I'm about to do some rewiring in my house and prepare everything before I bring in an electrician to install a new consumer unit (I still have an old style unit and fuses) and connect everything up.
I bought a Siemens Logo unit to add some simple automation to the house. I just need to lay down cables from the light points to the consumer unit. the cable are of course the new type with brown and blue colours, but all the circuits in the house are red and black.
Is it ok to mix both sets of colours or will I have to replace all the old red and black cables as well?