Schneider Premset Switchgear

Premset switchgear (marketed by Schneider Electric under the “PremSet” name within its Set Series family) is a compact, modular medium-voltage switchgear line built around a Shielded Solid Insulation System (SSIS), in which every live part of the main circuit is encapsulated in an earthed epoxy or EPDM shield so the assembly is classified as “accidentally touchable.” This article covers the product’s design philosophy, technical ratings, functional variants, selection criteria, applications, and governing standards for engineering and procurement teams. It is particularly relevant for buyers and EPC contractors sourcing MV secondary distribution equipment across the Middle East and Gulf region including Egypt and Saudi Arabia, North Africa, CIS countries, and Sub-Saharan Africa, where compact footprint, tropicalized ratings, and long service life are recurring procurement priorities.

What Is Premset Switchgear?

Premset is a 17.5 kV-class compact modular vacuum switchgear system positioned by Schneider Electric within its broader Set Series portfolio of MV and LV switchboards. The defining feature is the SSIS design: rather than relying solely on air or gas insulation with exposed conductors inside grounded enclosures, Premset embeds the switching, disconnecting, and earthing functions in solid, shielded insulation, reducing the probability of internal arc faults and enabling a smaller equipment footprint.

The system was previously known under the same “Premset” name and has been renamed “PremSet” as part of Schneider Electric’s Set Series naming consistency initiative, alongside other renamed products such as ComPact, MasterPact, TransferPact, and FuPact.

Core Technology: Shielded Solid Insulation System (SSIS)

The SSIS concept is the technical backbone of the Premset range. The entire main circuit — switch-disconnectors, earthing switches, current and voltage sensors, and metering units — is insulated with solid epoxy or EPDM material whose outer surface is maintained at earth potential throughout. Because the electric field does not propagate into the surrounding air, the switchgear body itself becomes safe to approach or touch under normal operating conditions.

This design is stated by the manufacturer to align with the PA (accidentally touchable) classification defined in IEC 62271-201, the standard covering AC metal-enclosed and solid-insulation switchgear assemblies for rated voltages above 1 kV up to and including 52 kV.

Key benefits attributed to SSIS include: – Reduced sensitivity to harsh environments such as humidity, dust, and pollution – Lower risk of phase-to-phase faults due to solid insulation between phases – Extended service life expectancy compared to conventional air-insulated designs

SSIS is applied not only to the main switching device but also to auxiliary functions, including the M06S compact metering unit, current transformers, and voltage transformers.

The “3-in-1” Integrated Core Unit

Rather than using separate devices for breaking, disconnecting, and earthing, Premset integrates all three functions into a single core unit with only three defined positions:

1. Closed — circuit connected
2. Open and disconnected — circuit isolated
3. Earthed — downstream conductors grounded

This single-line arrangement combines a switch-disconnector using vacuum interrupters with an earthing switch sealed in a tank at atmospheric air pressure, allowing MV cables to be earthed directly through the earthing switch without requiring any other device. The series arrangement of the two devices provides double isolation between busbars and cables.

Operators benefit from an intuitive mimic diagram with two clear position indicators, designed in accordance with IEC 62271-102, the standard governing high-voltage alternating-current disconnectors and earthing switches. All interlocks between the switching, disconnecting, and earthing functions are built-in as standard, positively driven, and keyless, applying equally to circuit breaker and load break switch variants.

Integrated Cable Test Feature

For maintenance teams, Premset includes a front-accessible cable test function implemented through dedicated earth rods, eliminating the need to enter the cable box, operate main switches, or dismantle cable terminations before testing. This cable test device is stated to meet the requirements of IEC 62271-200, the standard for AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV.

Technical Ratings and Specifications

Premset is offered across three voltage classes, with insulation levels and short-circuit performance summarized below.

Additional functional and environmental ratings:

For marine-rated protection and control chains, Premset Marine supports short-circuit performance up to 25 kA for 1 second.

Design and Connection Features

Premset’s flexibility is built around a common architecture used across every configuration, which simplifies customization and installation:

• Universal flat power connection — a patented single connection interface allowing cables to be routed from the front, rear, bottom, or top, while maintaining earth shield continuity.
• Embedded sensors — integrated current and voltage sensors built around the core function, avoiding the need for extra or larger cubicles.
• Standardized cabling height — all cable connections positioned at 700 mm to simplify installation across the range.
• Multiple cable box dimensions — a range of sizes to suit different substation rooms and cabling arrangements, with an embedded voltage option.

These design choices are intended to reduce both installation time and total lifecycle footprint, which is a common evaluation criterion for utilities and industrial buyers standardizing on a single switchgear platform across multiple substations.

Digital and Smart Grid Capabilities

Premset architecture supports distributed intelligence through intelligent electronic devices (IEDs) that communicate over a standard protocol with plug-and-play configuration. Supported functions include:

• Feeder automation with built-in local intelligence and communication
• Load management through integrated smart metering
• Asset management via advanced switchgear and transformer monitoring
• Automatic transfer system (ATS) functionality to reduce power supply interruption

Connected components in the ecosystem include fault passage indicators, protection relays, energy quality monitoring devices, switch controllers, and substation monitoring devices, linked via radio, 2G/3G, or Ethernet communication networks.

Applications

Premset switchgear is designed for use across a broad range of MV secondary distribution scenarios, including:

Buildings and industry – MV/MV and MV/LV consumer substations (direct, double feeder, loop, radial connections) – MV/LV consumer substations with MV backup – MV private networks

Distribution networks – MV/MV switching substations – MV/LV distribution substations and ring main units – MV distributed generation

Marine applications Premset holds DNV-GL type approval certification for marine use, offering an enhanced protective environment, improved reliability, and a smaller footprint compared to conventional shipboard switchgear. The marine variant retains the electrical and dimensional characteristics of the standard range, adapted with features such as PM partition-class compartmentalization, front access, IP41 or IP32 enclosure ratings (IP67 for HV parts), and optional thermal diagnostics. A dedicated tunnel above the cubicle is designed to absorb gases from internal arcing events specific to onboard installations.

Environmental and Long-Term Reliability Considerations

Premset is offered as an SF6-free design, positioning the range for markets and end users seeking to reduce dependency on SF6 gas insulation in MV switchgear. Combined with the SSIS insulation approach and reduced number of operating steps (a single motion each for opening/disconnecting and for earthing), the range is positioned to lower total cost of ownership through extended service life and simplified maintenance intervals.

Standards and Compliance

Premset switchgear is engineered against multiple IEC standards relevant to MV switchgear procurement:

• IEC 62271-200 — governing AC metal-enclosed switchgear and controlgear; referenced specifically for the integrated cable test device.
• IEC 62271-201 — governing AC metal-enclosed and solid-insulation switchgear assemblies; referenced for the PA (accidentally touchable) classification of the SSIS design.
• IEC 62271-102 — governing high-voltage AC disconnectors and earthing switches; referenced for the mimic diagram and position indication design.
• IEC 60068-2-6 — governing vibration testing procedures; referenced for the stated vibration withstand values.

Buyers specifying MV switchgear for regulated utility or industrial projects should request certification documentation confirming compliance with the applicable standard for the specific function (switch-disconnector, circuit breaker, or metering unit) being procured.

Selection Criteria for Buyers

When evaluating Premset switchgear against alternative MV switchgear platforms, procurement and engineering teams should assess:

1. Voltage class required — 7.2 kV, 12 kV, or 17.5 kV, matched to network nominal voltage and future expansion plans.
2. Short-circuit and current ratings — confirm the 25 kA/3 s short-time withstand and busbar/circuit-breaker current ratings meet system fault-level and load requirements.
3. Insulation philosophy — whether a solid, shielded insulation approach (as opposed to gas- or air-insulated designs) aligns with site environmental conditions (humidity, dust, pollution exposure).
4. Environmental rating needs — ambient temperature range and humidity tolerance, particularly relevant for installations in high-humidity or high-temperature GEO markets.
5. Digital integration requirements — whether feeder automation, remote monitoring, or automatic transfer system functionality is needed for the substation.
6. Application type — standard MV/LV distribution substation, ring main unit, distributed generation interface, or marine/offshore installation requiring DNV-GL type-approved equipment.
7. Cable connection layout — front, rear, bottom, or top cabling access based on civil works and substation room layout.