kitchen rewire questions

[VickyBH]

Hi all

I'm having renovation, my kitchen will be used for catering cooking and many appliances will to be used at the same time. I'm after some assurance that the the below circuit is fine and I won't get any tripping of circuit breaker in the middle of cooking?

- one 6mm cable in own radial circuit for 2 ovens, both loads are 3600W each.
- one 6mm cable in own radial circuit for an induction oven ( 7400W load).
- one 2.5mm cable in own radial circuit for 1 fridge freezer (186W) and an extra freezer (90W).
- 2.5mm cable in ring circuit for all other kitchen sockets (including dishwasher, boiler, kettle, air fryer, toaster, microwave, juicer, thermomix, blender, rice cooker...etc).

Distance from consumer unit to appliance is between 15 to 18 meters including drops.

My 2nd concern is that HOB/OVENS/FF/Freezer cables are not chased in nor clipped on wall. He said he will run the cable from bottom of kitchen unit but if this is possible for in a tall unit that's going to have Freezer, Oven & Oven (bottom to top.) Fridge Fridge is freestanding next to the tall unit, should it at least have own socket on the wall behind?

3rd question is my electrician insisted they connect all the hard wire appliance but kitchen installer prefer to do the connection too saying I'll get a better installation that way. Who's right?

Thanks in advance.

 

[donrkebab]

I assume catering means commercial, in my experience that means you need better than a standard installation. The main reason is that professional cooks tend to enter the kitchen and turn everything ON, that creates unusual electrical load. In view of this you need to determine the size of your main cut-out fuse, the standard is 60A which will probably be ok, but I would prefer 100A which will definitely be ok.

You need to avoid main RCDs, because they could result in complete power failure.

You don't mention sizes of circuit protection, MCBs RCBOs or fuses

The ring circuit should not have any permanent loads above 2kw

All appliances that come fitted with 13A plugs should connect to a socket outlet.

Regarding connecting, I would prefer the electrician to do it, kitchen installers and retailers are amateur electricians.

 

[JohnD]

ovens

When you say "ovens" do you mean ovens, or do you mean cookers?

 

[VickyBH]

When you say "ovens" do you mean ovens, or do you mean cookers?

Yes I meant 2 individual ovens, one steam oven and one microwave oven, both have connection rating 3600w according to manual.

I assume catering means commercial, ... ... you need to determine the size of your main cut-out fuse, the standard is 60A which will probably be ok, but I would prefer 100A which will definitely be ok.

You need to avoid main RCDs, because they could result in complete power failure.

You don't mention sizes of circuit protection, MCBs RCBOs or fuses

The ring circuit should not have any permanent loads above 2kw

All appliances that come fitted with 13A plugs should connect to a socket outlet.

Regarding connecting, I would prefer the electrician to do it, kitchen installers and retailers are amateur electricians.

It's not a commercial kitchen but also our home kitchen. I have another job and is doing 2-4 event per month, I am getting more enquiries now so I'll be cooking more in future. The mains fuse will be upgraded to 100A after new consumer unit is installed and the cable is upgraded.

I don't know about sizes of circuit protection because my electrician didn't tell me. I only listed down the cable he's laid down for each radial and ring circuit.

Does Boiler, Dish washer, microwave and cooker hood count as permeant load items? if so, then it's over 2KW already.

 

[JohnD]

Yes I meant 2 individual ovens

So you will have hobs as well. Are these gas? If electric, they are likely to have higher ratings than the ovens.

Does Boiler, Dish washer, microwave and cooker hood count as permeant load items? if so, then it's over 2KW already.

The boiler (what is this?) and dishwasher are likely to take about 3kW each during the heating cycle. So will the kettle, toaster and frier, though some of these may only be on for short periods.

Washing machines, tumbledriers and dishwashers all take high currents. The worst is the tumble drier because it takes a high current for a long time. Domestic dishwashers and washing machines take max load durig the heating cycle, in bursts of about 10-15 minutes. A commercial dishwasher may be heating throughout the period it is in use.

The cooker hood, lighting, mixer, fridge and freezer take negligible currents in terms of kitchen circuit design. it's the appliances that have heating elements that are heavy users.

In a kitchen that will be used for commercial purposes, you might do better with a radial circuit down each side of the kitchen, feeding sockets and appliances, with the usage divided between the two. This is also useful if you should have a circuit out of order, because you can move your small appliances to the side that still works.

Plug and socket are preferable to hard wiring for appliances of 3kW or less, because it is so easy to unplug them and put in a replacement when they go wrong. Freestanding appliances are preferable to built-in ones for the same reason.

 

[VickyBH]

So you will have hobs as well. Are these gas? If electric, they are likely to have higher ratings than the ovens.

Induction Hob with connection rating 7.4KW. I believe electrician will put it on it's own circuit because he only laid one cable from CU to Hob location.

The boiler (what is this?) and dishwasher are likely to take about 3kW each during the heating cycle. So will the kettle, toaster and frier, though some of these may only be on for short periods.

It's a gas boiler. I don't know about it's connection rating but I want it to share the same double socket with Dishwasher because they are in the same corner. Is that a bad idea? I see many flat/house have a fused switch for gas boiler but I don't see extra box/hole being chased. Do I need to get electrician to do one?

Thank for other detail comment, you have explained it well it's easy to understand. Washing machine and tumble dryer will be in a utility cupboard using a separate circuit. I will certainly ask my electrician about having two circuit on each side of kitchen, I think it's a great idea.

 

[JohnD]

A gas boiler uses negligible electricity.

Some gasmen will tell you that a boiler should be fitted to an isolating switch have a minimum 3mm separation of contacts. However, if you pull the plug out of the socket, it greatly exceeds that requirement.

The hob will need its own dedicated circuit. A 32A circuit is common and will be suitable for any hob or cooker I have ever seen in a house.