Electricians among you - your advice please.

  jack 11:59 05 Aug 2009

A total bathroom refit has been carried out - so now I am finishing off.
New Class 3 light unit is going in
The instruction are quite explicit-
'It must be earthed'

The house lighting loop is two wire - no earth -as far as I can see -
So should I ignore this advice or endeavour to comply by making a new earth to a water pipe[say]?

  I am Spartacus 12:03 05 Aug 2009

I'm not an electrician but when we had one in last year he found that all our upstairs lighting was two wire with no earth whereas today it would all include an earth as well. He told us to avoid using metal light fittings.

I thought you had to use a qualified electrician even to fit a new light unit?

  woodchip 12:14 05 Aug 2009

You could run it to the Cold Pip if it continuous Copper Lead etc and Bonded into the Earth System

  lotvic 12:22 05 Aug 2009

I suggest you get an electrician especially as it is in the bathroom.
here are the regulations click here scroll down to 'Electrics'

""With effect from 1st January 2005, Part P (Electrical safety) of the Building Regulations came into force, these mean that only very limited work can be carried out by non-certified people without notification to the local Building Control authority.

Work which can be carried out by a non-certified individual without notification consists of:

* Replacement of fittings such as sockets, switches and light fittings.
* Replacement of the cable for a single circuit where it has been damaged.
* Work that is not in the bathroom or kitchen and consists of:
o Adding additional lighting, light fittings and switches, to an existing circuit.
o Adding additional sockets and fused spurs to an existing ring or radial main.
o Installing additional earth bonding.

All this is conditional upon the use of suitable cable and fittings for the application, that the circuit protective measures are unaffected and suitable for protecting the new circuit, and that all work complies with all other appropriate regulations.

All other work must either be carried out by certified individuals/companies or notified to the local Building Control before work begins, this includes:

* All new or modifications to the electrical wiring within bathrooms or shower rooms.
* Installation or modification of electric underfloor or ceiling heating.
* Garden lighting or power installation.
* Other specialist electrical installation, examples being, Photovoltaic Solar and micro CHP power systems.

If in doubt, check with the local Building Control.

These rules DO apply to DIY activities, anyone carrying out DIY changes which are notifiable will have to submit a building notice to the local authority before starting work and pay the fee to have the work inspected and tested.

Problems may be encountered when trying to sell a property which has had notifiable electrical work carried out but for which the appropriate certificate cannot be produced. ""

  birdface 12:30 05 Aug 2009

Check again some of the cable used to have a bare copper wire in them.

  anniesboy 12:54 05 Aug 2009

Speaking as an ex electrician (very ex).
I'm sure your existing lighting circuit will have an earth wire. Well certainly should have.
It might be a bare copper wire or a wire with a green or green/yellow sleeve.
Earth wires can sometimes be behind the existing fitting.
Attaching a wire to a copper pipe wont necessarily provide a good earth.
If in doubt get it checked by an electrician.

  crosstrainer 12:56 05 Aug 2009

Lotvic is correct...The lighting, (and any fans if fitted) MUST be earthed back to a modern Circuit breaker board.

If you are in any doubt, contact a Qualified sparks.

Water and electricity make a very bad combination.

  Tonsie 14:54 05 Aug 2009

Well Jack,if i was to earth your light fitting i
would run a 1.5mm earth cable to the nearest 13amp
socket.To be on the save side run the earth cable
back to the main consumer unit.

I am a retired JIB approved electrician.


  Fruit Bat /\0/\ 16:41 05 Aug 2009

If there is no earth to flow to, then the RCB will not trip.

My 1963 built house has no earthing to any of the lighting circuit fittings.

I have run new 2.5mm earths from all my Bathroom equipment (fan, light switch, lamp and shower switchback box) to a junction box in the ceiling and connected them back to the consumer unit earth rail.

  Fruit Bat /\0/\ 16:48 05 Aug 2009

looks as if I am going to have to change that under the latest regulations and earth to a local earth source

click here

back in ten minutes.....

  Longhouse 16:58 05 Aug 2009

I'm not a qualified electrician but could be classed as a "competent person" and have undertaken domestic & industrial electrical work for many years alongside qualified electrical engineers & electricians. (that's the disclaimer out of the way!)

My understanding of part P of the building regulations and the 17th edition of the IEE wiring regulations is that you are allowed to change light fittings. You are also allowed to upgrade the earthing circuit to current standards.

However, where a circuit in a location containing a bath or shower (or other "special location") is involved and is to be modified, you will likely require the services of a part P qualified person to either undertake the installation or check & certify the work.

If you still feel that you are competant (with regard to the regulations) you may need to consider the following:

- Is the existing wiring suitable for what you propose?
- Is the existing main protective bonding conductor to your services up to standard?
- can you connect the necessary supplementary earth bonding to a suitable point and are all exposed or extraneous conductive parts in the room connected to the same earth (all must be at the same earth potential)?
- is the circuit protective device capable of the required disconnection time and level of required protection?
- Is the light point (switch or fitting) within zones 0,1 or 2 (proximity to bath or shower)?

My own thoughts are that I would:

check that the main earth connection from the earth point on the distribution board to the water service pipework is at least 6mm (regulations now 10mm minimum) and continuous.

Install supplemental bonding of 4mm (see table 4.3 of the on site guide to BS7671:2008) to all pipework, metal fittings and electrical fittings in the room. You could use smaller xs if it's mechanically protected.

check that the final circuit is protected by a 30mA RCD or RCBO (but for the RCD or RCBO to work on the circuit, the circuit needs to eb earthed)

and finally, think about installing a low voltage light (SELV or PELV)

Hope that helps without confusing you

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

Alienware 17 R4 2017 review

These brilliant Lego posters show just what children's imaginations are capable of

Mac power user tips and hidden tricks

Comment réinitialiser votre PC, ordinateur portable ou tablette Windows ?