Metrolab Blog

High-graded overvoltage protection

The integrated overvoltage protection within the IQ SENSOR NET reduces the risk of default and increases the operational safety.

Overvoltage protection in general

To achieve sufficient protection against direct lightning strikes, the systems have to be equipped with a complete lightning protection system, e.g. according to IEC/EN 62305-1, 2, 3, 4. Lightning protection systems protecting against direct lightning strikes have to be implemented by skilled personnel on site. Lightning strikes are natural phenomena whose intensity and effects are not foreseeable. These effects are called surges.

Surges can be caused by the following incidents:

  1. Indirect effects of a lightning strike in the vicinity of the measuring system1)
  2. Switching processes in industrial low voltage systems (90 … 264 V AC)
  3. Lightning electromagnetic pulses (LEMP) due to lightning flashovers from cloud to cloud

Overvoltage protection of the IQ SENSOR NET

The lightning protection of the IQ SENSORNET protects against the indirect effects of a lightning strike. The IQ SENSORNET system is designed to intercept surges up to a certain level. This surge immunity – according to standard IEC/EN 61000-4-5 – was tested and certified under practice-oriented conditions. Without any additional installations, the IQ SENSORNET is suitable for use in Lightning Protection Zone 2 (LPZ 22)) according to IEC/EN 62305-4. The high-grade protection of the IQ SENSORNET can achieve a considerably lower failure probability of the measuring system but no protection guarantee.

Specifications of the IQ SENSOR NET

The specifications of the IQ SENSOR NET surpass the EU requirements for devices to be used in an industrial environment, defined in standard IEC/EN 61326-1 table 2. The details of these specifications can be requested under the following address: b  Techinfo.WTW[at]

1) hundreds of meters up to kilometers
2) LPZ = Lightning Protection Zone