Understanding Your DB Board’s Core Components
Inside your DB board are essential devices that control and protect your home’s electrical circuits:
Circuit Breakers: Your Resettable Fuses
A circuit breaker performs the same function as a traditional fuse but offers a significant advantage: it only needs to be reset, not replaced. These crucial safety devices have largely replaced fuses in modern installations.
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How They Work: Circuit breakers are chosen with a rating slightly less than the maximum current a circuit can safely handle. When the current flow in a circuit exceeds this rating (due to an overload or short circuit), the breaker will “trip,” automatically cutting off the electricity supply to that circuit. This protects your wiring and appliances from damage.
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Restoring Power: Once the fault has been cleared (e.g., by unplugging the overloaded appliance), the circuit breaker can be manually reset, restoring the supply.
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Location & Labeling: Circuit breakers are located in your building’s distribution board and sometimes in the utility supply meter box. Every breaker should be clearly labelled (e.g., “Lights,” “Plugs,” “Geyser,” “Stove”) so faulty circuits can be easily identified and isolated. A circuit breaker also doubles as a manual switch.
Switches and Isolators: Controlling the Flow
Switches and isolators are devices specifically designed to safely break the flow of current. While they come in various shapes and sizes, they all operate on the same principle.
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Importance of Rating: An important factor when choosing any switch is its current and voltage rating. Reputable manufacturers always indicate these operating limits. For instance, a light switch must never be used as a stove isolation switch. The rating of the light switch would be far too low for the stove’s high current draw, causing it to overheat and fail, potentially leading to a fire.
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Common Locations: In a residential building, switches include those within the distribution board (like your main isolator) and common wall switches controlling lights and power outlets.
Earth Leakage Unit (ELU): Your Lifesaver
An Earth Leakage Unit (ELU), also known as a Residual Current Device (RCD), is perhaps the most vital safety feature in your DB board. It is specifically designed to detect even small imbalances between the live and neutral conductors, indicating that electricity is “leaking” out of the system – typically to earth, through a person, or a faulty appliance.
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How it Protects You: When this leakage happens, the earth leakage switch automatically turns off or “trips” within milliseconds, cutting off the electricity supply. This rapid response is crucial for preventing severe electric shocks and electrical fires.
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Regular Testing is Essential: A small test button is provided on your ELU. It should be used to test the unit periodically (usually monthly) to ensure it’s functioning correctly. This simple test can save lives. An ELU should always be installed in any electrical installation.
