Distribution box high voltage box low voltage box

Main Distribution Boxes manage low-voltage power distribution, High Voltage Boxes handle high-voltage energy conversion and distribution, and Low Voltage Boxes safely distribute electricity to end-user circuits.

Main Distribution Box (MDB)

A Main Distribution Box is a central low-voltage distribution board that receives electrical power from one or more sources and distributes it to branch circuits within a facility. It typically houses circuit breakers for each branch to prevent overloads and short circuits, and its design allows for future expansion without major reconfiguration. MDBs are commonly used in industrial plants, high-rise buildings, data centers, and power utilities to centralize monitoring, control, and protection of electrical circuits .

Low Voltage Box (LV Box)

A Low Voltage Box or LV distribution board is designed to safely distribute low-voltage electricity (typically 400V/690V) to multiple outgoing circuits. It contains protective devices such as MCBs, RCDs, RCBOs, fuses, busbars, and surge protection devices. LV boxes are used in residential, commercial, and industrial settings to ensure safe and organized power delivery to lighting, motors, and appliances. They also provide isolation, earthing, and surge protection for connected equipment .

High Voltage Box (HV Box)

A High Voltage Box is used to manage and distribute high-voltage energy, often in the range of 300V to 900V in automotive or industrial applications. It integrates components like an Onboard Charger (OBC), DC/DC converter, and Power Distribution Unit (PDU). The OBC converts AC from the grid to DC for high-voltage batteries, while the DC/DC converter manages energy flow between high-voltage and low-voltage systems. HV boxes also include safety features such as fused outlets and interlocks to monitor connector integrity .

Key Differences

• Voltage Level: HV boxes handle high-voltage systems, while MDBs and LV boxes operate at low voltage.
• Function: HV boxes focus on energy conversion and distribution for high-voltage networks; MDBs manage overall low-voltage distribution; LV boxes distribute power to end-user circuits.
• Components: HV boxes include OBCs, DC/DC converters, and PDUs; MDBs and LV boxes include circuit breakers, busbars, and protective devices.
• Applications: HV boxes are used in electric vehicles, substations, and industrial high-voltage systems; MDBs and LV boxes are used in buildings, factories, and utilities . Understanding these distinctions ensures proper selection, installation, and safety in electrical systems, whether for residential, commercial, or industrial applications.