Where any of the following installations is required by this Code or other Codes/ Regulations, its primary and secondary source of power supply shall comply with the corresponding Code of Practice stated therein.

a. Electrical lifts

Where an electrical passenger or goods lift is required, its electrical installations, including batteries and other forms of secondary power supply, shall comply with SS 550. Where the provision of fire lift is required by this Code, installation of the primary and secondary supplies shall also comply with the above-mentioned Code of Practice.

b. Electrical fire alarm system

Where electrical fire alarm system is required, its primary power supply as well as its type and capacity of battery shall comply with SS 645.

c. Exit light and emergency lighting systems

Where exit or emergency lighting system is required, its electrical wiring, type and capacity of battery or other form of secondary power supply shall comply with SS 563.

d. Emergency voice communication system

Where an emergency voice communication system is required, its electrical wiring shall be fire-rated or otherwise fire-protected in accordance with SS 546. The appropriate type and capacity of secondary source of supply shall also be provided accordingly.

e. Fire sprinkler system

Installation of electrical supply for sprinkler systems shall comply with SS CP 52. The capacity of the secondary source of supply, where required, shall satisfy operational requirements under the respective hazard category.

f. Mechanical ventilation/ pressurisation systems

All the following systems shall be provided with secondary source of power supply:

(1) Mechanical ventilation system for the following rooms or spaces:

(a) exit staircases;

(b) exit passageways;

(c) smoke-free/ fire lift lobbies;

(d) area of refuge within the same station;

(e) basement car parks;

(f) fire command centres;

(g) emergency power generator rooms;

(h) fire pump rooms;

(i) under-platform exhaust where required to operate during a fire emergency;

(j) emergency ventilation system of underground or enclosed trainway; and

(k) any other areas where such systems are installed for fire precautionary measures.

(2) Pressurisation systems for the following areas:

(a) smoke-free/ fire lift lobbies;

(b) internal exit staircases; and

(c) any other areas where such systems are installed.

(3) All smoke control/ purging systems, including associated equipment forming part of the systems.

g. Air supply system for generator and fire pump

A secondary source of power supply shall be provided for the mechanical ventilation system which is installed to provide air for the operation of the following equipment:

(1) emergency generator; and

(2) engine driven fire pump.

The installation of cable in stations and trainways shall comply with all the following:

a. Cables used shall be either fire retardant or fire resistant. In addition, cables used in underground rapid transit systems shall be of the low-smoke and halogen-free type.

b. Fire resistant cables shall comply with SS 299 and fire-resistant fibre optic cable shall comply with IEC 60331-25.

c. Fire retardant cables shall comply with IEC 60332 Part 1 & 3 on tests on single and bunched cables under fire conditions.

d. Low-smoke and halogen-free cables shall comply with the following requirements:

(1) IEC 61034.

(2) When a sample of cable is subjected to the combustion test to determine amount of halogen acid gases (other than hydrofluoric acid) set out in IEC 60754 - Part 1, and the amount of halogen acid evolved is less than 0.5%, the cable shall be regarded as halogen free.

e. Fire resistant/ flame retardant, low smoke zero halogen (LSOH) type cables are permitted to be run exposed in air plenum, provided that:

(1) The air plenum shall be protected by fire detection system. 

(2) FCU or AHU using plenum for air return and serving more than one room shall be provided with smoke detector(s) at the return air plenum or return air duct to shut down the FCU/ AHU upon detection of smoke.

Cables for fire safety equipment that is required to operate during a fire emergency shall be of fire-resistant type.

Exception: Internal cables of control panels/ equipment, lifts and its cables, and light fittings.

All motors and their control equipment, as well as the associated wiring and accessories, shall be suitable for their particular application and for the environment they are exposed to. In addition, they shall comply with all the following requirements:

a. Moulded Case Circuit Breakers (MCCB) with magnetic release shall be installed and be capable of protecting the cable connections to the motor, and of carrying the stalled current of the motor for a period not less than 75% of the period for which such a current would cause the motor windings to fail;

b. any no-volt release mechanism shall be of the automatic resetting type, such that on restoration of supply the motor can start automatically;

c. thermal overload trips shall not be permitted; and

d. magnetic (short circuit) trips are permitted for use in motor circuits of mechanical ventilation systems serving essential services.

a. Where emergency generators are provided as a secondary source of supply, they shall comply with SS 535.

b. For outdoor emergency generator, all the following requirements shall be complied with:

(1) Day tank incorporated within the body of the emergency generator shall be constructed of steel. The day tank shall be of double skin construction. The emergency generator enclosure shall be able to contain any leakage of diesel.

(2) Alternatively, an internal bund wall shall be built within the outdoor emergency generator’s day tank large enough to contain 100% of the diesel content within the day tank.

(3) The maximum quantity of diesel permitted in the day tank is 1000 litres.

Dual electric feeder power supply is deemed to have been provided with primary and secondary source of power supplies, on condition that the feeders are tapping power supply from different segregated blocks of the power grid. The primary feeder (primary supply) shall be the normal power supply while the secondary feeder (secondary supply) shall be the emergency power supply. See Diagrams 5.2.6 – 1 & 2 below.

Uninterruptible power supply (UPS) consisting of centralised batteries can be considered as a secondary source of power supply.

Diagram 5.2.6 – 1: Block diagram of Typical RTS Station Dual Feeder LV Power Supply Scheme

Diagram 5.2.6 – 2: Block diagram of Typical RTS Station Dual Feeder HT Power Supply Scheme