New Cable Colour Code

Technical Guidelines

Installation guidelines | Cable supply evaluation

Installation guidelines

Installation Guides - Extensions, Alterations or Repair to an Existing Installation

Warning Notice

Where cables in new colour code are installed in an existing installation with old colour coded cables, a yellow warning notice in both English and Chinese (see Figure 3) should be displayed at or close to the nearest upstream distribution board (e.g. main switchboard, sub-main distribution board or consumer unit) of the affected installation. The warning notice should be durable and securely fixed in position. Letters and characters should be legible. The characters "Caution" (both Chinese and English) should not be less than 10 mm in height. Other characters should not be less than 5 mm in height. The warning notice should have a minimum size of 100mm (width) x 75mm (height).

Single-phase installation

Extension, alteration or repair to an existing single-phase installation should be wired in the colour of brown (for phase conductor), blue (for neutral conductor), and green-and-yellow (for protective conductor) as specified in Table 1.

Existing cables adopting red for phase and black for neutral
If the existing single phase installation has adopted the red colour for phase conductor and black for neutral conductor (i.e. correctly identified), both the new and old colour coded cables are considered unambiguously marked. It is therefore not necessary to provide additional marking / label at the interface between new and old colour coded cables (see Figure 4).

Existing cables adopting either yellow or blue for phase and black for neutral
Proper durable and legible labels or coding (such as cable ties, sleeves, ferrules etc.) should be provided on the new cables near the cable termination interface (see Figures 5(a) to 5(d)). The above provision is to standardize the wiring work for incorrectly identified cables and to avoid any possibility of mistaking the old "blue" (phase) cable as the new "blue" (neutral) cable.

Three-phase installation

Extension, alteration or repair to an existing 3-phase installation should be wired in the new colour code of brown/ black/ grey/ blue/ (green-and-yellow) as specified in Table 1.

At the wiring interface, both the new and old phase and neutral conductors should be fitted with proper durable and legible identification marked in L1, L2, L3 and N (Figure 6).

For the interface between new and old colour coded cables at a busbar chamber for an existing three-phase installation, an acceptable means of identification is illustrated in Figure 7

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