Protecting Against Transient Surge Conditions

Surge Protective Devices (SPDs) are essential safeguards designed to shield against transient surge conditions. These surges, often caused by lightning strikes or utility power anomalies, can reach extremely high voltages, leading to immediate or intermittent equipment failure. Surprisingly, such external events account for only 20% of surge activity.

Internal Surge Causes

The majority—80%—of surge incidents are generated internally. While these surges may be of lower magnitude than lightning strikes, their frequent occurrence and continuous exposure can gradually degrade sensitive electronic equipment within a facility.

  • Comprehensive Protection : Shields against both external lightning strikes and internal power anomalies.
  • Enhanced Equipment Longevity : Prevents damage that can occur from continuous exposure to internal surges.
  • Reliable Performance : Ensures uninterrupted operation of sensitive electronics and equipment.

Surge Protective Devices SPD Class I

High Discharge Capacity

OVR Type 1 and Type 1+2 SPDs are designed to safely discharge high-current surges without damaging the installation. These devices are capable of withstanding impulse currents with a 10/350 µs waveform, simulating direct lightning strikes. Type 1 and Type 1+2 SPDs are typically installed at the entrance point of installations, such as main distribution boards, providing comprehensive protection for the entire setup.

  • High Impulse Current Handling : Capable of handling impulse currents of 25kA per pole (10/350 µs waveform), meeting stringent overvoltage surge protection standards.
  • Optimized Protection Level : Features electronic ignition for early arc creation, reducing the protection level to an optimal 2.5kV.
  • Arc Extinguishing Capability : Includes a dedicated arc chamber to safely extinguish electrical arcs following discharge, enabling handling of short circuits up to 50kA without additional backup protection.
  • Follow Current (If) : Offers three types of follow current capacities: 50kA, 15kA, and 7kA.

Surge Protective Devices SPD Class II 

Good Protection Level

OVR Type 2 and Type 2+3 SPDs are designed to protect electrical installations and sensitive equipment against indirect surges, providing a low protection level (Up). These devices safely discharge currents with an 8/20 µs waveform, making them effective for mitigating transient surges.

  • Versatile Application : Available in specific multi-pole versions suitable for all distribution systems.
  • Low Protection Level (Up) : Maximum protection level Up is 1.25 kV, ensuring suitable protection for all terminal equipment, including sensitive devices.
  • Safety Reserve System : OVR Type 2 devices feature a safety reserve system for extended equipment protection.
  • Maximum Discharge Current (Imax) : Available in ratings of 20kA, 40kA, and 80kA.
  • Maximum Protection Level (Up) : Options include 1kV, 1.4kV, and 1.5kV, providing varied levels of protection.
  • Maximum Continuous Operating Voltage (Uc) : Available in AC/DC ratings of 75V, 150V, 275V, 350V, 440V, 600V, and 760V, ensuring compatibility with different electrical systems.

Surge Protective Devices (SPD) Class III

Low Protection Level Voltage Value

OVR Type 3 surge protective devices are designed to be installed as close as possible to sensitive equipment to provide protection. Tested with a 1,2/50 – 8/20 current combination wave generator, they ensure a very low protection level voltage value.

  • Suitable for Sensitive Equipment : Provides an extremely low level of protection voltage value suitable for all sensitive terminal equipment.
  • High Maximum Discharge Current (Imax) : Offers a maximum discharge current (Imax) of 10kA, ensuring robust protection against transient surges.
  • Dual Mode Protection : Provides both common and differential mode protection for comprehensive coverage.
  • Maximum Discharge Current (Imax) : Rated at 10kA, offering substantial surge handling capability.
  • Maximum Protection Level (Up): Up to 900V, indicating the maximum voltage level that the SPD can protect against.
  • Maximum Continuous Operating Voltage (Uc) : Available in AC ratings of 275V and 440V, suitable for different electrical systems.