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Residential

Electrical Accessories and Wiring

Learn how the electrical accessories and wiring function and get some maintenance tips to keep them in good working condition.

Consumer unit (CU)

The CU distributes electricity within your flat. Proper maintenance will ensure safe electricity distribution throughout your home.

What makes up a CU

The consumer unit (CU) is an electrical distribution panel installed in the flat. It is housed in an enclosure comprising:

  • Double pole Miniature Circuit Breakers (MCBs)
  • Residual Current Circuit Breaker (RCCB)
  • Outgoing single pole MCBs
  • Terminals

One of the double pole MCBs will function as the main switch of the CU. The other double pole MCB will function as the main switch for the Household Shelter (HS) in the flat, where applicable.

The maximum current that can be drawn through a CU is limited by the rating shown on the double pole MCB (main switch of the consumer unit).

Miniature Circuit Breakers (MCBs)

MCBs are designed to protect against overheating of electrical cables and appliances. In the event of overcurrent due to an overload or short-circuit, the MCB will ‘trip’ to cut the supply to the circuit. A single pole MCB protects a single electrical circuit.

Residual Current Circuit Breaker (RCCB)

A major component of the CU is the Residual Current Circuit Breaker (RCCB), which is a safety circuit breaker. It automatically cuts off electricity in your flat when it detects an earth current leakage in an electrical circuit. The RCCB has a test button, labelled T. When it is pressed, the RCCB should switch off automatically. If not, the RCCB may be defective. If the RCCB is in working condition, reset the RCCB after testing.

Here are maintenance tips you can follow:

  • Test the RCCB monthly to ensure that it is working
  • Switch off all sensitive equipment such as computers before the test
  • Engage a licensed electrician to replace the RCCB if it malfunctions

MCB and RCCB

MCB Tripped RCCB Tripped
Scenario 1: MCB can be reset
  • Why this happens:
    • Faulty appliance
    • Overloaded circuit
  • Solution:
    • Disconnect faulty appliance from the socket outlet
    • Disconnect appliance that causes overloading
Scenario 1: RCCB can be reset
  • Why this happens:
    • Faulty appliance
    • Faulty RCCB
    • Faulty cable
  • Solution:
    • Engage a licensed electrician to check the RCCB and cable
    • Send faulty appliance for repair
Scenario 2: MCB cannot be reset
  • Why this happens:
    • Cable shorted
    • Faulty appliance
  • Solution:
    • Engage a licensed electrician to change the wiring or send the faulty appliance for repair
Scenario 2: RCCB cannot be reset
  • Why this happens:
    • Live cable touches metal parts
    • Faulty appliance
    • Cables are wrongly connected
  • Solution:
    • Engage a licensed electrician to change the wiring or send the faulty appliance for repair

 

Electrical accessories

Plugs and socket outlets are common household electrical accessories. Only a licensed electrician can replace socket outlets.

How to check a plug

Ensure that the flexible (2-core or 3-core) cable on your appliance is in good condition and is not cut or twisted.
There are 3 terminal holes in the plug where the correct core of flexible cable wire should be terminated.

Parts of Plug Image
Terminal hole marking
  • L (‘Live’, also known as ‘Phase’)
  • N (‘Neutral’)
  • E (‘Earth’, also known as ‘Protective’)
plug terminal hole marking
Core colour of flexible cable
  • L: Brown
  • N: Blue
  • E: Green and yellow
plug
Fuses
  • A 13 Ampere plug should be fitted with a 13 Ampere fuse
fuse

Maintenance tips

  • Avoid overloading socket outlets
  • Ensure cables are not cut or broken
  • Unplug equipment when not in use

Common problems and solutions

Learn about the common issues you may encounter, why they happen, and how to fix them.

No power supply to the appliance

electrical plug interior

  • Why this happens:
    • Blown fuse
    • Loose connection
    • Faulty appliance
  • Solutions:
    • Change new fuse with correct rating
    • Tighten all terminators
    • Send faulty appliance for repair

Overheated plugs in socket outlet or frequently blown plug fuse

electrical plugs

  • Why this happens:
    • Loose connection
    • Overloaded circuit
    • Cable is broken
  • Solutions:
    • Ensure plugs are fully connected to the adaptor
    • Disconnect unnecessary appliances
    • Engage a licensed electrician to check cable

Burnt mark at the socket outlet

wall socket

  • Why this happens:
    • Plug is not properly inserted
    • Overloaded circuit
  • Solutions:
    • Ensure plug touches the base of the socket outlet
    • Reduce the number of plugs used on 1 socket outlet

Electrical wirings

You are advised to replace your flat’s electrical wiring when its lifespan is over or when it is worn out.

Your flat’s electrical wiring has a limited lifespan. The estimated average lifespan of a PVC electrical cable is approximately 25 years.

You are advised to replace the electrical wiring in your flat when its lifespan is over or when its condition has deteriorated. A licensed electrical worker (LEW) will be able to check the conditions of the wirings and advise whether the wiring needs to be replaced. 

When carrying out the electrical re-wiring and on completion, your appointed LEW is required to submit an SP Services Ltd (SPSL) form CS/5H endorsed by us to SPSL and apply for testing of the completed works.

Ceiling and Wall-mounted Fan

Regular maintenance of your ceiling or wall-mounted fan is important to keep them running smoothly.

Clean the fan blades

You should clean your fan at least once a month. Remember to remove the front grille if you are cleaning a wall-mounted fan.

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You can quickly remove thin layers of dust by cleaning the fan blades with a vacuum cleaner and brush attachment.

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For thicker layers of dust, wipe the top and bottom of each fan blade with a damp cloth.  Avoid shaking or bending the fan blades excessively to prevent damage.

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Do not use ammonia or bleach-based cleaners or any harsh cleaners to clean the fan, as this may wear away its surface finish and cause warping to the fan blades.

 

Tighten all screws

Loose screws can result in noisy or shaky fans.

The screws on the fan may loosen over time due to the fan’s vibrations. Simply tighten any screws with a screwdriver, particularly those on the fan, ceiling plate, and light fixture, if any.

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Noisy fans

Noise from ceiling or wall-mounted fans can disturb your neighbours, especially low-humming or intermittent sounds.

Humming Noise

For most cases, you can resolve the humming noise by lubricating the fan with light machine oil.

If the humming noise persist after lubricating the fan, you may need to consult a reliable fan supplier/ installer to install an insulation pad (such as a fan rubber) to the base of the fan or to repair the fan.

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Intermittent Noise

Intermittent noise may be caused by loose fan blades or screws. You can address this by tightening the screws.

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If the intermittent noise persist, it could be caused by the deterioration of the rubber holding the fan. You will need to consult a reliable fan supplier/ installer to replace it.