Medium-voltage surge arrester 3EK8 séries

class Ifor electrical installationsfor electrical networks

Overview Medium-voltage surge arresters protect electrical equipment from overvoltages caused by lightning, switching operations and other transient events. Siemens Energy offers a portfolio for distribution networks and critical equipment up to 72.5 kV, with polymer (silicone) and porcelain housing options to meet different environmental and performance requirements.

Key functions and features

• Wide voltage range: suitable for applications up to 72.5 kV.
• High energy absorption: protects sensitive and high-demand equipment to maintain operational reliability.
• Advanced housing materials: silicone rubber (polymer) and porcelain options for pollution and mechanical resistance.
• Reliable pressure relief: controlled arc venting without ejection of internal parts.
• Maintenance-free operation: hydrophobic HTV silicone reduces moisture-related contamination and tracking.
• Standards compliance: designed to meet IEC 60099-4 requirements.

Product portfolio and series highlights

• 3EK distribution-class arresters — for protection of transformers, circuit breakers, switchgear and distribution lines; available in multiple designs.
• 3EK7 Cage Design™ — FRP cage with silicone molded on MO blocks for superior sealing and partial-discharge prevention.
• 3EK8 wrap design — silicone molded on MO blocks with fiberglass wrap allowing safe arc escape and excellent moisture resistance.
• 3EJ family — high-energy absorption arresters for generators, motors, arc furnaces, dry-type transformers, airfield lighting, cable sheathing and converters.
• 3EH4 plug-in arresters — plug-and-socket units compliant with EN 50180 / EN 50181 for up to 52.5 kV, designed for high power handling and long service life.
• 3EP-G porcelain arresters — porcelain housings with directional pressure relief and short-circuit current capability up to 300 kA for demanding generator and motor protection.

Comparison table (feature — description) Voltage range — Up to 72.5 kV
Housing materials — Silicone rubber (polymer) and porcelain
Mechanical reinforcement — FRP cages or fiberglass wraps for structural integrity
Pressure relief — Controlled venting to avoid ejection of internal parts
Hydrophobicity — HTV silicone prevents conductive moisture films and reduces contamination transfer
Fire safety — Silicone is fire-retardant and self-extinguishing
Short-circuit capability — Up to 300 kA (3EP-G porcelain types)

Applications

• Distribution networks: protection for transformers, circuit breakers and distribution lines.
• Industrial facilities: safeguarding sensitive electrical equipment in manufacturing and processing plants.
• Renewable energy systems: protection for wind, solar and hybrid installations.
• Utilities: enhancing grid reliability and reducing outage risk from surge events.

Technical highlights and benefits

• Polymer (silicone) housings: hydrophobicity, lighter weight and improved pollution performance compared with porcelain.
• Porcelain housings: high mechanical robustness and superior short-circuit current capability where required.
• Innovative pressure-relief designs: improve personnel and equipment safety by directing arc energy away from mounting structures.
• Long service life and low failure rates when installed and operated per specifications.

Technical specifications

• Voltage rating: up to 72.5 kV (portfolio range).
• Housing materials: HTV silicone (polymer) and porcelain options.
• Hydrophobic silicone: high-temperature vulcanized silicone for moisture and contamination prevention.
• Mechanical reinforcement: FRP cages or fiberglass wraps (e.g. 3EK Cage Design™, 3EK wrap design).
• Energy absorption: available configurations from distribution-class to high-energy (3EJ family).
• Short-circuit capability (porcelain types): up to 300 kA for 3EP-G variants.
• Standards: IEC 60099-4; plug-in types compliant with EN 50180 / EN 50181 (3EH4).