Lighting Circuits - Switches

This alternate connection method uses the same cables as the previous example, however the switch connections are different.

Alternate Connection Two way switching

Alternative two way switch connections, new colours

In this variation, the incoming permanenent line is connected directly to one wire of the three core cable. This core is connected to Common on the second switch. The return switched line is connected to the Common on the first switch.

This is the same wiring arrangement as would typically be used in a conduit installation, with the supply at one end and the outgoing switched line at the other.

The advantage of this arrangement is that each terminal only contains a single wire - this may be helpful if the switches have very small terminals, or the wires used are large.

However it does require the extra separate terminal block, which must be small enough to fit into the backbox with the switch.

Metal or Plastic

The diagrams show plastic switches, with the earth connection to the backbox or patress. Where metal switches are used, the earth should connect directly to the metal switch plate, with a short loop from there to the backbox.

Old colour codes

Alternative two way switch connections, old colours The same arrangement using pre-2005 colour coding, as typically found in older properties.

Although red is used as the common here, either the blue or yellow could be used - all of the wires are live, the only requirement being that the same colour coding is used at both switches.