Switch Function Color Code

Cable supply evaluation

Purpose

The purpose of this report is to evaluate the impact of cable colour change in the U.K. and other European countries on the safety compliance, supply and price of electric cables supplied in Hong Kong.

Background

Electric cables in Hong Kong are identified by a colour code originated from the U.K. However, for the purpose of standardizing technical requirements, the European countries including the U.K. have aligned their cable colours for fixed electrical installations and a set of new colours (i.e. brown/ black/ grey/ blue/ (green-yellow)) was selected. With the endorsement of the Electrical Safety Advisory Committee (ESAC), the "Working Group on the Review of Cable Colour Code in Hong Kong" (Working Group) was established since year 2003 among the electrical trade and the Electrical and Mechanical Services Department (EMSD) to study the impact brought about by this issue and to make recommendation on the future strategy regarding the cable colour code in Hong Kong. This paper is prepared by the Technical Support Task Group (TSTG) under the Working Group.

Source of Cable Supply

A survey on the source of supply of low-voltage (LV) and high-voltage (HV) electric cables [see Note 1] used in Hong Kong was conducted in year 2004. It was revealed that our cables are mainly imported from the Mainland China and overseas countries such as Japan, the U.K. and South Africa. According to the information provided by the Census and Statistics Department, the source of origin and percentage shares of the total cost of HV and LV cables used in Hong Kong in year 2003 are shown in Table 1 below.

Table 1 – Source of Cable Supply

[Note1: "high voltage" means voltage normally exceeding low voltage;
"low voltage" means voltage normally exceeding extra low voltage but normally not exceeding- (a) between conductors, 1000V root mean square alternating current or 1500V direct current; or (b) between a conductor and earth, 600V root mean square alternating current or 900V direct current;
"extra low voltage" means voltage normally not exceeding- (a) 50V root mean square alternating current; or (b) 120V direct current, between conductors or between a conductor and earth.]

Type of Cables Affected

The above Task Group envisaged that the cable colour change would mainly affect the supply of LV multi-core cables. High-voltage cables (the conductors of which are identified with numerals) will not be affected by the colour change. For LV single-core single-insulated cables such as wiring cables in conduits, manufacturers will normally keep certain quantities of these cables in 10 standard colours (i.e. the Munsell colour [see Note 2]) in stock. These 10 standard colours will include both the new and the old colours (i.e. the brown/ black/ grey and red/yellow/blue). These colours are also specified in the standard BS 6746C (Colour chart for insulation and sheath of electric cables).
[Note 2: These colors are used in the wire & cable industry to meet Electronic Industries Association (EIA) RS359 Munsell Color Standards. The 10 colours are Black, Blue, Brown, Green, Grey, Orange, Purple, Red, White and Yellow.]

Safety Compliance and Alignment with Other Standards

LV cables commonly used in Hong Kong can generally be divided into two categories, i.e. cables used in general installations and fire resistant cables used in essential service and fire service installations. There are a number of certification bodies certifying the safety compliance or quality of electric cables in the world. Two certification bodies, that are commonly adopted by the trade in Hong Kong, are the BRE Certification Limited and British Approvals Service for Cables (BASEC) [see Note3]. They have been consulted regarding product certification beyond April 2006 when our current cable colour code in British Standards will become obsolete and be replaced by new colours.

[Note 3: Loss Prevention Certification Board (LPCB) is under the BRE Certification Limited. LPCB is a recognized mark in products used in fire service installations. BASEC is a recognized mark on quality assurance of electric cables. Electric cables bearing the above product certification mark are recognized as having achieved the required quality.]

The standards of BS 6387, BS 6207 or BS EN60702 or equivalent are currently accepted by the Fire Services Department (FSD). Details are shown in the FSD Circular Letter No. 1/2003 entitled "Minimum Fire Resisting Cable Requirements for Fire Service Installation"(see FSD website: www.hkfsd.gov.hk). According to the reply from BRE Certification Limited, the approval and certification to BS 6387 do not include cable colour. Therefore, the change of cable colour will not affect the safety compliance of fire resistant cables on the aspect of fire safety.

On the certification of safety and quality assurance of cables for general use, BASEC has advised that they do not have any technical difficulty in certifying cables which comply with the new standard.

In addition to the safety compliance and quality assurance issues discussed above, we also need to look into whether our cable colours should fully align with those widely-used national and international standards. Our current cable colour code is originated from the U.K. Since the red/ yellow/ blue/ black/ (yellow-green) colour system in relevant British Standards will become obsolete in April 2006, our current colour code will no longer comply with the new British Standards nor the relevant international standards (e.g. IEC and EN). However, the new colour code (i.e. the brown/ black/ grey/ blue/ (green-yellow)) will fully comply with major reference standards including the IEC, EN and BS.

Cable Supply

According to the results of above survey, a substantial percentage of LV electric cables used in Hong Kong are imported from the western countries. Since the U.K. and the major European countries (members of European Committee for Electrotechnical Standardization (CENELEC)) have adopted the new cable colour code, the supply and manufacturing of cables in old colour code will inevitably be affected.

Although our current cable colour code is still being used by other countries such as Singapore and Malaysia, it is expected that as we get closer to April 2006 when the U.K. will require the new colour coded cables in a mandatory manner, some cable manufacturers will switch to manufacture cables in the new colour code and will avoid keeping stock the old colour coded cables not commonly demanded by the market by them. The market for new colour coded cables will substantially increase and manufacturers are likely to opt for producing new colour coded cables only. Therefore, if our cable colour code remains unchanged, contractors in Hong Kong will need to place special orders for certain types of old colour coded cables in the future. According to the trade practice, a minimum order quantity (MOQ) with a longer delivery time is required for manufacturing cables to special orders. It is expected that the effect of MOQ and longer delivery time will eventually affect the project cost and project time in the Hong Kong industry.

Cable Price

The cable industry adopts the mode of batch type volume production. The contractors in Hong Kong may lose flexibility in choosing cable manufacturers for ordering old colour coded cables due to shrinking of the old colour coded cable market. In the short term, different colour codes are still adopted in different countries. We anticipate that under the current market-driven environment, cable manufacturers will still supply old colour coded cables but at a higher price as compared to the new colour coded cables. In the mid to long-term, the situations will worsen in about 1 to 2 years after April 2006 (the date when the use of the new cable colour coded cable will be mandatory in the U.K.) when certain types of old colour coded cables in stocks have been exhausted.

Conclusion

The adoption of new cable colour code will not affect the safety compliance of electric cables. As our current cable colour code does not comply with the current IEC and EN standards, the adoption of the new cable colour code will therefore enable Hong Kong to align its cable colour code with those adopted by the major western countries. As a substantial percentage of electric cables used in Hong Kong are imported from the western countries in which the new cable colour code have been adopted, the use of the new cable colour code will ensure a stable supply of cable to Hong Kong, prevent possible price fluctuation, and avoid a longer delivery time. Such advantages will benefit the trade and industry and will eventually benefit the general public.