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Blog - Understanding the Consumer Unit (CU) in Singapore and How to perform Electric Troubleshooting

Understanding the Consumer Unit (CU) in Singapore and How to perform Electric Troubleshooting
By Gerald Peck 8/19/2016 12:09 PM

Within every HDB or Condo in Singapore, you’ll find a consumer unit (CU) which is an electrical distribution panel. Understanding how it functions and how to maintain it is very important to keep it in optimum condition. There might be the time where you need to perform electric troubleshooting


Within the CU, you’ll find the following components:

- Double pole miniature circuit breakers (MCBs)

- Outgoing single pole MCBs

- Residual current circuit breaker (RCCB)

- Terminals


One of the double pole MCBs serves as the main switch for your CU, while the other one is the main switch for the household shelter (HS) in your flat. On the double pole MCB, which is the main switch to the consumer unit, you’ll find a rating that will show the maximum current that can be pulled through the CU>


Miniature Circuit Breakers (MCBs)

The purpose of the MCBs is to protect the CU from overheating the electrical wiring and appliances. Should there ever be an over current causes it the CU to short circuit, the MCB will cut off the power supply to the circuit. The single pole MCV protects the circuit. 


Residual Current Circuit Breaker (RCCB)

This is the most major component of the CU. It’s a safety circuit breaker that automatically shuts off the electric in your flat when it senses a leakage in one of your electrical circuits. This circuit breaker has a special test button with a “T” on it. When you press it, the RCCB should turn off automatically. If you press it and nothing happens, it is a good indication that the RCCB may be defective. After you test it, you’ll need to remember to reset it. 

Residual Current Circuit Breaker (RCCB) 



Maintenance Tips and Electric Troubleshooting Singapore

To keep things in operational condition, test the RCCB monthly. Make sure you turn off sensitive electronic items like your computer before you run any tests. 


If the MCB has been tripped, you have 2 likely scenarios. In the first, you can reset the MCB. This is most commonly caused by a faulty appliance or an overloaded circuit. You can disconnect the faulty appliance from the outlet. And if a particular appliance is causing the overloading, remove it from the circuit. The second scenario occurs when you cannot reset the MCB. This would be due to a shorted cable or even a faulty appliance could burn it out. You’ll need to hire a licensed electrician to help sort it out.


If the RCCB has been tripped, there are 2 likely scenarios here as well. If it can be reset, it is likely caused by a faulty appliance, a faulty RCCB or a faulty cable. And if it can’t be resent, it’s likely due to a live cable touching metal parts, faulty appliance or cables that have been incorrectly connected. For either of these scenarios, it is best for you to hire a licensed electrician to handle the problem. 


If you’re having electrical problems, let ISOHomeCare help you find a qualified electrician today!