By Frank Bertie NAPIT Group Technical Director - Q: When we were replacing the accessories within the property we came across red and black conductors at the sockets and red, blue and yellow conductors at the switches. The earth conductors at all the accessories are bare copper without any sleeving. Do we have to install sleeving to all the conductors to the modern standards?
A: These cable colours were in use until 2006 when the “new” style brown and blue coloured cables.
Firstly if you are to retain part of the existing system, you are required to provide a label at the consumer unit stating that there are wiring colours to two versions of BS7671, as sample below.
It is permissible to leave the existing red and black conductors providing that they have been correctly identified.
The only requirement to provide new colour sleeving would be if there was some confusion to the identification of the conductors.
Regarding the bare earth conductors at the accessories, any items that you are working on should be provided with green and yellow sleeving. For any accessories that are not part of your work, you should inform your client of the current condition and recommend that an inspection of the existing installation is carried out.