Siemens NXAIR Switchgear

NXAIR switchgear is Siemens’ air-insulated, metal-enclosed, factory-assembled medium-voltage switchgear platform designed for primary distribution applications up to 17.5 kV and up to 40 kA short-circuit rating. This article covers the NXAIR design and classification, its main components, technical characteristics, typical applications, and the governing IEC standard, giving procurement and engineering teams the information needed to specify the product correctly. NXAIR is widely deployed by utilities and industrial end users across the Middle East and Gulf region (including Egypt and Saudi Arabia), North Africa, the CIS, and Sub-Saharan Africa, where robust air-insulated switchgear is preferred for primary substations, industrial plants, and offshore installations.

What Is NXAIR Switchgear?

NXAIR is a global platform of circuit-breaker switchgear that uses ordinary air as the insulating medium instead of SF6 or other F-gases, combined with maintenance-free vacuum interrupters for switching duty. Because air is the insulation medium, no gas handling, gas monitoring, or pressure supervision is required on site, simplifying installation and long-term operation. The platform concept means the same design principles are applied worldwide, with centrally controlled development and locally manufactured components adapted to regional standards. More than 610,000 air-insulated Siemens switchgear panels of this family are reported in operation worldwide, reflecting a long track record in the field.

Design and Classification

NXAIR is factory-assembled, metal-enclosed, and type-tested switchgear for indoor installation, classified according to IEC 62271-200. The switchgear is built around a modular panel with distinct compartments — busbar, switching-device, connection, low-voltage, and a withdrawable circuit-breaker section — each separated by pressure-resistant partitions for enhanced operator safety.

Key classification parameters include:

• Loss of service continuity category: LSC 2B, meaning the busbar, connection, and switching-device compartments are separately partitioned.
• Partition class: PM, i.e., metal-clad in pressure-resistant design.
• Internal arc classification: IAC A FLR, covering front, lateral, and rear accessibility, valid for all rated short-circuit currents with an arc duration of 1 second.
• Degree of protection: Standard IP3XD, with higher degrees of protection available as an option, up to a maximum of IP51.
• Internal arc confinement: The switchgear confines an internal arc to the respective compartment for short-circuit currents up to 31.5 kA.

All high-voltage operations require the door to be closed and interlocked, and the design incorporates earthed shutters, a logical mechanical interlocking system, and unambiguous position indicators on the high-voltage door for safe, error-free operation.

Main Components

The NXAIR panel integrates several key components:

• Vacuum circuit-breaker — withdrawable, maintenance-free switching device using Siemens’ SION circuit-breaker series, contributing to the compact panel footprint.
• Switch-disconnector/fuse combination and vacuum contactor options for feeder protection variants.
• Block-type current transformers — standardized units used across the platform.
• Voltage transformers, including a withdrawable option.
• Make-proof earthing switch, type-tested together with the main switching devices in the panel.
• Low-voltage compartment — removable, with plug-in wiring for flexibility.
• Optical arc detection systems and the SIQuench arc quenching device, available to further reduce the consequences of an internal arc event.
• Pressure relief duct system for directing arc energy safely away from the operator area.

Cable testing can be performed without isolating the busbar, and functions such as isolating-distance establishment and feeder/busbar earthing can be fully controlled remotely, supporting safer and faster switching operations.

Technical Data Summary

Applications

NXAIR circuit-breaker switchgear is deployed at transformer and switching substations, primarily at the primary distribution level. Typical sectors include public power supply — power supply companies, energy producers, and system operators — as well as a broad range of industrial and offshore applications such as the automobile industry, traction power supply, mining, chemical processing, diesel power plants, electrochemical plants, emergency power installations, textiles, paper and food processing, iron and steel works, oil and gas, offshore platforms, petrochemical plants, pipeline installations, data centers, shipbuilding, cement production, and rolling mills.

NXAIR has also been type-approved for maritime and offshore use by classification societies Lloyd’s Register and DNV, confirming its suitability for shipboard and platform installations.

Standards, Sustainability, and Certification

NXAIR switchgear is manufactured and sold under a certified management system in accordance with ISO 9001, ISO 14001, and BS OHSAS 18001. Classification and type testing follow IEC 62271-200 for metal-enclosed, indoor switchgear.

From a sustainability standpoint, NXAIR relies on natural air as its insulating medium and vacuum interrupters for switching, and it is free of asbestos, mercury, SF6, and other F-gases. Siemens performs Life Cycle Assessments and provides Environmental Product Declarations for reference installations, following the ISO 14040/14044 series of standards. The maintenance-free vacuum circuit-breakers, homogeneous and fully recyclable materials, and a service life beyond 30 years contribute to a favorable lifecycle energy balance for owners.

Related guides

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