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Product overview

Overview of our high-voltage station arresters

Our portfolio consists of three types of surge arresters for specific applications:

3EL product family – Surge arresters with directly molded silicone rubber housing, Cage Design®
3EQ product family –
Surge arresters with silicone housing, composite hollow core design
3EP product family 
– Surge arresters with porcelain housing

Main features:

  • High mechanical stability for support applications and for use in regions with high seismic activity
  • Extremely reliable pressure relief for use in areas requiring special protection
  • Excellent pollution layer characteristics for use in coastal and desert regions or in areas with extreme air pollution
  • All three surge arrester product families feature a superior sealing system that reliably prevents moisture ingress
  • Decades of trouble-free service
  • Manufactured using only environmentally compatible materials


Our product families


3EL – Surge arresters with directly molded silicone rubber housing, Cage Design®

Siemens 3EL silicone rubber surge arresters with Cage Design® provide outstanding protection against overvoltages in networks up to 800 kV.


Siemens 3 EL Cage Design® surge arresters are ideally suited for the reliable protection of:
- Transformers
- Circuit breakers
- Generators
- Motors
- Capacitors
- Traction vehicles
- Bushings
- Switchgear
- Transmission lines

The cage, made of fiberglass-reinforced plastic (FRP) rods, provides a rigid, reinforced structure ensuring high mechanical strength. The silicone rubber housing is directly molded onto the metal oxide (MO) blocks and the surrounding cage made of FRP rods. This creates a reliable seal that prevents moisture ingress and partial discharges.


The MO resistors are not surrounded by a rigid mechanical coating, which is why no critical increases in pressure can occur in the surge arrester in the extremely rare event of an overload. The arc can escape directly through the soft silicone housing without damaging the mechanical structure. No internal parts are ejected in the process. The innovative Siemens Cage Design® is very secure.

The silicone rubber is highly hydrophobic and UV-resistant. This keeps any conductive moisture from forming on the surface, and dirt deposits are rendered harmless as a result of the hydrophobic transfer. Silicone is highly fire-retardant and self-extinguishing in the event of fire. These properties ensure the reliable, maintenance-free operation of 3EL surge arresters. They are also lightweight, allowing for easy transport and a variety of installation options. 3EL surge arresters are suitable for use as station or line surge arresters.


Technical data

Maximum values
Highest voltage of the system (kV)
  72.5 252 420 550
Maximum rated voltage (kV)
  60 198 360 444
Nominal discharge current (kA)
Thermal energy rating (kJ) / (kV) Charge transfer rating (C)        
10 4.5 1.0 X      
10 5.0 1.2   X    
10 6.0 1.6   X    
10 7.0 2.0     X  
20 9.0 2.4     X  
20 10.0 2.8       X
20 14.0 3.6       X
Rated short-circuit current (kA)
  20 65 65 65
High current impulse (kA)
  100 100 100 100
Specified short-term load SSL (kNm)
  0.5 1.2 4.0 10.0