Earth on metal light switches?

I live in a modern house that was built 7 years ago and we had a loft extension built a couple of years ago. We are in the process of re-decorating the loft and decided that chrome plated flat sockets and light switches would complement the modern look we were trying to achieve.

The fittings were ordered and received but I noticed that the light switches have earth connectors and a label saying "This metal plate must be earthed using the terminal marked earth".

On closer examination of my light switches, they don't appear to have earth cables, just a live and switched live wire! The ceiling roses do have earth connections but this earth isn't taken to the switches. I know from experience that this isn't unusual and is the way that the last three new houses I have lived in were wired.

Is it necessary for me to run an earth cable from the ceiling rose to the light switch in order to fit these new metal boxes?

Could you also help me with the definition of a lug. Another label on the switch says "If a 4 lug mounting box is used, the top & bottom lugs must be bent fully back". Is the lug the thing in the mounting bot that the screws screw into? I'm fairly sure it is but I'm not sure why you would ever get 4 in a mounting box. Because the light switches are fitted to plaster board walls in the loft, plastic mounting boxes have been used which have the adjustable fixings i.e. they pull tight onto the plaster board when the switch fitting is screwed on.

Thanks in advance for guidance on earthing the metal switches.

Reply to
Milleniumaire
Loading thread data ...

Ignore my question about the lug I have determined that my understanding is correct. I guess you might get 4 lugs in a metal mounting box that is meant to be used in solid walls, and as I recall these can be bent back flat so that they don't get in the way of the fitting.

Reply to
Milleniumaire

I'm not quite sure when lighting earths throughout the circuit became mandatory, but I'd say it was more than 7 years ago. My house has them and it was re-wired in '74...

And of course the one at the switch is perhaps the most important if using metal plate switches.

If this is easy, then simply change the cable to TW&E. Although you'll probably find it already is - but with the ECC cut off. Twin without earth really hasn't been readily available for many a year.

But if the house is 7 years old, still under warranty? Might be worth pursuing this.

Yes.

Some accessories have vertically aligned screws - although not so common these days.

They're called dry lining boxes, and I've not seen these with four lugs.

Reply to
Dave Plowman (News)

I didn't think you could buy house wiring cable without an earth wire 7 years ago. Before WWII possibly. If its grey coloured T&E the bare earth wire may be just cut back and not easily visible.

bland

Reply to
bland

In the 1960's I think.

My parents' house, wired in 1950's has earths in the switch drop wires, so they were fitted even before they were mandatory in some cases.

Yes, you mustn't use them without being earthed.

Reply to
Andrew Gabriel

Milleniumaire formulated on Sunday :

Something does not quite ring true with the above.

The provision of earths at both lighting points and switches became a requirement IMHO back in the late 60's/ early 70's. Green/yellow sleeving appeared sometime after that. If the place was built just 7 years ago, then certainly there should be earth points at the switches. If there aren't, then you should be chasing the builder to chase the original installer.

They should not be installed until you have the earths sorted out.

Then they must have been wired a very long time ago and would be well over due for rewireing.

Obsolutely, though you may well find that the earths have been cut off at the point the cable enters the switch. This was a common practise when the earth was first introduced and not needed.

Reply to
Harry Bloomfield

on 27/11/2005, bland supposed :

I think singles grey sheathed no earth, was available until quite recently and perhaps still is (?).

Reply to
Harry Bloomfield

Wow! Any exposed metalwork or metal-clad boxes (and linkage to their removable metal panels fitted with: mains switches, sockets, spur outlets, etc) must be bonded all the way to a good supply Earth. It's Common sense, it's the electricity regulations, and it's the law. This neglect could possibly nullify insurance claims, too. You could unbodge it safely by just running green PVC-covered braided 1.5sq mm copper wire from your reliable earth busbar (or from your ceiling rose if it is truly earthed) -hidden hopefully- to the exposed metal lighting-switch boxes and panels, and anything similar that is not yet earthed, or, to do it properly, you would have to rewire any such item with correct gauges of twin and earth (may have either the old or the new colours) and you will need 15A braided and green & yellow sleeving for the box-to-panel linkages. Before rewiring.... Make sure you have a good torch or secondary lighting, and kill the area mains supply!! Jim

Reply to
Jim Gregory

I've seen this done where there was a metal box with earth terminal. Must have saved a minute per switch.

Reply to
Dave Plowman (News)

Are the cables run through metal conduit which provides an earth? That is how the earthing for most of the sockets and switches in my flat is done - there is no seperate cable for those fittings.

Alex

Reply to
Alex

The UK Electricity Regs were updated by the newer edition over15 years ago from allowing just (proven unreliable) conduit continuity for earthing to stipulating a third wire to radiate from true earth in the consumer unit (or mains supply entry) to any outlet or power device, be it daisy-chained along a ring-main or at the end of a spur. As far as I know, only pendant incandescent lampholders, ES or Bayonet, made from thermoplastic are exempt from the 3rd installation wire. Steel via Conduit and sunken /surface boxes is used for its physical and sometimes EMI protection.

Alex, I would seriously ask you and/or the owners of the whole block of flats to have system earth-loop resistance testing and any necessary corrective safety measures done. If it cares at all about the risks of preventable accidental death, what does your buildings insurer say? Jim

Reply to
Jim Gregory

Eh?

What the hell are you talking about

Reply to
Alan Holmes

Ground wires, obviously.

Ground... Earth.... same tihng.

-- Beav OMF#19 VN 750 Zed Thou

mail is beavis dot original at ntlworld dot com (with the obvious changes)

Reply to
Beav

Which still doesn't excuse the fact that this is an off topic posting in rec.motorcycles. Please don't let it happen again.

thanks

Reply to
Rob Kleinschmidt

Why are you posting this in demon.local?

Reply to
ah

On Thu, 01 Dec 2005 05:32:46 GMT, via , ah spake thusly:

Because it's off-topic. I would have thought that that was obvious.

Reply to
Big Mouth Billy Bass

You'll not be warned again.

Reply to
ah

What's going to happen? Are yu going to seek him out and slap his legs? I demand jpegs at least, but a vid would be better.

-- Beav OMF#19 VN 750 Zed Thou

mail is beavis dot original at ntlworld dot com (with the obvious changes)

Reply to
Beav

formatting link
't underestimate our willingness to enforce The Rule.

Reply to
ah

I think you need educating as well

Reply to
Alan Holmes

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.