LOAD DISTRIBUTION AND FINAL DB WIRING

Phase-wise Load Distribution may possibly be during Final DB (Distribution Board) wiring. Equally load distribution in the final DB or physical load connected to an electrical circuit is important to keep the load balanced in each of the three phases.

Importance of Load Distribution in Final DB

All loads of premises become connected electrically through the final DB. Equally distributing the load on phase Read, Yellow, and Blue; it’s promising better performance of other accessories like protective devices RCD, Circuit Breaker, switches, fuses, cables, etc.

RCD for Earth Leakage Protection

Earth Leakage: Electricity is carried by conductors that are supported above the earth or inside the earth but are electrically isolated by insulators which prevent the electricity from neutralizing itself as it would if it shorted to earth. However, there is some very small leakage across these insulators, especially aerial insulators during wet or humid conditions. This is called earth leakage.

RCD for the three-phase system should have a residual current device (RCD-TP) of sensitivity not exceeding 100 mA. If there is no three-phase load in the installation, it is better to use three units (RCD-SP) of single-phase RCCBs to be installed. This will reduce the interruption when a single phase fault occurs.

Properly rated Residual Current Devices (RCD) must be used for protection from earth leakage currents to prevent electric shocks. For a power circuit RCD sensitivity should be 30mA, for sensitive load like water heater RCD sensitivity should be 10mA.

In any place of public entertainment, children school, where the floor is likely to be wet or where the wall or enclosure is of low electrical resistance, protection against earth leakage current must be provided by a RCD of sensitivity 10mA.

Any hand-held equipment, apparatus, or appliance installation must ensure protection against earth leakage current provided by an RCD of sensitivity 30mA.

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Main and Earth Conductor and Accessories

For light circuits load should keep within 1800 watts, if contactor control is used for lighting circuits, loading may be increased to 7 KW per circuit. Both main and earth conductors should be the same sizes, normally used sizes are 1.5 & 2.5 sqm cable.

For connection between the ceiling rose and lamp holders pendant type light fittings should be used heat resisting flexible cords, these cords may be insulated with butyl rubber, EP, rubber, silicone rubber, or glass fiber.

Typically used Circuit Breaker (CB) capacity for the final circuit is 6A, 10A, 16A, etc.

Every domestic wiring installation needs final DB wiring with load distribution, ensuring control and protection separating/isolating, and switching together with the protection of the system.

PROCEDURE OF LOAD DISTRIBUTION  IN THE DISTRIBUTION BOARD

Load distribution in a distribution board is the process of properly allocating and distributing electrical loads among the circuits and breakers in the distribution board. This ensures that the electrical system operates safely and efficiently without overloading any individual circuit or the overall system. Here are some tips for load distribution in a distribution board:

Determine the total load: Calculate the total electrical load that will be connected to the distribution board. This includes all the appliances, lighting, equipment, and other electrical devices that will be powered from the board.

Know the capacity of the board: Understand the maximum current-carrying capacity of the distribution board. This information is usually provided on the board itself or in the manufacturer's documentation. It is important not to exceed the rated capacity of the distribution board to prevent overheating or electrical hazards.

Plan the circuit layout: Divide the total load into multiple circuits based on the electrical requirements of the connected devices. Consider the type of load (lighting, appliances, etc.), power ratings, and expected usage patterns.

Use circuit breakers effectively: Install circuit breakers of appropriate ratings for each circuit. Circuit breakers protect the circuits from overloads and short circuits. Assign circuit breakers according to the expected load of each circuit, ensuring they are not overloaded.

Balance the loads: Distribute the loads evenly across the circuits to achieve a balanced distribution. Avoid situations where one circuit is heavily loaded while others remain underutilized. This helps prevent overloading of individual circuits and improves the overall efficiency of the electrical system.

Consider diversity factors: Take into account the diversity of the connected loads. Some appliances or equipment may not operate simultaneously or have varying usage patterns. Use diversity factors to calculate the actually expected load on each circuit, considering the likelihood of simultaneous operation.

Monitor and review: Regularly monitor the load distribution and review the performance of the circuits. If necessary, make adjustments to the distribution of loads based on changes in requirements or any identified issues.

Seek professional assistance: If you are unsure about load distribution or dealing with complex electrical installations, it is recommended to consult a qualified electrician or electrical engineer who can provide guidance and ensure compliance with safety standards and regulations.

Proper load distribution in a distribution board is essential for maintaining the electrical system's safety and efficiency. By following these tips and adhering to electrical codes and regulations, you can ensure a well-balanced and optimized distribution of loads in your distribution board.