Industrial secondary distribution box switch model

Common industrial secondary distribution switch models include Siemens 8DJH 24, ABB UniSec/UniGear series, and Eaton secondary unit substations, designed for medium-voltage indoor applications.

Siemens 8DJH 24 Switchgear

The 8DJH 24 is a factory-assembled, type-tested, 3-pole metal-enclosed switchgear for indoor installation, suitable for secondary distribution in industrial and renewable energy applications . Key features include:

• Voltage rating: up to 24 kV
• Insulation: Clean Air (natural gases), gas-insulated for compact design
• Service life: at least 40 years under normal conditions
• Maintenance: minimal, hermetically sealed enclosure protects against humidity, pollution, and small animals
• Flexibility: adaptable to new system conditions, optional earthquake resistance
• Switching devices: three-position switch-disconnectors with make-proof earthing switches

ABB Medium-Voltage Switchgear

ABB offers a range of medium-voltage switchgear for secondary distribution, including:

• UniSec: modular air-insulated switchgear up to 24 kV, suitable for indoor secondary distribution, with SF6-free variants (GSec Air) using dry air insulation
• UniGear ZS1/ZS2/ZS3.2: air-insulated switchgear for primary and secondary distribution, with withdrawable circuit breakers, voltage ratings from 24 kV to 40.5 kV
• Motor Control Centers (MCC): LeanGear ZS9 and UniGear Motor Control Center for motor, transformer, and capacitor bank switching up to 12 kV These models provide modularity, flexibility, and minimal service interruption, suitable for industrial environments.

Eaton Secondary Unit Substations

Eaton's secondary unit substations integrate primary high-voltage equipment, three-phase transformers, and secondary low-voltage switchboards . Features include:

• Design: close-coupled assembly to minimize secondary cable lengths
• Operation: can be configured as simple radial, primary selective radial, or secondary selective systems
• Reliability: bus tie breakers and main breakers allow rapid restoration in case of primary circuit failure
• Application: ideal for industrial facilities requiring continuous service and efficient secondary distribution

Design Considerations

When selecting a secondary distribution switch model, consider:

• Voltage and current ratings appropriate for the load
• Insulation type (air-insulated, gas-insulated, SF6-free)
• Indoor installation space and compactness
• Maintenance requirements and service life
• Flexibility for future expansion and system adaptation
• Safety features such as earthing switches, breaker interlocks, and fault protection These models are widely used in industrial plants, factories, and renewable energy facilities, providing reliable medium-voltage secondary distribution with options for modularity, low maintenance, and long-term operation.