Leccy Question : lighting re-wire

danm

just found out that we do not have any earth's in our lighting circuit.

Supposedly quite common in older properties, but means that we have limited choice over fittings etc. (Can i just earth a metal fitting to screw in the back of the wall box?)

What would be involved in a re-wire (lighting only) ...how much would this cost/how long would it take. Bare floorboards in most rooms still so probably quite accessible.

Might go down this route for safetys sake (and so i can have some nice chrome dimmers)

baldelectrician

Get someone in to do a PIR (periodic inspection report).

You should use a competent person for the work, links below

In Scotland:
Individuals regitered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/SearchCo.asp?T=Construction&ID=2

In England and Wales:
http://www.competentperson.co.uk

This will let you know if only the lights need to be done.
You may need a new consumer unit, upgrade of bonding (earthing of pipes - Gas & Water)

It will all come clear in the report.

Melly31

I've got no earth wires in my lights circuit & i've got very nice chrome & brass lights & dimmer switches in every room?
I didn't realise you needed earth wires?
They all work fine, i fitted them myself over last couple of years & we've never had any probs?

Mel.

ianeverton

Melly31 wrote: »

I've got no earth wires in my lights circuit & i've got very nice chrome & brass lights & dimmer switches in every room?
I didn't realise you needed earth wires?
They all work fine, i fitted them myself over last couple of years & we've never had any probs?

Mel.

While your lights and dimmers will work this is a highly dangerous arrangement, especially the switches.

Under fault conditions where a live cable comes into contact with the metal of either your dimmers or light fitting normally it travels down the earthing which allows a large current to flow tripping or blowing your fuses or breakers.

In your situation this wont happen and the metal parts will remain live so when someone touches the switch/light they will get an electric shock.

Get it sorted immediately you are risking the lives of yourself and your family.

I am a JIB Approved Electrician of 15 years.

uncle_buck_3

On the subject of earthing …can any of the electricians explain why earth sleeving is fitted onto the earth wire of twin & earth cables….surely you want as much of the earth conductor exposed as possible!

ormus

if the live wire should break or come loose, then its better for it not to touch the bare earth, if poss, and short out.

uncle_buck_3

But surely that’s the whole point of the earth wire…so it does short out to earth!

ormus

the earth is surely to protect the person/s not the circuit?
better to have a non working socket rather than a blown fuse?
(and the whole circuit dead).

ianeverton

The sleeving is fitted to the earth to prevent it coming into contact with the live conductors inadvertently. If you think about it, when you fit the socket etc back onto its metal backbox the earth could kink over and touch the live.

The earth is to provide a very low resistance path for the current to flow, so that if, for instance the live wire comes out and touches the metal backbox a large current flows and blows the fuse quickly eliminating any risk of electrocution from live parts, like the fixing screws.

A fuse is to protect the circuit and wiring, it will never protect a person as the current required to blow a fuse (at least 5 amp) is more than enough to start your heart defibrillating and probably kill you.

And Ormus i know which i would choose, a full ring main dead and the chance to investigate why it has blown a fuse, or 1 non working socket that is potentially live with the chance of killing someone.