From the Editor

We would like to thank you readers for your unfailing support and encouragement. Showbiz idol Fiona graces the cover of this issue of Electricity News. She will review and analyse with us the electrical incidents that have happened so trade practitioners can know more about the cause of these incidents. We hope that lessons can be learnt to prevent the incidents from happening again.

This issue also features "Safety Tips on Electric Water Heaters", "Continuing Professional Development Scheme for Registered Electrical Workers Entering into Second Training Cycle", "Proper Installation of Residual Current Operated Circuit-breaker with Integral Over-current Protection" and "Safety Tips on Electrical Appliances" to enable better understanding by members of the public.

Lastly, registered electrical workers are kindly reminded to complete and return the survey questionnaire. The information collected will be used for data enumeration and analysis. We would like to thank you for your cooperation.

Feature Article 1 - Safety Tips on Electric Water Heaters

The electric water heater is a commonly used household electrical appliance. Major types of electric water heaters available in the market include instantaneous, shower type (also known as low-pressure storage type or open type) and unvented thermal storage type (also known as high-pressure storage type). A typical shower type electric water heater is equipped with cold and hot water pipes, a mixing faucet, a shower head and thermostat-controlled heating element, as well as a thermal cutout. Although this type of electric water heater comes with appropriate safety devices, there have been occasional incidents involving these electric water heaters in the past. Investigation reveals that these incidents were mainly caused by improper installation and lack of maintenance.

Shower type electric water heaters in general are designed for showers, but in some cases the hot water is diverted to wash basins, and accidents occur because of the on/off control valves. The mixing faucet of the shower type electric water heater is not a normal valve. When the electric water heater is in standby mode (i.e., when the red and blue knobs are turned off as shown in the figure above) and the water inside the storage tank is being heated, the water will undergo slight thermal expansion. The pressure created inside the storage tank is released through the shower head. However, if a normal control valve is added at the outlet of the electric water heater, the pressure built up inside the storage tank cannot be released. Should the thermal cutout fail to disconnect the power supply, the storage tank may not be able to withstand the increasing pressure and this may result in a burst. Moreover, the outlet pipe of a shower type electric water heater must not be connected to a wash basin or bath tub. Otherwise, the outlet pipe will be blocked, leading to excessive pressure building up inside the electric water heater and causing an accident.

When it comes to the installation of electric water heaters, the associated water pipes and the fixed electrical installation of the electric water heater should be installed by a licensed plumber and a registered electrical worker (REW) respectively. When installing the fixed electrical installation of the electric water heater, the REW, apart from effectively earthing the electric water heater, should also check whether the electric water heater (including the thermostat) operates properly. When carrying out maintenance work on an electric water heater, the REW should follow the manufacturer's instructions. He should in particular check whether the fixed electrical installation and pipes are properly installed and whether the thermostat operates normally. If necessary, he should also consult the agent or manufacturer concerned. In case the REW finds that the outlet pipe is not properly installed, he should advise the user to appoint a licensed plumber to fix the problem immediately so as to prevent accidents.

Feature Article 2 - Continuing Professional Development Scheme for Registered Electrical Workers Entering into Second Training Cycle

Under the Continuing Professional Development (CPD) Scheme for Registered Electrical Workers (REWs), which was put into operation on 1 January 2012, all REWs are required to have completed two training modules, i.e., "Legislative and Safety Requirements" and "Technical Knowledge" when they apply for registration renewal. REWs may choose to complete their CPD training by attending seminars organised by the Electrical and Mechanical Services Department (EMSD), or training courses organised by recognised training organisations, or by completing the written exercise at the Customer Services Office (now named "Registration and Permit Office") located at EMSD Headquarters.

By October 2014, over 72,000 REWs had completed their training. The scheme is running smoothly and its first three-year training cycle was over by the end of 2014. To further enhance the effectiveness of the CPD scheme and deepen the continuous professional training culture in the electrical trade, EMSD conducted a review of the scheme in 2014. After considering the views from different stakeholders, it was decided that two new modes of training will be introduced in the second training cycle.

Starting from 1 January 2015, REWs can complete the required CPD training before applying for registration renewal through one of the following options:

Modes of training which remain valid:

1. Attending seminars organised by EMSD
2. Attending training courses organised by recognised training organisations
3. Completing the written exercise at the Registration and Permit Office (formerly "Customer Services Office") located at EMSD headquarters

New modes of training:

1. REWs who have taken or are taking academic courses related to electrical engineering recognised by EMSD and organised by training organisations such as local universities, Hong Kong Institute of Vocational Education, Vocational Training Council, etc. within the three-year period before the expiry date of the current registration certificate are regarded as having completed CPD training covering the two training modules. They should submit the official transcript or certificate issued by the relevant academic institution as proof when applying for registration renewal.
2. REWs who have become members in the electrical or building services discipline of some of the professional bodies in the engineering sector and have completed the mandatory continuing professional training required for their respective professional membership within the three-year period before the expiry date of the current registration certificate are regarded as having satisfied the CPD training requirement for REWs. They should submit documents (such as membership card) to prove their professional membership in the relevant period when applying for registration renewal.

The above two new modes of training not only allow REWs to continue their professional training through other means without having to repeat similar training, but can also help deepen the continuous professional training culture in the electrical trade.

Details of the CPD scheme, including the lists of recognised courses and professional bodies in the engineering sector, are available on EMSD website.

Feature Article 3 - Analysis of Electrical Incidents

Members of the electrical trade may be aware that there have been a number of serious electrical incidents in recent years in Hong Kong, resulting in fatalities from suspected electrocution. We are going to analyse some of these cases with a view to enhancing trade members' safety awareness when carrying out electrical work, and preventing electrical accidents from occurring.

Case 1

This incident happened in the bathroom of a domestic unit. A person was found lying dead in the bathtub during a shower. The cause of death was suspected to be electrocution. Investigation carried out by EMSD revealed that the equipotential bonding of the bathtub was mistakenly connected to the phase contact point of the fuse connection unit in the adjacent kitchen (see Figure 1), and the contact point was at the same time connected to a kitchen light unit. As a result, whenever the electric circuit for the kitchen lights was activated, the bathtub would be energised, leading in the end to the electrocution accident.

Case 2

This incident happened at a renovation site. A registered electrical worker was found lying dead on the floor while conducting modification works for the switch cubicle. The cause of death was suspected to be electrocution. Investigation carried out by EMSD revealed that the electrical worker had opened the backplate of the switch cubicle to carry out wiring work without disconnecting the power source completely. Unfortunately, the head of the electrical worker was suspected to have touched an energised bus bar on the ceiling of the switch cubicle when the modification works was in progress, resulting in the electrocution accident.

Case 3

This incident occurred at a construction site where a registered electrical worker was found lying on the floor during a fitting-out work conducted at height. The electrical worker was suspected to have died from falling from height after receiving an electric shock. An investigation by EMSD found that the electrical worker had touched a damaged cable wrapped only by adhesive tape while at work. Since the associated electric circuit was energised and the damaged part of the cable had not been properly wrapped up by the adhesive tape, the electrical worker received an electric shock after inadvertently touching the cable, and consequently fell from height.

Case 4

This incident occurred at a construction site where a construction worker was found lying on the floor during a fitting-out work. It was suspected that his equipment had an electricity leakage and he received a fatal electric shock as the protective device failed to function properly. An investigation by EMSD revealed that when the worker was using the mechanical breaker which received its power supply from a socket outlet, the equipment had an electricity leakage. Since the residual current circuit-breaker protecting the socket outlet was not installed properly, it failed to trip despite a leakage of electricity from the electrical appliance, resulting in the electric shock incident. For information regarding how to install a residual current circuit-breaker properly, please refer to "Proper Installation of Residual Current Operated Circuit-breaker with Integral Over-current Protection (RCBO)" under News-in-brief 1 in this issue.

Case 5

The incident occurred at the external wall of a building. A construction worker was found lying next to the signboard of a nearby construction site. He was suspected of dying from electrocution by coming into contact with the live parts of the signboard. After investigation by EMSD, it was revealed that the circuit of fluorescent tubes inside the signboard had an electricity leakage. The electrocution accident was the result of the earth wire of the signboard not being properly connected, and causing the metal casing and the relevant supporting frame of the signboard to be energised.

To conclude, the above incidents mainly occurred in construction sites, involving improper power suspension arrangement and poor workmanship. The followings are some of the suggestions on how to avoid the occurrence of electrical accidents:

1. The electrical work should be carried out by a registered electrical worker (REW) of the appropriate grade.
2. The scope of work and relevant circuits should be checked before carrying out the electrical work.
3. The conditions of the tools and instruments should be checked before carrying out the electrical work.
4. The metallic parts in the working environment should be tested to see if they are dead or energised before carrying out the work, while ensuring that appropriate personal protective equipment and tools are used (see Appendix 14 of the Code of Practice for the Electricity (Wiring) Regulations for details).
5. To avoid carrying out work under live conditions, the power supply of the installation should be cut off, isolated and locked out and the metallic parts of the installation should be tested to see if they are dead or energised before carrying out the electrical work.
6. If the work has to be performed under live conditions (such as testing), appropriate risk assessment should be made before carrying out the work (see Appendix 15 of the Code of Practice for the Electricity (Wiring) Regulations for details).
7. After completion of the electrical work and before the electrical installation is energised for use, the installation should be thoroughly checked (such as checking if all the disconnected earth wires have been reconnected), tested and certified by an REW to confirm that the requirements of relevant legislations have been met.

News-in-brief 1 - Proper Installation of Residual Current Operated Circuit-breaker with Integral Over-current Protection

Improper installation:

Figure 1 Not connected with earth wire

Figure 2 Not connected with neutral wire

Proper installation:

Figure 3 Connected with phase, neutral and earth wires

Under the Code of Practice for the Electricity (Wiring) Regulations, each circuit is required to be equipped with a protective device so that the circuit can automatically interrupt the electricity supply in the event of overcurrent resulting from overload or fault. The socket outlet circuit, in particular, must be protected with a residual current device.

Besides the general residual current devices (RCD), residual current operated circuit-breakers with integral over-current protection (commonly known as "RCBO" or "mouse tail") are also widely used by members of the electrical trade. Compared to the normal residual current devices which merely provide leakage protection, RCBO features an additional earth wire which provides earthing for the electronic circuits in the circuit breaker. If not connected to the earth wire (as shown in Figure 1), the integral over-current protection function of the circuit breaker may not be able to start the circuit breaker to shut off power supply when the neutral wire is cut off.

Meanwhile, there are members of the electrical trade who would install an RCBO the same way as they install a single phase miniature circuit breaker (MCB), i.e., without connecting the neutral wire to the RCBO (as shown in Figure 2). This may prevent the RCBO from performing its function of over-current protection.

The proper way of installing an RCBO is to connect all the phase, neutral, and earth wires to the circuit breaker (as shown in Figure 3). Electrical trade members who are in doubt should consult the installation manual provided by the circuit breaker manufacturer.

News-in-brief 2 - Safety Tips on Electrical Appliances

Household electrical products supplied in Hong Kong and operating at a voltage exceeding 50V a.c. or 120V d.c are regulated by the Electrical Products (Safety) Regulation (the Regulation). Under the Regulation, suppliers of household electrical products supplied for use in Hong Kong must ensure that their products have been issued with a valid certificate of safety compliance beforehand. Suppliers should obtain documentary proof from their supplying sources to confirm that the household electrical products have indeed been issued with certificates of safety compliance. It is important that suppliers should keep the relevant documentary proof for record purpose and for inspection by EMSD. However, the categories of persons that are regarded as suppliers and affected by the Regulation are many and varied. These include manufacturers, importers, wholesalers that supply electrical products designed for household use in Hong Kong; persons who sell or hire out household electrical products; and persons who give the household electrical products as a prize for commercial purpose or make a gift of such a product. EMSD has published the Guidance Notes for the Electrical Products (Safety) Regulation (the Guidance Notes), and uploaded it onto the web page for public reference.

Section B8 of Part 3 of the Guidance Notes stipulates the detailed requirements regarding valid certificates of safety compliance. The international standards applicable to some of the more common household electrical appliances are cited in item 1.2 of Section C1 of the Guidance Notes. Due to the innovations of household electrical appliances, please visit the web page of International Electrotechnical Commission for any information not covered in item 1.2 of Section C1 of the Guidance Notes.

On the other hand, the Regulation does not apply to the "travel adaptor", which is, as defined by the Regulation, an "adaptor" whose pins are not designed to engage with a socket in Hong Kong but which can connect with certain sockets in places outside Hong Kong and can be used in those places only. Generally speaking, any "adaptor" that can engage with a socket in Hong Kong must comply with the essential safety requirements and specific safety requirements set down in Schedule 1 and Schedule 2 of the Regulation respectively. As for electrical appliances used in Hong Kong, their "plugs" must also conform to BS1363 (3-rectangular-pin), BS546 (3-round-pin) or BS4573 (2-round-pin and should be used on sockets compliant with BS3535 standards) safety requirements. Neither 2-flat-pin "plugs" nor "adaptors" with irregular socket holes are in compliance with the relevant safety specifications. The relevant detailed requirements are also listed in the Guidance Notes.

News-in-brief 3 - Requirements for Attention in Installation of Earth Electrode

Registered electrical workers (REWs) and registered electrical contractors (RECs) should pay attention to the requirements regarding the installation of earth electrode specified in Section 12C (5) of the Code of Practice for the Electricity (Wiring) Regulations, which stipulates that the installation of earth electrode should comply with the Electricity Supply Lines (Protection) Regulation as appropriate.

The last few years saw a number of accidents resulting in injuries for workers when driving the copper rod electrode into the ground and causing damage to the underground cable during the installation of earth electrode. To prevent a repeat of such accidents, REWs should be aware that under general circumstances, if the installation of earth electrode involves excavation or ground penetration works, the working party should, before beginning work, adhere to the requirements of the Code of Practice on Working near Electricity Supply Lines and take all reasonable steps, including the appointment of a competent person approved by the Electrical and Mechanical Services Department to ascertain the alignment and depth of underground cables. During the course of work, all reasonable measures must be taken, such as maintaining a 500mm minimum safe working distance between the point of vertical penetration and the ascertained alignment of any underground cable, so as to comply with the Electricity Supply Lines (Protection) Regulation.

For more information, please refer to the Code of Practice on Working near Electricity Supply Lines available at our web page or the publicity leaflet "Protect Electricity Supply Lines Take All Reasonable Steps and Measures".

News-in-brief 4 - Notification of registration examinations for electrical workers

As stipulated in the Electricity (Registration) Regulations, electrical workers may acquire the academic qualifications to become Grade A, Grade B or Grade C registered electrical workers (REWs) by taking trade tests or examinations recognised by the Director of Electrical and Mechanical Services. The tests and examinations are detailed as follows:

For good environmental practice, REWs who have provided their email addresses will be notified of the dates of Grade B and Grade C registration examinations electronically. Information on the examination dates will also be published on our website about 3 months prior to the examination date. Electrical workers who do not have email addresses may browse our website or make enquiries direct with the organisers concerned.

News-in-brief 5 - Registered Electrical Workers and Contractors – Don't Miss the Deadline for Registration Renewal

The Electricity (Registration) Regulations stipulates that registered electrical workers (REWs) and contractors (RECs) should submit to the Electrical and Mechanical Services Department applications for registration renewal at least 1 month in advance, but no more than 4 months before the expiry date of the current registration. REWs and RECs are reminded again to apply for renewal of registration accordingly. Renewal applications submitted before or after the above-mentioned period may not be considered. Applications submitted after the expiry date of the current registration will be treated as new registration applications, and will be assessed in accordance with the statutory requirements of the day. These include requiring REWs applying for registration to possess recognised academic qualifications in electrical engineering and electrical work experience. If the applicant does not possess the required academic qualifications and thus is considered to be unable to fulfil the relevant registration requirements, the application will be rejected regardless of the previous registration history of the applicant.

In applying for registration renewal, the applicant is required to submit the duly completed Form 8 together with a copy of HKID card and a colour passport photograph with a plain white background, and pay the application fee. In addition, REWs are also required to have completed two modules of Continuing Professional Development training before submitting their renewal applications.

News-in-brief 6 - Customer Services Office Renamed Registration and Permit Office

The Customer Services Office located at the ground floor of EMSD Headquarters has been renamed Registration and Permit Office as from 3 November 2014. The office will continue to handle the registration applications of electrical workers / electrical contractors / competent persons, endorsement of periodic test certificates for fixed electrical installations, as well as the applications for other electrical and mechanical licenses and permits for which EMSD is responsible.

The Registration and Permit Office opens from Monday to Friday, from 9 am to 5:15 pm. It does not open on Saturday and Sunday and public holidays.

Electricity News Goes Paperless

News-in-Brief 7 - For good environmental practice, Electricity News will be posted to the registered email addresses of the registered electrical workers (REWs) and registered electrical contractors (RECs) as from the next issue. No printed copies will be posted anymore.

REWs or RECs who have not yet registered their email addresses, or who need to update us with their new email addresses are kindly requested to supply the information by completing "Personal Particulars" in "Readers Feedback" on the last page of Electricity News, and sending this back to the Electricity Legislation Division of EMSD by fax (28954929) or email (eld@emsd.gov.hk).

News-in-Brief 8 - Survey Questionnaire for Registered Electrical Workers

EMSD is currently conducting a survey of registered electrical workers (REWs) in order to have an up-to-date understanding of the industry. We ask for the cooperation of REWs to kindly complete the questionnaire in this issue of Electricity News. Completed questionnaires may be sent to the Electricity Legislation Division either by fax or email.

Electrical Safety Quiz

Readers Feedback

We look forward to receiving your valuable feedback about this newsletter for continuous improvement. Please complete the feedback form and return it to Electricity Legislation Division, EMSD by post, fax or e-mail (contact details at the bottom of this page) on or before 28 Feb 2015.

Contact Information

Electricity Legislation Division, EMSD, 3 Kai Shing Street, Kowloon, Hong Kong

1823

2895 4929

info@emsd.gov.hk