Installing plug sockets in steel furniture.

[LParThree]

Hi all,

Figured I'd come straight to the experts with this one because I don't have a great deal of electrical experience.

I'm a designer at a furniture manufacturing company. We manufacture furniture almost entirely out of folded sheet steel profiles.

Currently I am working on designing a bespoke kitchen for a client, this client would like UK mains sockets installed on a couple of her units.

I'd just like to know if there are any regulations or best practice rules when it comes to installing electrical systems on a metal surface.

As far as I understand I'd need to ensure that the steel units are earth bounded to the structure of the building, is there anything else that I need to be aware of?

I want to make it as painless a job as possible for the electrician doing the install. Any advise would be much appreciated. Thanks in advance!

L

 

[James]

yes he is, I was responding to the previous post I think!

 

[loz2754]

I'm not averse to it. I guess I'm playing devil's advocate. An item of furniture is not in itself electrical equipment no matter if it's made of metal. The electrical equipment is the socket, which is to be attached to the furniture. Any cables supplying the socket would be insulated and sheathed. If you fixed a socket to a cable tray, would you then have to earth the cable tray?
Or if a socket was to be affixed to a stainless steel splashback, would you have to earth the splashback? A metal suspended ceiling light fitting is in direct contact with a metal ceiling grid, would you have to earth the grid?

And as an aside, the term "bonded" was used earlier, which is not the correct term for this sort of situation.

Like I said, I'm not averse to the furniture being earthed, but I also think that it's not an automatic assumption that it has to be, based on the definitions found in BS7671. When referring to equipment that could become live under fault conditions, the definition of such equipment does not include furniture. Unless of course the manufacturer of said furniture has designed it in such a way that it is part of the electrical equipment, and explicitly provides an earthing point to facilitate the connection to earth.

 

[loz2754]

Would you say the same for a washing machine or a tumble dryer ?

No I would not, because a washing machine and dryer are items of electrical equipment.

 

[loz2754]

Just a note to add:

If the furniture manufacturer designs electrical items into their products, do they then, in effect, become electrical equipment manufacturers, with all the legal requirements that that would entail, such as declaration of conformity to product standards etc?

 

[mainline]

My washing machine and tumble drier are bonded to earth via the cpc in the supply cable.
being an appliance they are subject to different standards but the fundamental principals are the same.

if a metal object can become live during a fault, then it should have a return path so the protective device can operate.

I don't understand why you seem to have such an aversion to earthing / bonding / attaching to cpc the body of a metal object that has cables running through it.

If you read my post properly you would see that I don’t have an aversion to earthing in fact it’s the opposite

 

[Avo Mk8]

Just a note to add:

If the furniture manufacturer designs electrical items into their products, do they then, in effect, become electrical equipment manufacturers, with all the legal requirements that that would entail, such as declaration of conformity to product standards etc?

That's probably true if your furniture product comes within the scope of IEC60364-7-713!
The iet seem to think furniture wired into a fixed installation would come under BS7671
This from an iet leaflet a long time ago!

 

[mainline]

That's probably true if your furniture product comes within the scope of IEC60364-7-713!
The iet seem to think furniture wired into a fixed installation would come under BS7671
This from an iet leaflet a long time ago!

I’m sure there was a debate I read a while back on earthing hospital type beds.