Siemens 8DJH Gas Insulated Switchgear

8DJH gas insulated switchgear is a factory-assembled, type-tested, three-pole, metal-enclosed single-busbar medium-voltage switchgear from Siemens, designed for indoor secondary distribution systems and insulated with SF6 gas inside hermetically sealed, welded stainless-steel vessels. This article explains the 8DJH product family — its panel types, electrical ratings, construction, applications, and governing standards — so procurement and engineering teams can specify the correct configuration for a given project. Buyers across the Middle East and Gulf region including Egypt and Saudi Arabia, North Africa, the CIS states, and Sub-Saharan Africa evaluate 8DJH switchgear specifically for its compact footprint, environmental sealing, and minimal maintenance burden in harsh or space-constrained substations.

What Is 8DJH Gas Insulated Switchgear?

8DJH is Siemens’ gas-insulated medium-voltage switchgear platform for secondary distribution systems, built around a single busbar architecture. The primary circuit — busbars, switching devices, and cable terminations — is housed inside welded stainless-steel vessels filled with SF6 insulating gas, which is described as non-toxic, odorless, colorless, non-inflammable, chemically neutral, heavier than air, and electronegative (a high-quality insulator). This gas has a Global Warming Potential (GWP) of 22,800.

Because the primary circuit is hermetically sealed against the environment, 8DJH switchgear is positioned as insensitive to aggressive ambient conditions such as saline air, humidity, dust, and condensation, and tight against ingress of dust, pollution, small animals, and moisture. This makes it a preferred choice for coastal, desert, and industrial installations where air-insulated equipment would face accelerated degradation.

Panel Types and Variants

Siemens offers 8DJH in several configurations to match substation layout and functional requirements:

• Individual circuit-breaker panel (500 mm) — a single-function panel equipped with a vacuum circuit-breaker and three-position disconnector for protection duties.
• 8DJH Standard panel blocks — modular ring-main and transformer feeder combinations for typical secondary substations.
• 8DJH Compact — a reduced-footprint variant intended for space-constrained rooms and prefabricated substations, including designs suitable for installation without a control aisle.
• RRT block — a combined ring-main/transformer feeder block used in common distribution layouts.
• Air-insulated billing metering panels — used alongside the gas-insulated panels where separate air-insulated metering compartments are required.

Panels and panel blocks can be lined up and extended on site without any SF6 gas work, and the low-voltage compartment is available in multiple overall heights with plug-in wiring to simplify commissioning and future extension.

Electrical Ratings and Technical Data

The table below summarizes the maximum electrical values published for 8DJH across its available rated-voltage classes.

Panel width depends on feeder function, with options of 310 mm, 430 mm, or 500 mm. Panel depth is 775 mm without the pressure relief duct and 890 mm with it. Panel height, excluding the low-voltage compartment and pressure relief duct, is available in 1040 mm, 1200 mm, 1400 mm, or 1700 mm options.

SF6 Gas System Parameters

The switchgear vessel is filled with SF6 gas at a rated filling level of 150 kPa (absolute, at 20 °C) with a design pressure of 180 kPa and a design gas temperature of 80 °C. The bursting disc operates at a pressure of at least 300 kPa, with bursting pressure of at least 550 kPa. The system is designed for a gas leakage rate below 0.1% per year, supporting the sealed-for-life claim.

Vacuum Circuit-Breaker and Switching Devices

Protection feeders use a vacuum circuit-breaker combined with a three-position disconnector for disconnecting and earthing functions. The circuit-breaker is maintenance-free under normal ambient conditions, requires no relubrication or readjustment, is rated for up to 10,000 operating cycles, and is vacuum-tight for life. Ring-main and switching functions are served by the three-position switch-disconnector, which provides load-break switching plus make-proof earthing.

Selection Criteria

When specifying 8DJH gas insulated switchgear, buyers should evaluate:

• Rated voltage class — select from the 7.2 kV, 12 kV, 15 kV, 17.5 kV, or 24 kV classes based on network voltage and required insulation margin.
• Short-circuit withstand requirement — match the network’s prospective fault level against the rated peak, making, and short-time withstand current figures for the chosen voltage class.
• Feeder mix — ring-main, circuit-breaker, and transformer feeders each have different rated normal current allocations (200 A / 250 A / 400 A / 630 A depending on function and design options).
• Panel type — Standard, Compact, RRT block, or individual circuit-breaker panel depending on footprint and layout constraints.
• Internal arc classification (IAC) needs — where personnel safety in the event of an internal fault is a priority, verify the IAC option and its test parameters.
• Installation arrangement — wall-standing or free-standing, and whether pressure relief is directed downward, to the rear, or upward.
• Regional approvals — for CIS markets, confirm GOST R certification applicability.

Applications

8DJH switchgear is used at the secondary distribution level in public and industrial energy systems, including local ring-main units, customer transfer substations, and switching substations of power supply and public utilities; wind power, solar, and hydroelectric plants; water and sewage treatment plants; airports, railway stations, and underground railway stations; open-cast mining facilities; and high-rise buildings.

Safety, Personnel Protection, and Service Life

All high-voltage parts of the primary circuit carry a standard degree of protection of IP65, and the overall switchgear enclosure provides at least IP2X, per IEC 60529 and VDE 0470-1. Feeder earthing is achieved through make-proof earthing switches, and HV HRC fuses and cable sealing ends are accessible only when outgoing feeders are earthed, reducing the risk of contact with live parts during maintenance.

Where the optional internal arc classification is specified, 8DJH panels are tested for resistance to internal faults with an arc test current of up to 21 kA for a test duration of 1 second. The IAC designation covers accessibility types — front (F), lateral (L), and rear (R) — for wall-standing and free-standing arrangements, and the Compact design also supports use in prefabricated substations without a control aisle, tested to IEC 62271-202.

Under normal operating conditions, the expected service life of 8DJH gas-insulated switchgear is at least 35 years, and probably 40 to 50 years, taking the tightness of the hermetically welded switchgear vessel into account. Service life limitations are governed by the operating-cycle endurance classes of the installed switching devices: circuit-breakers per the endurance class in IEC 62271-100, three-position disconnectors and earthing switches per IEC 62271-102, and three-position switch-disconnectors and earthing switches per IEC 62271-103.

Siemens states that more than 500,000 switchgear panels of this type of design are in operation worldwide, supporting a track record of field reliability.

Standards and Regional Approvals

8DJH switchgear is classified according to IEC/EN 62271-200 / VDE 0671-200. The sealed-for-life design (sealed pressure system) also follows IEC 62271-200. General maintenance-free operation under normal ambient conditions is referenced to IEC 62271-1 and VDE 0671-1. Interlocking systems comply with IEC 62271-200 and VDE 0671-200. Cable connections use the outside-cone plug-in system per DIN EN 50181. Metal partitioning corresponds to the “metal-clad” concept per the former standard IEC 60298.

The manufacturing system is certified according to ISO 9001, ISO 14001, and BS OHSAS 18001, with quality assurance additionally referenced to DIN EN ISO 9001.

For CIS-region projects, 8DJH holds national GOST R certification in Russia, approved for application at voltage levels of 6 kV, 10 kV, and 20 kV, with validity extending to Russia, Belarus, Kazakhstan, and Ukraine.<!– 🔴 iddia: By certification in the system GOST R in Russia, 8DJH is approved for application at the voltage levels 6 kV, 10 kV and 20 kV. The

Related guides

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