Selection and Erection – Equipment
Control circuits, ELV and other applications It should be noted that in the last part of Table 51 ‘Control circuits, ELV and other applications’ the use of other cable colours is allowed for these particular applications. This can be for any application where the general standard power colours are not preferred. An example of where this would be used would be a lock-stop button control cable, where it is desired to use, say, violet as a colour. It should be noted that additional termination marking (by colour or characters) would not be necessary (the information relating to violet as a colour for the lockstop cable would normally be contained on schedules or schematic diagrams).
D 3.3
Identification by marking Colour identification does not have to be used, and of course sometimes cannot be used, for example when using MICC cables. In these cases, or where the designer or installer simply does not prefer colour, identification by marking at terminations is used. Section 514 of BS 7671: 2008 allows you the flexibility to select an identification system that works for you and the application. This may either be the alphanumeric identification of Table 51 or can be by numbering (514.5.4). Numbering may be the preferred method of identification; for example, multicore armoured termination kits. Take a 27-core armoured cable. The cores are numbered from 0 to 26; in the installation, a number of these may be used for neutrals and others used for earths (514.5.4 states that the number 0 should be used for the neutral). They are all coloured black. Normally, to satisfy other parts of BS 7671, a suitable wiring diagram or equivalent will be required, indicating the use of the numbers (unless there is no possibility of confusion).
D 3.4
Additions and alterations – identification Where pre-2004 harmonized cable colours (generally red, yellow, blue and black) and harmonized colours (generally brown, black, grey and blue) are used in the same installation, the following label must be applied at the relevant distribution boards or items of switchgear as appropriate. CAUTION: This installation has wiring colours to two versions of BS 7671. Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified. It should be noted that this label need not be applied at all other points on circuits, only at the point of the circuits most likely to be used for isolation in the future, most commonly the distribution boards or items of switchgear.
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D