<h3>What makes up a CU</h3>
<p>The consumer unit (CU) is an electrical distribution panel installed in the flat. It is housed in an enclosure comprising:</p>
<ul>
    <li>Double pole Miniature Circuit Breakers (MCBs)</li>
    <li>Residual Current Circuit Breaker (RCCB)</li>
    <li>Outgoing single pole MCBs</li>
    <li>Terminals</li>
</ul>
<p>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.</p>
<p>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).</p>
<h4>Miniature Circuit Breakers (MCBs)</h4>
<p>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 &lsquo;trip&rsquo; to cut the supply to the circuit. A single pole MCB protects a single electrical circuit.</p>
<h4>Residual Current Circuit Breaker (RCCB)</h4>
<p>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.</p>
<p>Here are maintenance tips you can follow:</p>
<ul>
    <li>Test the RCCB monthly to ensure that it is working</li>
    <li>Switch off all sensitive equipment such as computers before the test</li>
    <li>Engage a licensed electrician to replace the RCCB if it malfunctions</li>
</ul>
<p><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/mcbandrccb.jpg" alt="MCB and RCCB" /></p>
<table>
    <thead>
        <tr>
            <th>MCB Tripped</th>
            <th>RCCB Tripped</th>
        </tr>
    </thead>
    <tbody>
    </tbody>
</table>

Consumer unit (CU)

<h3>How to check a plug</h3>
<p>Ensure that the flexible (2-core or 3-core) cable on your appliance is in good condition and is not cut or twisted.<br />
There are 3 terminal holes in the plug where the correct core of flexible cable wire should be terminated.</p>
<table>
    <thead>
        <tr>
            <th>Parts of Plug</th>
            <th>Image</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>Terminal hole marking
            <ul>
                <li>L (&lsquo;Live&rsquo;, also known as &lsquo;Phase&rsquo;)</li>
                <li>N (&lsquo;Neutral&rsquo;)</li>
                <li>E (&lsquo;Earth&rsquo;, also known as &lsquo;Protective&rsquo;)</li>
            </ul>
            </td>
            <td><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/plug-terminal-hole-marking.jpg" alt="plug terminal hole marking" /></td>
        </tr>
        <tr>
            <td>Core colour of flexible cable
            <ul>
                <li>L: Brown</li>
                <li>N: Blue</li>
                <li>E: Green and yellow</li>
            </ul>
            </td>
            <td><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/plug.jpg" alt="plug" /></td>
        </tr>
        <tr>
            <td>Fuses
            <ul>
                <li>A 13 Ampere plug should be fitted with a 13 Ampere fuse</li>
            </ul>
            </td>
            <td><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/fuse.jpg" alt="fuse" /></td>
        </tr>
    </tbody>
</table>
<h3>Maintenance tips</h3>
<ul>
    <li>Avoid overloading socket outlets</li>
    <li>Ensure cables are not cut or broken</li>
    <li>Unplug equipment when not in use</li>
</ul>
<h3>Common problems and solutions</h3>
<p>Learn about the common issues you may encounter, why they happen, and how to fix them.</p>
<h4>No power supply to the appliance</h4>
<p><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/electrical-plug-interior.jpg" alt="electrical plug interior" /></p>
<ul>
    <li>Why this happens:
    <ul>
        <li>Blown fuse</li>
        <li>Loose connection</li>
        <li>Faulty appliance</li>
    </ul>
    </li>
    <li>Solutions:
    <ul>
        <li>Change new fuse with correct rating</li>
        <li>Tighten all terminators</li>
        <li>Send faulty appliance for repair</li>
    </ul>
    </li>
</ul>
<h4>Overheated plugs in socket outlet or frequently blown plug fuse</h4>
<p><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/electrical-plugs.jpg" alt="electrical plugs" /></p>
<ul>
    <li>Why this happens:
    <ul>
        <li>Loose connection</li>
        <li>Overloaded circuit</li>
        <li>Cable is broken</li>
    </ul>
    </li>
    <li>Solutions:
    <ul>
        <li>Ensure plugs are fully connected to the adaptor</li>
        <li>Disconnect unnecessary appliances</li>
        <li>Engage a licensed electrician to check cable</li>
    </ul>
    </li>
</ul>
<h4>Burnt mark at the socket outlet</h4>
<p><img src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-socket.jpg" alt="wall socket" /></p>
<ul>
    <li>Why this happens:
    <ul>
        <li>Plug is not properly inserted</li>
        <li>Overloaded circuit</li>
    </ul>
    </li>
    <li>Solutions:
    <ul>
        <li>Ensure plug touches the base of the socket outlet</li>
        <li>Reduce the number of plugs used on 1 socket outlet</li>
    </ul>
    </li>
</ul>

Electrical accessories

<p>Your flat&rsquo;s electrical wiring has a limited lifespan. The estimated average lifespan of a PVC electrical cable is approximately 25 years.</p>
<p>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. </p>
<p>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.</p>

Electrical wirings

<h3>Clean the fan blades</h3>
<p>You should clean your fan at least once a month. Remember to remove the front grille if you are cleaning a wall-mounted fan.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-fangrille1.jpg" /></p>
<p>You can quickly remove thin layers of dust by cleaning the fan blades with a vacuum cleaner and brush attachment.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-fanvacuum2.jpg" /></p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/ceiling-fanvacuum3.jpg" /></p>
<p>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.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-fancloth5.jpg" /></p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/ceiling-fancloth4.jpg" /></p>
<p>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.</p>
<h3>Tighten all screws</h3>
<p>Loose screws can result in noisy or shaky fans.</p>
<p>The screws on the fan may loosen over time due to the fan&rsquo;s vibrations. Simply tighten any screws with a screwdriver, particularly those on the fan, ceiling plate, and light fixture, if any.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-fantighten-screw7.jpg" /></p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/ceiling-fantighten-screw6.jpg" /></p>
<h3>Noisy fans</h3>
<p>Noise from ceiling or wall-mounted fans can disturb your neighbours, especially low-humming or intermittent sounds.</p>
<h3>Humming Noise</h3>
<p>For most cases, you can resolve the humming noise by lubricating the fan with light machine oil.</p>
<p>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.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/wall-fanrubber8.jpg" /></p>
<h3>Intermittent Noise</h3>
<p>Intermittent noise may be caused by loose fan blades or screws. You can address this by tightening the screws.</p>
<p><img alt="" src="/-/media/managing-my-home/renovation-and-maintenance/home-maintenance/home-care-guide/electrical-accessories-and-wiring/ceiling-fantighten-screw9.jpg" /></p>
<p>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.</p>

Maintaining Electrical Accessories and Wiring in HDB Flats