ABB Unisec Medium Voltage Switchgear

UniSec Air is an air-insulated, SF6-free medium-voltage switchgear from ABB built for secondary power distribution up to 24 kV, 1250 A, and 25 kA, replacing sulfur hexafluoride with dry air as the insulating medium. This article covers the product’s ratings, service-continuity configurations, environmental profile, applicable standards, and typical deployment scenarios for utilities, industrial plants, and infrastructure projects across the Middle East and Gulf region including Egypt and Saudi Arabia, North Africa, the CIS, and Sub-Saharan Africa.

What is UniSec Air Switchgear?

UniSec Air is ABB’s SF6-free medium-voltage secondary distribution switchgear, designed as a direct evolution of the established UniSec platform, using dry air insulation instead of sulfur hexafluoride gas. The switchgear employs a compact GSec Air switch disconnector and disconnector, with all active parts segregated inside a low-volume tank of less than 25 liters. This design supports the global transition away from high-GWP insulating gases while maintaining reliable breaking and switching performance through a dedicated vacuum interrupter.

Why SF6-Free Switchgear Matters

Sulfur hexafluoride has historically been favored in switchgear for its excellent insulating properties and compact footprint, but SF6 carries a global warming potential of 24,300 times that of CO2, making it one of the most potent greenhouse gases in industrial use. Regulators, particularly in the European Union, are phasing out SF6 in medium-voltage equipment through binding legislation. UniSec Air is fully compliant with the EU F-gas regulation (EU) 2024/573, positioning buyers ahead of tightening environmental requirements without needing future retrofits.

The GSec Air switch disconnector and disconnector use a dry air insulation medium with a global warming potential of zero, combined with a dedicated vacuum interrupter for reliable breaking capacity. This eliminates risks tied to gas leaks or improper handling of hazardous insulating media, improving operator and environmental safety compared with SF6-filled equipment.

Product Scope and Ratings

UniSec Air is defined by the following rated parameters:

These ratings allow UniSec Air to serve both standard low-current distribution feeders and higher-duty applications requiring elevated breaking capacity, simply by selecting the withdrawable circuit breaker panel configuration.

Types and Configurations

Service Continuity (LSC) Options

UniSec Air offers multiple service continuity classifications — LSC2B, LSC2A, and LSC2 — tailored to different operational needs. These configurations determine how much of the switchgear can remain energized while maintenance or extension work is performed on an adjacent panel, directly affecting uptime during servicing activities.

Frontal Withdrawable Circuit Breaker Panel (LSC2B)

The LSC2B frontal withdrawable circuit breaker panel is the configuration that unlocks the switchgear’s highest current and short-circuit ratings, raising rated current to up to 1250 A and short-time withstand current to up to 25 kA, alongside an internal arc classification of up to IAC A FLR 25 kA. This variant suits applications where higher fault-current withstand and load capacity are required.

Compatibility with UniSec

A key structural advantage is the compatibility between UniSec Air and the original UniSec platform. This allows operators with an existing UniSec installed base to expand or retrofit sections of their network with SF6-free panels without redesigning the entire switchgear lineup.

Selection Criteria

When specifying UniSec Air for a project, buyers and engineers should evaluate:

• Required rated current — whether the standard rating up to 630 A is sufficient, or whether the higher 1250 A rating via LSC2B is needed.
• Fault-current withstand needs — projects with higher prospective fault levels should confirm whether the 20 kA or 25 kA short-time withstand rating matches network requirements.
• Internal arc safety requirements — sites with strict personnel-protection mandates should verify the applicable IAC classification and whether gas exhaust needs to be routed inside or outside the switchroom.
• Service continuity class — LSC2B, LSC2A, or LSC2 selection based on how critical minimal-interruption maintenance is for the installation.
• Regulatory compliance timeline — projects in jurisdictions moving toward F-gas restrictions benefit from specifying SF6-free equipment now rather than facing future retrofit costs.
• Installation footprint and access — easy frontal and lateral access to MV cable connections simplifies installation, operation, and maintenance in constrained switchrooms.
• Integration with existing assets — for brownfield projects, compatibility with the legacy UniSec range reduces engineering complexity.

Safety and Interlocking Features

UniSec Air incorporates a wide range of mechanical and electrical interlocks designed to enhance operator safety. Internal arc classification is paired with a gas exhaust system that can be configured according to the specific application, directing pressure relief either inside or outside the switchroom. Combined with the low-volume, segregated GSec Air tank design, these features reduce fault-related hazards for personnel working near the switchgear.

Environmental and Recycling Profile

UniSec Air is manufactured under quality and environmental management systems, with ABB complying with ISO 14001 standards. The switch disconnector and disconnector actuator is made of fully recyclable steel, and the product’s overall material breakdown for the SDC 500 mm unit demonstrates strong recyclability:

This recycling profile is based on the SDC 500 mm functional unit, giving procurement and sustainability teams a documented basis for end-of-life planning and environmental reporting.

Digital Tools and Documentation

ABB provides two digital tools to support UniSec Air specification and design work. BiMagic Designer is a web-browser-based application developed to digitalize the configuration activity of consultants and designers, allowing users to select switchgear characteristics, drag-and-drop typical units, and automatically generate project previews for export and collaboration. UniSec Pro is a tender and switchgear design tool that configures both UniSec Air and UniSec within the same interface, offering preconfigured standard solutions and complete technical/commercial documentation including editable project drawings.

Applications

UniSec Air is intended for secondary medium-voltage distribution, serving as the interface between incoming MV supply and downstream transformers or feeders in utility substations, industrial plants, commercial buildings, and infrastructure facilities. Its SF6-free design and compatibility with the legacy UniSec platform make it particularly relevant for utilities and EPC contractors that need to modernize distribution networks while meeting tightening environmental regulations. Buyers across the Middle East and Gulf region including Egypt and Saudi Arabia, North Africa, the CIS, and Sub-Saharan Africa can specify UniSec Air for new distribution projects or as a drop-in SF6-free upgrade path alongside existing UniSec installed bases.

Standards and Compliance

UniSec Air is developed in accordance with the requirements established by IEC 62271-200, the standard governing AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV. Manufacturing is also carried out under quality and environmental management systems compliant with ISO 14001. The product’s SF6-free design further ensures alignment with the EU F-gas regulation (EU) 2024/573, giving specifiers confidence in long-term regulatory compliance.

Related guides

See also our guides on gas-insulated switchgear, ring main units and metal-clad switchgear.