wanted to get an idea of the work that needs to be done and what my options are. Do I need to have 2 circuits and also change the mcb to 30amp? And what would be the costs?

Many thanks in advance.

Cooke And Lewis Single Oven CLEF3SS-C 13amp (not sure of the Wattage. Is this 13*230 = 2990?)
Microwave – 800W Heating, 1000W Grill
Fridge – CATA BIF77A 800W
Washing Machine 750W
Kettle – 3000w
Toaster – 1800w
Combi Boiler, Potterton Titanium 33E – 3amp – 720W
Gas Hob Ignition – 3amp – 720W
Cooker Hood – 3amp – 720W

You can reduce the load by 4A by Freecycling the microwave. I did this a few years ago and haven't looked back.