Electrical Helper
Electrical Helper
Home Ask An Electrician Electricians
Electrical Help Contact Us
More Information
The Changes in Electrical Regulations
DIY Books
Cheap Tools



















Please read the disclaimer before attempting any electrical work. If you are uncertain then contact a qualified electrician.

What you are allowed to do yourself

  • You may change or repair a socket, light or cabling in any room.
  • You can add additional spurs, lights or sockets to an existing circuit unless it’s located in the kitchen, bathroom or outside.
  • You can install or replace an electric shower, garage door, cooker or gates as long as it’s on an existing circuit.
  • You may fit security lighting or air conditioning to outside lighting to the outdoor wall (unless a new circuit is required).
  • You may install outdoor sockets if it’s a pre-assembled kit only.

You must notify local building control for an electrical inspection and test when:

  • Adding a new circuit to an existing installation
  • Any electrical work is carried out in a room where water is present unless it’s a repair or replacement.
  • Any outdoor work e.g. garden sockets or lighting unless it’s a repair/replacement.
  • Replacement of consumer unit (fuse board/distribution unit)
  • Installation of central heating control wires.
  • Installation of a socket outlet that’s outside.
  • If a fully qualified electrician carries out any of the work above then you do not need to contact local authorities.
  • You should never carry out any electrical work unless you are 100% sure that the regulations you know are correct.

If you are unsure contact your local building control department for more information.

Electricity runs throughout your house through the walls, underneath the floor and in the ceiling to your appliances.

Information about cable

Cables that are used in domestic appliances usually have an oval cross section and have conductors inside called cores. In newer cabling the live or phase core is insulated with a brown sheath. The earth core is bare and runs between them. This is usually known as 2 core and earth cable. Special 3 core and earth cable is used in a 2 way light switch which has grey, brown and black cores. Any or all of these cores may be live. If the sheath is stripped from one of the core cables then you must put green/yellow earth cable over the earth core.

What has been changed?

The Institution of Engineering and Technology has made a change to its wiring regulations that tell the new cable core colours for any new fixed wiring in the electrical installations in the UK.
The new cable core colours are referred to as “harmonised” colours, and bring the UK more closer to the European colours.
Any electrical installations made after the 31st march 2006 must use the new colours.


Flex is short for flexible cord and is commonly used to connect pendant lights and appliances to fixed wiring. It will usually have 2 or 3 cores within the white or coloured PVC sheathing.
All cores are coloured:


Altering existing installations

When it comes to altering existing installations it may involve using a mixture of old and new colours.

Two core and earth cables

When you connect old and new cables at a socket or junction-box terminal you must make sure you connect the correct colours.

You must also fix the following warning notice at the consumer unit or distribution unit.


Working safely with electricity

Before you carry out any electrical work you should take the following precautions:

  • Turn off the main power at the consumer unit (fuse board/fuse box/distribution unit).
  • Isolate the circuit you are going to work on by taking the circuit fuse out or switching of the circuit breaker and locking it off. Tape the off button down with a note saying you’re working on a circuit.
  • Check the circuit isn’t live before working on it with a plug in socket tester or a voltage tester for lighting circuits.

Once you have completed the work replace the fuse/circuit breaker and then turn the power back on. You should never restore the power unit all the face plates and covers are fitted back on.

Three core and earth cables

The connections that are made in a two-way and intermediate light switch are such that the circuit can be broken or made at any switch point. The brown, grey and black cores may all be live at a light switch sometimes. They need to carry a warning of brown PVC sleeve or tape.

Old to new connections

You must also fix the following warning notice at the consumer unit or distribution unit.

Bookmark and Share



| All Information Is Copyright | Disclaimer | Electrical Helper 2010 |