Optimizing power facilities in low-lying areas

Customers’ Flood Control Measures

To enhance the reliability and stability of the power transmission and distribution system, CEM regularly maintains and repairs the power supply system, including substations, medium-voltage network, low-voltage network, and the handover points to customer premises or offices/factories, which include public power distribution networks and associated power supply facilities. CEM also examines the customers’ building communal electrical installations at any time when necessary.

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Customer Substation

Power transmission and distribution network

Meter and Circuit breaker
(no higher than 34.5kVA)

The Revision of “Technical specifications for new building’s electrical installations in low-lying area”

In order to enhance the disaster prevention and resilience of new buildings in low-lying areas, CEM completed the revision of “Technical specifications for new building’s electrical installations in low-lying area” in September 2018 after communicating and coordinating with relevant departments.  It is mandatory to install electrical installations in new buildings, including transformers, main switchboards and meter boxes, above the flood prevention height level set by the Government to minimize the impact of flooding. In addition, CEM plans to relocate some of the customer substations at Porto Interior to a higher location, which can solve flooding problems in the long run and also provide more power capacity for the old districts.

Customers’ Responsibility:

For existing buildings, the customers’ building communal electrical installations (as shown below) are jointly owned by the building owners and generally installed on the ground floor at the building entrance. If customers do not raise such electrical installations accordingly, the power supply will still be affected by flooding.

To reduce the impact of flooding in the long run and achieve the best flood control effect, apart from the enhancement and upgrade of the electrical facilities done by CEM, building owners can also employ experienced electrical contractors to raise up the level of building communal electrical installations according to the above-mentioned “Technical specifications for new building’s electrical installations in low-lying area”, which will comprehensively improve the ability of disaster prevention and resilience of the building.

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Main Low Voltage Switchboard

Distribution Circuit Breaker

Collective line distribution board

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Building Main LV Circuit Breaker

Meter board

In addition, if the building is unfortunately affected by flooding during typhoon, building owners can employ an electrical contractor to inspect and repair the building communal electrical installations after the flood water receded, so as to restore the power supply and ensure the safe use of electricity as soon as possible.

How to raise electrical installations in your building?

Citizens or building owners who intend to raise their building’s power supply equipment, such as raising electrical installations at the ground floor to a higher position, will be determined according to the actual situation. Customers can hire an experienced electrical contractor and submit the related project application to CEM. We will assess and provide technical support for the design and installation of the related projects.

Customers can submit the application by sending email to customer.centre@cem-macau.com.

For inquiries about disaster prevention related to electricity, please call: 2833 9911

If you need to find an electrical contractor, please contact the electrical technician in the “Electrical Contractor List” to consult and learn about project details and related services provided by them.


Generally speaking, the tasks involved in raising the meter and preventing building communal electrical installations from flooding include:

  1. Reallocate to a position above the prevention of flood height level of +4.21msl
  2. Raise installation level, need to check site condition while taking existing building limitations and without affecting operational and safety requirements into account.
  3. Provide individual design for approval and indicate:
    i) The location of main collective panel;
    ii) Power cables between pothead and main collective panel or main collective panel and CCL (including necessary civil works) may need to be reinstalled.
  4. During the upgrade period of main collective panel, CEM can provide temporary power supply under customers’ request.
  5. Ensure that the power cable connected to inlet is waterproof, which can further enhance waterproof performance.