In this issue of the Electricity News , we have invited Mr LEUNG Chi-ming, Joseph, the chairman of the Electrical Safety Advisory Committee who serves for a second term to address our readers. Popular singer Stephy Tang shares with you some safety tips on choosing and using high definition television set-top boxes in a feature article. Another feature article covers the periodic inspection and testing items for electrical installations, for the reference of registered electrical contractors and workers.
The Electrical and Mechanical Services Department (the EMSD) and the trade have established a working group to review and revise the Code of Practice for the Electricity (Wiring) Regulations (2003 Edition). The progress of the review is reported in the "News". Moreover, an update on the adoption of new international safety standards for electrical products supplied in Hong Kong is given in the "News".
To mark the 60th anniversary of the establishment of the EMSD, a 60th anniversary launching ceremony was held in the EMSD Headquarters on 12 February. All former Directors of Electrical and Mechanical Services were invited to officiate at the ceremony. An exhibition entitled "EMSD 60 Years in Perspective" has been held at the main entrance lobby of the EMSD Headquarters from that day on for the guests, visitors and colleagues. Readers can share our joys by reading the "Snapshot".
LEUNG Chi-ming, Joseph
Chairman of the ESAC
I have been the chairman of the ESAC since April 2006. Looking back, during my two-years term of office, which was also the 4th term of the ESAC, members of the ESAC discussed a variety of issues relating to electrical safety in Hong Kong. The issues included the revision of the Code of Practice for the Electricity (Wiring) Regulations , the progress of the implementation of the new cable colour code, the adoption of the latest international safety standards for electrical products, cooperation with the mainland authorities, the review of incidents involving fixed electrical installations, electrical products and electricity supply lines, and the publicity work on electrical safety etc. The ESAC also made constructive suggestions to the EMSD. With the concerted efforts of the ESAC and the EMSD, the electrical safety records in Hong Kong have been improving in the past years. Public awareness of electrical safety has also been greatly enhanced. These results are encouraging.
ESAC meeting
In April this year, I am honoured to have been appointed again by the Secretary for the Environment as the chairman of the ESAC for a second term. I look forward to cooperating with the committee members in the new term. We will continue to work hard to enhance safety in the supply and use of electricity in this Asia's world city. Last but not least, I would like to extend my heartfelt thanks to my fellow committee members for their support and contributions over the past years.
The cover girl of this issue of Electricity News is Stephy Tang, a popular singer in Hong Kong. She was a member of the singing group Cookies, but has worked independently since 2005. Four personal albums have been released to date and she is quite popular among young music fans. Besides singing, Stephy starred in numerous films and television dramas and published her own works, so she is versatile. Wilson Chiu, an Electrical and Mechanical Engineer of the EMSD, acted as a reporter and had an exclusive interview with Stephy.
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"Hi! Stephy. You pursue a career in music, film and television and become very busy. How can you cope with it?" |
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"I have to thank my agents for taking the best care of me. Despite my tight work schedule, things went smoothly. In addition, other personnel were very professional and we cooperated well. So I have been able to cope with my busy work." |
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"What are your pastimes?" |
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"My favourite pastimes are watching films and television." |
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"Digital television was officially launched at the end of last year. The content of high definition television programmes is becoming richer. You can enjoy high quality audio-visual entertainment at home."? |
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"What is digital television? How does it differ from traditional television?" |
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"Digital television refers to broadcasting television images and sounds in digital format. Rather than being broadcast as continuous analogue signals, digital television signals are sent as discrete bits of information. Digital television can improve picture quality and eliminates reception problems such as 'ghosting' or 'snowing'. It is also capable of providing new features and service, such as high definition television (HDTV) programmes, interactive service, mobile reception, widescreen pictures, surround sound (e.g. Dolby Digital 5.1 channels), multiple viewing angles, multi-channelling, closed-captioning and electronic programme guides. It allows broadcasters to offer viewers a range of new and different service." |
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"There are TV sets of various resolutions in the market. What do they mean?" |
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"A picture on the TV screen is formed by a large number of small dots called pixels. The higher the number of pixels, the better the picture quality will be. The pictures of conventional analogue TV broadcasting provide a maximum of 720 (horizontal) ? 576 (vertical) pixels. Typically, the pictures of HDTV broadcasting provide a resolution of at least 1,024 horizontal pixels ? 720 vertical pixels and hence they have a better picture quality than those of analogue TV broadcasting. At present, the digital TV pictures in Hong Kong are displayed in a wide screen (aspect ratio 16:9) format, and the resolution may be either 720p (1,280 ? 720, progressive scanning) or 1080i (1,920 ? 1,080, interlaced scanning)." |
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"What equipment do I need to watch digital TV?" |
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"In order to watch digital TV, you have to modify your communal aerial broadcast distribution system or use a standalone aerial to receive digital TV signals. In addition, you need to add a set-top box to your existing TV set or buy a TV set with built-in digital TV reception capabilities. As set-top box and TV set with built-in digital TV capabilities are electrical products, they should meet the safety requirements stipulated by the Electrical Products (Safety) Regulation. Normally, set-top boxes or TV sets with built-in digital TV reception capabilities complying with the safety standard IEC 60065 are acceptable. If a set-top box uses an external transformer, the transformer should meet the safety standard IEC 60950." |
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 "So I have to buy a set-top box to watch HDTV programmes. Can you give me some tips?" |
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"Set-top boxes sold in Hong Kong should meet relevant international safety standards. You should buy set-top boxes with product information (e.g. brand, model and voltage) and 3-pin plugs complying with safety requirements. When using a set-top box, make sure that there is sufficient space for heat dissipation around it. If you detect abnormal sound or smell, stop using it and unplug it at once. If you do not use the set-top box for a long time, switch it off and you will be perfectly safe." |
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"Thank you for your professional advice. Now I know how to buy and use a high quality and safe set-top box." |
: Stephy Tang: Ir Wilson Chiu
Acknowledgement: Gold Label Entertainment Limited
According to the Electricity Ordinance , a fixed electrical installation means "a low or high voltage electrical installation that is fixed to premises but does not include any electrical equipment that is supplied with electricity after passing through a socket of the installation at which the supply can be disconnected without the use of a tool".
The communal electrical installations of a building to be inspected and tested periodically normally include the main switch, riser, secondary meters and switches of all floors, earthing arrangements, equipotential bonding etc. of the power supply system. For buildings, housing estates and clubs completed recently, communal fixed electrical installations may include main switchboards, emergency generators, lifts, fire service installations, pump installations, lightning protection installations and the supply system of security equipment.
Before the test, registered electrical contractors and workers should make proper preparations. In particular, discussions with owners of fixed electrical installations are vital. Work programmes should be drawn up and cover the following matters:
Precautionary measures should be taken by registered electrical workers responsible for the work during inspection and testing and the method of tests should be such that no danger to persons or property can occur even if the circuit being tested is defective. Moreover, the responsible registered electrical workers should conduct inspection and testing in person or monitor the inspection and testing on the spot to ensure electrical safety.
Registered electrical workers should firstly visually inspect all parts of the fixed electrical installations to ascertain if the electrical equipment is selected correctly, installed properly and free from obvious defects. Then they have to inspect the connection and identification of conductors, signs, warning notices, protective devices etc.
Regarding the inspection and testing items, registered electrical workers should carry out the following tests:
In the event of any inspection or test indicating failure to comply, that test and those preceding, the results of which may have been influenced by the fault indicated, should be repeated after the fault has been rectified to ensure safety.
After completion of the inspection and testing, the registered electrical workers should properly record the data obtained on the checklists and test record forms. There are different checklists for fixed electrical installations completed in different years. Please refer to the checklists numbered 1, 2, 3, 4 and 5 in Appendix 13 of the Code of Practice for the Electricity (Wiring) Regulations for checklist samples.
| Electrical work | Checklists to be used |
|---|---|
| (a) Periodic inspection and testing for a low voltage installation | |
| (i) Connected to supply before 1985 | 1 |
| (ii) Connected to supply in or after 1985 and before June 1992 | 1 and 2 |
| (iii) Connected to supply in or after June 1992 | 1 , 2 and 3 |
| (b) Addition and alteration of a low voltage installation | 1 , 2 , 3 and 4 |
| (c) High voltage installation | 5 |
After completion of the inspection and testing, the registered electrical contractors and workers should issue Periodic Test Certificates (WR2) within the statutory period and prepare the following documents:
For filling in the Periodic Test Certificate (WR2) correctly, please refer to the Electricity News (Issue 11).
Owners of electrical installations or their agents shall submit the test certificates, other relevant information and the endorsement fees to the EMSD for endorsement within 2 weeks after the date of the certificate.
In addition, registered electrical contractors should keep all records of electrical work for the last 5 years. They should also provide the EMSD with their records, drawings or documents for inspection upon request.
The EMSD published the first edition of the Code of Practice for the Electricity (Wiring) Regulations (hereinafter referred to as "CoP" ) in 1992 to provide the electrical trade with technical guidelines on how the requirements of the Electricity (Wiring) Regulations can be met. The EMSD reviews and revises the CoP regularly to ensure that its safety and technical requirements are up-to-date.
The EMSD has established a working group whose members came from academic institutes, engineering consultants, professional institutions, power companies, trade associations and other government departments to review the latest round of revisions to the 2003 Edition of the CoP . The working group has held several meetings so far to propose revisions according to the latest international standards (including British Standard BS 7671:2008 which is equivalent to the IEE Wiring Regulations 17th Edition) and the feedback from trade members. The proposed revisions, which include the increase of minimum insulation resistance, the update of installation requirement for electrical equipment in bathrooms, the addition of a new code on grid connection of renewable energy power systems, the inclusion of the latest lightning protection standard etc., are expected to be finalised by late 2008.
The implementation of the new cable colour code has been smooth since its introduction on 1 July last year. This Department inspected some electrical installations with new colour cables and found that they were satisfactory. Regarding training for the trade, over 85% of registered electrical workers have completed new cable colour code training by undergoing web-based self-assessment or attending other training courses.
In the Amendment No. 1:2007 to the Code of Practice for the Electricity (Wiring) Regulations , items for checking relating to the new cable colour code are added to Checklist 4, Appendix 13 of the Code of Practice . The Checklist may be downloaded at the EMSD's web site.
As agreed by the EMSD and the trade, suppliers will supply electrical products complying with the new International Electrotechnical Commission (IEC) Standards according to Table 1 below:
| Product type | Applicable new safety standard | Date of Implementation |
|---|---|---|
| Electric fan, including exhaust fan | IEC60335-2-80 : 2002 | With effect from 1 January 2008, electric fans supplied in Hong Kong should meet the new IEC Standard. |
| The other 66 types of electrical products, including washing machines, refrigerators, air conditioners, microwave ovens and electric hair dryers | IEC 60335 Standard series published in 2002 or 2003 | Suppliers should import those electrical products meeting the new IEC standards from December 2008 onwards. |
The EMSD and the trade have also reached an agreement on the stocks of imported electrical products meeting the old standards. After 30 November this year, suppliers may still supply the market with the stocks of the remaining 66 types of electrical products meeting the old standards upon registering those stocks with the EMSD between 1 September and 30 November this year. They must also submit the information as shown in the sample in Table 2 below:
| Supplier Information | ABC Electrical Product Manufacturing Company Limited |
|---|---|
| Product type | Electric hair dryer |
| Brand | Beauty |
| Model | 456-N |
| Estimate stock | 100 |
| Date of submission | 1 September 2008 |
Details of the new safety standards have been uploaded to the EMSD's web site for the reference of the trade.
As a Registered Electrical Contractor or Registered Electrical Worker, you have to comply with the Electricity Ordinance and its subsidiary regulations. For your easy reference, this Department posts the Notice for Registered Electrical Contractors and Workers, including the relevant duties, period of registration, renewal of registration, display or keeping of the registration certificate, and the requirements of inspection, testing and certification for electrical installations, etc. For details, please browse the EMSD's web site or call the Government Hotline 1823. Registered Electrical Contractors and Workers shall always understand and comply with these requirements, so as to ensure the electrical safety of the workers and the public.
This year is the 60th anniversary of the EMSD. To mark the occasion, we organised a series of activities, including the 60th Anniversary Launching Ceremony held at the EMSD Headquarters Building on 12 February. All former Directors of Electrical and Mechanical Services (DEMS) were invited to officiate at the ceremony. Mr. HO Kwong-wai, Director, said that since its establishment in 1948, the EMSD had faced numerous challenges and we owed our many achievements to the leadership of all former Directors and the hard work of committed staff. The Director also wished that the EMSD would have many, many more anniversaries to celebrate. The guests then performed the unveiling ceremony of the commemorative plaque of DEMS. An exhibition entitled "EMSD 60 Years in Perspective" has been held for guests, visitors and colleagues at the main entrance lobby of the EMSD Headquarters Building since that day.
The EMSD has organized an annual large-scale technical seminar for the trade in collaboration with the Hong Kong & Kowloon Electrical Engineering and Appliances Trade Workers Union and the Hong Kong Electrical Contractors' Association since 2001. This year's seminar was held at the Jockey Club Auditorium of the Hong Kong Polytechnic University on the evening of 17 December 2007. The response was overwhelming and more than 800 electrical workers participated in the seminar.
The theme of this seminar was "Comply with Safety Regulations. Collaborate for a Bright Future" which has two meanings. We hoped that the trade could make concerted efforts to enhance electrical safety in Hong Kong. We also hoped that through energy conservation, Hong Kong could achieve sustainable development and have a bright future. At the seminar, experienced engineers of the EMSD talked about points to note during the periodic inspection, testing and certification of electrical installations, common defects of electrical installations & review of electrical incidents, high efficiency lighting systems and new technical guidelines on grid connection of renewable energy power generation systems. The attendees were very enthusiastic and actively participated in the Q&A session.
The EMSD and the trade will continue to work closely and organise different events to further enhance the technical standards and safety awareness of the trade.
The Electricity Legislation Division (ELD) of the EMSD has been giving full support to promotional activities on electrical and mechanical safety organised by the trade. The Hong Kong Federation of Electrical and Mechanical Contractors and the Federation of Hong Kong Electrical and Mechanical Industries Trade Unions organised the "E&M Safety Walk 2007" at the Po Leung Kuk Jockey Club Tai Tong Holiday Camp, Yuen Long on 16 December 2007. Mr. PANG Yiu-hung, Acting Chief Engineer, led the EMSD team (comprising several dozens of colleagues of the ELD and their families) to participate in this meaningful activity. The organisers invited Mr. HO Kwong-wai, Director, to be the officiating guest. Mr. HO and other participants warmed up before the event started.
The weather was fine. The participants walked from the Holiday Camp to the Tai Lam Country Park and enjoyed the scenery of the countryside and the Yuen Long Plain. It was a relaxing trip which helped relieve stress at work. After the walk, the organisers held an occupational safety and health quiz to enhance participants' awareness of occupational safety and health.
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The voltage used to test an earth electrode should be ________. |
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The main switchboard of a building is connected to two supply transformers by two air circuit breakers whose rated currents are 2,500A. The busbars which these two air circuit breakers protect are connected by an air circuit breaker which is normally open. These three air circuit breakers are interlocked electromechanically, so that only two of them are closed at any time. The maintenance of this fixed electrical installation should be carried out by registered electrical workers of Grade ________. |
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If a switchboard is provided with a capacitor to increase the power factor, what special precaution must be taken to protect the electrical workers during the inspection and testing of the switchboard? |
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After the completion of a fixed electrical installation, which form should the registered electrical worker and contractor issue to the installation owner to prove that the installation is completed and is safe upon testing? |
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5. |
In a 3-phase 4-wire power supply system, there are non-linear loads which may cause the neutral conductor to be overloaded. The main reason is: |
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(Answers: 1B, 2C, 3A, 4A and 5B)
We look forward to receiving your valuable feedback about this newsletter so that we may continue to improve it. Please complete the feedback form below and return it to Electricity Legislation Division, EMSD by post, fax or e-mail on or before 30 May 2008 (please refer to the contact information at the bottom of this page). To show our appreciation, the first 500[1] respondents will receive a small gift by post.
Electricity Legislation Division, EMSD, 3 Kai Shing Street, Kowloon, Hong Kong
1823
2895 4929