Kitchen wiring

[Jackthebiscuit]

Hello Guys,

I've been oversees for a while and just catching up on the new regs and recently looked at a friends kitchen which was installed about 2-years ago.

He only has socket outlets above the workbench and all socket for appliances are under the bench in the cupboards with no immediate means of isolation. Even the socket for the oven (and gas Hob with power cord) is under the bench in a cupboard. Given that a plug and socket are not deemed as a form of isolation in an emergency can I assume that (at least) the oven part of the install is against the regs? Is it no longer the practise to install a switch spur above the bench to control sockets below/above (cooker hood) the bench?

Also, to get the appliance cords into the cupboards he has cut off the manufactures plug-tops,,, pass the cord(s) thru a small hole drilled in the back of the unit,,, and then fitted his own plug-tops. Is this normal?

And finally, I read somewhere that if there is at least one fixed lug on a flush metal back-box that we no longer have to earth the back of the box,, can someone confirm that this is the case?

Thanks in advance

 

[ban-all-sheds]

Given that a plug and socket are not deemed as a form of isolation in an emergency can I assume that (at least) the oven part of the install is against the regs?

You can, but you'll find people arguing against that, often in the basis that there's always the MCB, which, to be fair, is deemed acceptable as the emergency switch for socket circuits, lighting circuits etc.

Is it no longer the practise to install a switch spur above the bench to control sockets below/above (cooker hood) the bench?

Don't know if it's ever been common practice, but it is done, as are FCUs supplying flex outlets or BS 543 sockets, or grids with switch and fuse modules supplying ditto, or plate switches supplying BS 1363 sockets. If you want you can find reasons why grid switches can't be used.

Also, to get the appliance cords into the cupboards he has cut off the manufactures plug-tops,,, pass the cord(s) thru a small hole drilled in the back of the unit,,, and then fitted his own plug-tops. Is this normal?

Yup.

Some people claim it will invalidate the appliance warranty, but I doubt that any attempt by a manufacturer to wriggle out of a warranty claim on that basis would stand up if the new plug had been competently fitted. Some makers say you can do it anyway, with the if-in-doubt-consult-a-qualified-electrician clause. (BTW - you're going to love finding out what counts as one of those these days.)

And finally, I read somewhere that if there is at least one fixed lug on a flush metal back-box that we no longer have to earth the back of the box,, can someone confirm that this is the case?

Blimey - you have been gone for quite a long while - what did you do?

There is no requirement to explicitly earth the box, but most people regard it as good practice to do so.

 

[flameport]

Also, to get the appliance cords into the cupboards he has cut off the manufactures plug-tops,,, pass the cord(s) thru a small hole drilled in the back of the unit,,, and then fitted his own plug-tops. Is this normal?

Often done, however a better way is to cut a larger round hole with a holesaw, so the plug can pass through without being removed.

 

[Jackthebiscuit]

I see the regs are as blurred as ever... or are they?

537.4.1.1/2. An emergency switch is to be provided for every part of an installation which may have to be disconnected rapidly from the supply to prevent or remove danger etc etc. (goes on about DP/SP switching etc)

537.4.2.8 A plug and socket-outlet or similar device must not be selected as a device for emergency switching.

Isolation.

5.1.1 iv. For every motor.

Every fixed electric motor should be provided with a readily accessible and easily operated device to switch off the motor and all associated equipment including any automatic circuit-breaker. The device must be so placed as to prevent danger.

I would have thought the over/stove/hob would come under an appliance that may need to be switched off rapidly. And in the case of a fan-forced oven even more so.

The cooker hood would also come under this. In my friends case I can only assume that the plug and socket are behind the stainless steel 'flue' and given it is a motor would need a more accessible means of isolation via an isolating switch and not a plug and socket.

Integrated washing machines/tumble dryers? Are they classed as 'fixed'?

Cutting the moulded plugs off new appliances.

In Oz/NZ this is not permitted so as flameport alluded to, electricians there drill a larger hole so the entire plug-top can pass thru the unit. The reason given was that the appliance must be able to be removed without the need for anyone to meddle with any electrical parts. Same applies with guarantees if the appliance needs to be removed. To me it seems senseless to purchase plug tops, and to then remove even better factory moulded plug-tops to install your own,, and one assumes, charge the customer accordingly.
.

Earthing the back of metal flush boxes.

When I was training we were told it had to be done because when the socket/switch/unit is unscrewed from the wall and being handled while live, that if there is no link that the metal box is no longer earthed. So the link provides earth continuity at all times.

If there is no longer a need to install a link if there is at least one fixed lug,, then i wonder why the manufacturers continue to install the earth terminal in the box at all..? Seems a waste to continue to manufacture a part that is no longer needed?

Thanks for the replies btw.

 

[ban-all-sheds]

537.4.1.1/2. An emergency switch is to be provided for every part of an installation which may have to be disconnected rapidly from the supply to prevent or remove danger etc etc. (goes on about DP/SP switching etc)

The circuit breaker.

5.1.1 iv. For every motor.

I don't think that is relevant to the sorts of appliances you get in normal domestic kitchens.

Integrated washing machines/tumble dryers? Are they classed as 'fixed'?

I would say yes, they meet the definition of a fixed appliance in Part 2.

To me it seems senseless to purchase plug tops, and to then remove even better factory moulded plug-tops to install your own,,

They aren't better, and they are very rarely as good and are often complete sh*te inside.

Manufacturers started fitting them not because they were better but because they were cheaper than proper plugs when legislation stopped them from supplying appliances with no plugs at all.

When I was training we were told it had to be done because when the socket/switch/unit is unscrewed from the wall and being handled while live, that if there is no link that the metal box is no longer earthed. So the link provides earth continuity at all times.

Where/when did you train, if you were taught that live working was OK?

If there is no longer a need to install a link if there is at least one fixed lug,, then i wonder why the manufacturers continue to install the earth terminal in the box at all..? Seems a waste to continue to manufacture a part that is no longer needed?

See above - maybe there are enough people who think it good practice to put products which don't provide an earth terminal at a disadvantage?

And if you're using them in a conduit system you may need a flylead to provide the connection to the socket earth terminal?

Or if you're using conduit as earthed mechanical protection as per 522.6.6(ii) you may need the flylead to ensure a good enough connection to carry a fault current?