From 1 July 2009, new colour coded cables have to be used in new fixed electrical installations in Hong Kong.

In the old cable colour code, the colours of blue and black are used to identify phase and neutral conductors respectively. In the new cable colour code, the colours of blue and black are used to identify neutral and phase conductors (i.e. just opposite to the existing colour scheme). Such change may cause confusion to electrical workers. The use of old and new cable colours in the same electrical installations may give rise to electrical accidents if electrical workers do not pay due attention to their wiring works. To avoid electrical accidents, you are reminded to ensure that all electrical workers employed are aware of the change and have attended appropriate training before working on the electrical installations.

Letter Code
Old Colour CodeNew Colour Code

Phase of single phase circuit
(or  yellow  or  white  or  blue )


Phase 1 of 3-phase circuit  Red   Brown  L1
Phase 2 of 3-phase circuit  Yellow  or  white   Black  L2
Phase 3 of 3-phase circuit  Blue   Grey  L3
Neutral  Black   Blue  N
Protective conductor  Green  and  yellow   Green  and  yellow  --

Phase and neutral in the old and new colour code

For existing electrical installations, the old colour coded cables do not need to be replaced as a result of the change. Also the change is for fixed electrical installations, and so it will not affect or have an impact on household electrical appliances or electrical equipment. New colour coded cables are used for addition, alteration or improvement to existing FEIs. The registered electrical contractors and workers should follow the guidelines published by this Department.

Technical Guideline

The details of colour for identification of conductors in fixed electrical installations are shown in Code of Practice for the Electricity (Wiring) Regulations (CoP). (e.g. Codes 13D(2), 17F, Appendix 18 etc.)

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