Isolation and Switching in Domestic Kitchens…
Let’s take a look at a few definitions first…
Isolation: Function intended to make dead for reasons of safety all or a discrete section of the electrical installation by separating the electrical installation, or a section thereof, from every source of electrical energy.
Emergency Switching: An operation intended to remove, as quickly as possible, danger, which may have occurred unexpectedly.
Functional Switching: An operation intended to switch ‘on’ or ‘off’ or vary the supply of electrical energy to all or part of an installation for normal purposes.
Ordinary Person: Person who is neither a skilled or instructed person.(e.g. a person living in a house)
In normal circumstances all that would be required for an ordinary person is functional switching. They would have not have the need to isolate any part of the installation or equipment as they are not competent to complete any maintenance or installation work.
However, things can go wrong in the kitchen, such as a fire in the electric oven or on the hob and there may be a need to switch things off as quickly as possible and this can be achieved using emergency switching.
Also, where maintenance from a skilled person may be required during the lifetime of the kitchen such as washing machine repairs then a method of isolation may also be required.
* For guidance on switches and devices that can be used for isolation, emergency switching and functional switching have a look at Chapter 53, 537 Isolation and Switching and Table 537.4
Most common devices and their use…
Plug and switched socket outlet: Isolation – Yes, Emergency Switching – No, Functional Switching – Yes.
Switched fuse connection unit: Isolation – Yes, Emergency Switching – Yes, Functional Switching – Yes.
Cooker control unit switch: Isolation – Yes, Emergency Switching – Yes, Functional Switching – Yes.
A combination using a switched fuse connection unit above the worktop supplying a socket outlet at low level is most often used and provides isolation, emergency switching and functional switching. If just isolation and functional switching is required then a plug and switched socket outlet that is readily accessible can be used.
There is no guidance as far as positioning is concerned but devices provided for emergency switching should be readily accessible and identifiable and close to the equipment and in the case of cooking appliances not placed directly above.
All definitions and regulation references apply to BS7671:2018 ’18th Edition Wiring Regulations’