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r Code of Practice for Energy Efficiency of Electrical Installations, 2007


i

Foreword

The Code of Practice for Energy Efficiency of Electrical Installations aims to set out the
minimum

requirements on energy efficiency of electrical installations. It forms a part of a set of
comprehensive
Building Energy Codes
that address energy efficiency requirements on building
services installations. Designers are encouraged to adopt a proactive approach to exceed the
minimum requirements.

The
Building Energy Codes
were developed by ad hoc task forces under the Energy
Efficiency & Conservation Sub-committee of the Energy Advisory Committee. The set of
comprehensive
Building Energy Codes
cover this Code, the Codes of Practice for Energy Efficiency
of Lighting Installations, Air Conditioning Installations, and Lift & Escalator Installations, and the
Performance-based Building Energy Code.

To promote the adoption of the
Building Energy Codes
, the Hong Kong Energy Efficiency
Registration Scheme for Buildings was also launched. The Registration Scheme provides the
certification to a building complying with one or more of the
Building Energy Codes
.

To supplement and further explain the codes, corresponding Guidelines were also
published.









Amendment


The Code was first published in 1998. To suit changes in technological advancement and
to cope with trade practices, there have been amendments to the first published edition, which
were agreed in code review task forces with members from representative organizations in the
building industry including professional institutes, trade associations and the academia.


In 2003, the requisite requirement on compliance with the other three Codes were waived,
the maximum allowable copper loss requirement on domestic buildings was relaxed, the maximum
allowable THD requirement on lift & escalator circuit was waived should the Lift & Escalator Code
was already complied, and the position of power factor correction device not right at the source
was conditionally permitted.


In 2007, the Minimum Motor Efficiency requirements are upgraded (Table 5.1 in Code);
Maximum Allowable Copper Loss requirements for exceedingly lengthy circuits conditionally
relaxed (in Clause 4 of Code); requirement on using synchronous belts in power transfer devices
(previous Clause 5.4.4) waived; and a performance requirement as an alternative to THD
compliance (at end of Clause 6.1) introduced.



Copyright

This Code is copyrighted and all rights (including subsequent amendment) are reserved.



The Building Energy Codes and Registration Scheme documents are available for download
at
http://www.emsd.gov.hk/emsd/eng/pee/eersb.shtml

Enquiry: hkeersb@emsd.gov.hk
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N Code of Practice for Energy Efficiency of Electrical Installations


ii

CONTENTS













Page
1. SCOPE ......................................................................................
1
2. DEFINITIONS .............................................................................
1
3. GENERAL APPROACH ...............................................................
3
4. ENERGY EFFICIENCY REQUIREMENTS FOR POWER DISTRIBUTION IN
BUILDINGS
4
4.1 High Voltage Distribution ...................................................................
4.2 Minimum Transformer Efficiency ........................................................
4.3 Locations of Distribution Transformers and Main LV Switchboard .......
4.4 Main Circuits .....................................................................................
4.5 Feeder Circuits ...................................................................................
4.6 Sub-main Circuits...............................................................................
4.7 Final Circuits ......................................................................................
4
4
4
4
4
5
5
5. REQUIREMENTS FOR EFFICIENT UTILISATION OF POWER
6
5.1 Lamps and Luminaires........................................................................
5.2 Air Conditioning Installations .............................................................
5.3 Vertical Transportation .......................................................................
5.4 Motors and Drives..............................................................................
5.5 Power Factor Improvement ................................................................
5.6 Other Good Practice
..................................................................................
6
6
7
7
8
8
6. ENERGY EFFICIENCY REQUIREMENTS FOR POWER QUALITY
9
6.1 Maximum Total Harmonic Distortion (THD) of Current on LV Circuits..
6.2 Balancing of Single-phase Loads.........................................................
9
10
7. REQUIREMENTS FOR METERING AND MONITORING FACILITIES
10
7.1 Main Circuits..........................................................................................
7.2 Sub-main and Feeder Circuits.................................................................
10
10
8. SUBMISSION OF IMFORMATION ................................................
10


Electrical Forms :

FORM EL-1 : Electrical Installations Summary ....................................................
11
FORM EL-2 : Electrical Power Distribution Worksheet........................................
12
FORM EL-3 : Electrical Power Utilisation Worksheet ..........................................
15
FORM EL-4 : Electrical Power Quality Worksheet...............................................
17
FORM EL-5 : Electrical Metering & Monitoring Worksheet.................................
19


Appendix :

A : Explanatory Notes and Sample Calculations.................................................
20
B : Case Study for a Typical Commercial Building in Hong Kong........................
29 Code of Practice for Energy Efficiency of Electrical Installations


page 1 of 35
1. SCOPE

1.1

The Code shall apply to all fixed electrical installations, other than those used as
emergency systems, for all buildings except those specified in Clause 1.2, 1.3 and
1.4 below.

1.2

The following types of buildings does not come under the scope of control of this
Code:

(a)
buildings with a total installed capacity of 100A or less, single or three-
phase at nominal low voltage; and

(b)
buildings used solely for public utility services such as power stations,
electrical sub-stations, water supply pump houses, etc.

1.3

Buildings designed for special industrial process may be exempted partly or wholly
from the Code.

1.4
Equipment owned by the public utility companies (e.g. HV/LV switchgear,
transformers, cables, extract fans, etc.) and installed in consumers substations will
not be gvverned by the Code.

1.5
In case where the compliance of this Code is in conflict with the safety
requirements of the relevant Ordinance, Supply Rules, or Regulations, the
requirements of this Code shall be superseded. This Code shall not be used to
circumvent any safety, health or environmental requirements.



2. DEFINITIONS

The expressions, which appear in this Code, are defined as follows:-

Appliance means an item of current using equipment other than a luminaire or an
independent motor or motorised drive.

Appliance, fixed means an appliance, which is fastened to a support or otherwise secured
at a specific location in normal use.

Appliance, portable means an appliance which is or can easily be moved from one place
to another when in normal use and while connected to the supply.

Building means any building as defined in Building Ordinance Cap. 123.

Circuit, feeder means a circuit connected directly from the main LV switchboard to the
major current-using equipment.

Circuit, final means a circuit connected from a local distribution board to a current-using
equipment, or to a socket-outlet or socket-outlets or other outlet points for the connection
of such equipment.

Circuit, main means a circuit connected from a distribution transformer to the main LV
switchboard downstream of it.
Code of Practice for Energy Efficiency of Electrical Installations


page 2 of 35
Circuit, sub-main means a circuit connected from the main LV switchboard or a rising
mains to a local distribution board.

Communal installation means an installation provided by the building owner as part of
the services to the tenants or to comply with a particular statutory requirement.

Distribution transformer means an electromagnetic device used to step down electric
voltage from high voltage distribution levels (e.g. 11kV) to the low voltage levels (e.g.
380V), rated from 200kVA, for power distribution in buildings.

Effective current-carrying capacity means the maximum current-carrying capacity of a
cable that can be carried in specified conditions without the conductors exceeding the
permissible limit of steady state temperature for the type of insulation concerned.

Emergency system means any statutory required system, which is installed for the
purpose of fire services as defined in Co