I was wondering if anyone has changed there pole cap top colour codes because of the 17th edition recommendation for core colours? On one of our recent installations our contractor has altered them as they claim 17th edition states that green and green yellow are earth, purple, grey and black( forgive me if I'm wrong) are reserved for 3 phase. Obviously this causes problems as it would make some cores not strictly usable, and the standard red, white, blue and Brown yellow green for phase colours, and purple for "regs" supply, have been altered by the contractor
My feelings are these regarding the 17th edition and cable colours are - yes when it is a constant supply. But as for the core for the phases, I would class them as a control (at either ELV or LV) and not strictly a supply so would not have to comply to the 17th edition on colour codes. As such I may look at getting the to alter the new site back to the original colour codes.
Hope it makes sense, any feeling on this

If you are responsible for the electrical design of the traffic signal installation, the contractor as no right to change any part of your design without consulting you first.
The single color green is not designated as a circuit protective conductor(earth continuity conductor).
The correct colour code for the circuit protective conductor is green & yellow.
In armoured cables it is permmitted to use the steel wire armouring as the circuit protective conductor,
To identify which functions are designated to the individual colour identification of the cores of the cable is given by the Top-Cap wiring schedule.
As the cable which is supplied by the manufacturer should be to BS 6346 and it as the single color green simply add further identification to it for e.g. marking tape, sleeving, or a number.
BS 7671 says single phase ac (Traffic Signal Installation) cabling is Brown -Live, Blue-neutral & green/yellow -circuit protective conductor. Therefore to comply with BS7671 are we saying that all the cores in the multicore armoured cable should be either Browm -Live and Blue-neutral.
In Traffic signals we are using the cable for signalling and hence the different colour code of the conductors for ease in the identification of the cores. Please note you can also purchase cable with all the conductors having white insulation each being individually identified by a number, again if you assign a number to a paticular function for eg 0-neutral, 1-red, 2-amber, 3 green etc, you identify what you use on your Top-Cap wiring shedule.
It is preferable to have the same colour code throughout the length of the cable, but in this case the cores can only have additional identification at terminations.
BS7671 Required Documentation. On the installation certificate there is a section for signatures of people responsible for the installation i.e. For Design, For Construction, For inspection and Testing
In the Design section there is a ssection for Details of Departures from BS 7671, just simply note the the colour coding of the cables.
Any departures from BS7671 are also recoreded by the Constructor and the Person responsible for Inspection and Testing.
It is to be hoped that if you are responsible for the electrical element of a signal installation or any other type of Highway installation that all are correctly designing, constructing, Inpecting & testing and certifing your Traffic Signal Installations work according to BS 7671.

Please note for the new elv dc the cabeling is Brown - Positive and Blue Negative?