Wednesday 7th January 2009

Kitchen Wiring

Circuit Design

A few years ago all you needed in a kitchen was a couple of sockets for the toaster, kettle and fridge; you may also have had an electric oven.

However today there are a growing number of electrical items that are used in the kitchen, just have a think,

See what I mean and the list goes on.

So whereas once upon a time you only needed a single circuit to supply the needs of the kitchen, you now require several. When Major Electrical design the circuits for a modern kitchen we take into account how the kitchen is to be used, and if it is on the ground floor, will there be a need for exterior power or lighting.

Below is a list of circuits that you may expect to find in a kitchen that has been designed by Major Electrical.

  1. Cooker Power 32amp radial
  2. Kitchen Sockets 32amp radial with 30ma RCBO
  3. Exterior Sockets 16amp radial with 30ma RCBO
  4. Washing Machine 16amp radial
  5. Tumble Dryer 16amp radial
  6. Dish Washer 16amp radial
  7. Fridge/Freezer 16amp radial
  8. Boiler 10amp radial
  9. Lights Kitchen 10amp radial

You can see that the sockets that can be expected to be used to supply equipment outside are protected by 30ma RCBO's, whereas the sockets that will supply the other equipment do not have the additional protection of the 30ma RCBO, why is this?

It is of prime importance that any socket that may be expected to supply equipment outside, is protected by a 30ma RCD (RCBO) So why not put all of the kitchen circuits on one 30ma RCBO?

A RCD (RCBO) works by monitoring the current that is flowing in the phase live conductor and in the phase neutral conductor, both of these should balance out, as the current that flows in one, returns in the other. If any current then leaks to earth, be it as a result of a fault or as an acceptable leakage, the RCD will detect this and if of a sufficient amount, disconnect the supply. This is good news if you are out in the garden and cut through the lead on the mower, but not so good if it takes out the fridge / freezer, due to the combined leakage of the washing machine and tumble dryer that were left on when you went out.

I mention above "an acceptable leakage" let me explain this a bit more.

All electrical equipment have some leakage to earth, some such as IT equipment have this due to the fitter system they use to give a constant voltage to the equipment, whilst others such as equipment that has heating elements have a leakage to earth that is inherent with they design but are completely safe.

The problem comes when you have a number of items connected and working that each have a small amount of earth leakage, when this is added together it may be above the level that the RCD will operate at and then you get nuisance tripping. So to avoid this and to prevent one item of equipment that may become faulty affecting another, we break down the circuits as shown. We have found that this is by far the best way of dealing with the power in a modern kitchen.

Socket for equipment below the worktop

It uses to be common to see rows of double pole switches and switched fused connection unit above the worktop that were to control equipment that was beneath. The equipment would have a socket set in the wall behind it and impossible to get at.

The way that we prefer to provide power to equipment below a worktop is to site a socket outlet within an adjacent cupboard, and then have a hole cut in the side of the cupboard to allow the plug to pass through. This way you can get to the socket for maintenance, without having to lift out the equipment which at times can be all but impossible to do. It also means that the plug is not squashed by pipe work or vulnerable to damp from leaking pipes.

If you still prefer to have a means of switching the equipment from above the worktop, this is still possible either by the use of a DP switch and a 13amp socket, or using a switched fused connection unit and an un-fused plug.

Lighting

The importance of good lighting in a kitchen is often over look. Today a kitchen is not just a working area in which to product a meal, it is far more likely to be a meeting area, dinning area, chill out zone, and yes a place to eat a meal. Each of these areas require a different type of lighting, No longer will one twin fluorescent fitting be the answer to all. You need task lighting over the worktops, accent over the dining table, and a general light in the kitchen it's self.

If we can, we will design the lighting so as you can have control over a number of lighting points and are able to dim them as required.

Please call us at Major Electrical if you would like our help on the above number or use our contact link to send us an email.