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Distribution Boxes: Types and Functions

Distribution Box

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The distribution box serves as the load centre and distributor of electrical power.

A distribution box ensures that electrical supply is distributed in the building, also known as a distribution board, panel board, breaker panel, or electric panel. It is the central electrical supply system of any building or property. As a component of an electrical system: it divides electrical power into subsidiary circuits and provides a protective fuse or circuit breaker for each circuit.

A distribution box houses all the contact breakers, earth leakage units, doorbells, and timers. The electrical power supply comes from the network to the building through the main feeding cable. The cable is connected to the distribution board and the power is distributed through the breakers in the secondary circuits (lights and plugs).

Components of a Distribution Box:

The basic structure and technical aspects of electrical distribution boards vary according to places and requirements. A typical electrical distribution box will include a bus bar, fuse links, switches, bypass equipment, and residual current detector (RSD.). At a broad level these components will aid in:

– Residential electrical installation

– The incoming supply circuit breaker or main switch

– Control and distribution board (consumer unit)

Surge protective devices

Earth resistance between the electrode and the point of zero potential.


Working with the wires and cables in an electrical system must be safe, and the distribution boards must ensure the following:

– The fuse should block overcurrent through the circuitry.

– There should be enough space for other wires, fixtures, and cables.

– Should not be prone to corrosion.

– Best-quality wiring should be used to ensure safety.

Main Functions 

Their main functions are to:

– Break up the power supply into sub-circuits depending on the purpose for it.

– Ensure that everyone and everything is safe against short circuits.

– Distribute power to different areas from the main power source.

Different types of distribution boards available serve specific distribution requirements, and some are also customizable.

Type of Distribution Boxes

Main Breaker Pane:

The most commonly used type is the main breaker panel and is important to have in any property as it:

1) Protects the circuits and controls the amperage capacity.

2) Protects the circuits from getting overheated.

3) Protects a power supply by shutting down (including the circuit breaker) in case of a short circuit.


Watch our video to understand the Types, Applications & Functions in Detail!


Main Lug Panel:

They are generally used as a distribution box during a main upstream breaker. Line wires are connected to these lugs, and the main lug panel can be used as a sub-panel when connected to a breaker from the main panel. The separate disconnection in the meter can be used during a fire or emergency. This will then serve as the main breaker and discontinue the power supply even before it enters the property/building.


Sub Panel:

Subpanels are suitable when multiple circuits are required within the same area. Subpanels are easy to install, safe, and efficient for residential homes. These are connected to the main panel through a circuit. They draw power from the main panel and adjust the distribution around an area or property. Being smaller, Sub Panels can distribute power to a specific part of a house or area on the property and work as satellite circuit breaker panels for the area. However, they do not have disconnection.


Transfer Switch:

A transfer switch (a type of subpanel) is used when a power-load needs to be shifted from one electrical source to another. For example – a normal supply to the generator and vice versa. It transfers the generator power to electrical power with the help of the breaker panel. Transfer switches are convenient to use as backup power generators where weather is unstable and unpredictable. In case of disruption of power supply, the transfer switch converts generator power to electrical power seamlessly through the breaker panel. There are two types of transfer switches:

1) Manual Transfer Switches: Used when one manually operates the switch to generate the electrical load to the backup power.

2) Automatic Transfer Switches: This is used to get temporary electrical power during a power supply disruption from a generator. It is seamless and easy to use, preferred by homeowners.


Panel Fuse Bank:

Serves as the load centre of a distribution system. It provides electrical safety protection of an over the current electrical circuit. A panel fuse bank is ideal for distributing electrical power from a solar panel. The power first gets stored on the solar panels and then goes directly to the fuse box before being distributed to the entire house.


Unitized Panel:

It is an exclusive one as this electronic meter displays the electrical parameters. Unitized panels are used in power centres to supply and deliver a low voltage of power from a medium-voltage line. These panels are used in industrial and commercial establishments


Industrial Lighting Panel:

They reduce the energy consumption in industrial establishments by programming the lights to turns-off during an idle period


Power Distribution Box

When we talk about distribution boxes we cannot ignore Power Distribution Boxes or Power Distribution Units (PDU) or a Distro. A distro safely distributes electricity from the power source to other devices in a circuit. It has one input and multiple outputs. That means several devices are connected to the distro rather than connecting directly to the power source. While ensuring safety, it makes distribution more efficient and convenient. The main advantage is its ability to reduce the chances of blown fuses or dangerous short-outs.

The shapes, sizes, and construction of power distribution boxes widely vary and can be customized. The possible variables are input and output voltages. Additionally, the number of inputs can also be adjusted, and manufactured with added safety features, such as MCBs and RCBs.

Power distribution boxes are useful as they eliminate the need to connect each output device directly to the power source. Therefore, there is no need to use more wires than what is necessary. This saves energy, streamlines the circuit, ensures efficiency, and controls power wastage. It creates a safer work zone for staff and visitors, as they have fewer physical wires to deal with. Wires can be a major tripping hazard as they get entangled with other things.


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