Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Automation fundamentals, platforms and components

Overvoltage protection

Also known as: Surge protection, Surge protective device (SPD)

German: Überspannungsschutz

In electrical engineering, overvoltage protection is the set of measures and devices, such as surge protective devices (SPDs), that limit transient overvoltages caused by lightning or switching operations to values the equipment can withstand.

  • Automation components

In one sentence

Overvoltage protection limits transient overvoltages from lightning or switching to safe levels, typically using surge protective devices.

Example

Surge protective devices on the signal lines of a remote pumping station protect the PLC inputs after lightning strikes nearby.

How it applies

  • Engineering: Protection concepts use coordinated SPD types at the building entrance, distribution boards and equipment, plus protection on data and signal lines. Equipotential bonding is a prerequisite.
  • Maintenance: SPDs age with each surge; many have status indicators or remote signaling contacts and need periodic inspection.
  • Documentation: Installation documentation should show where SPDs are installed, their type and connection. Maintenance manuals should include inspection intervals and replacement criteria.
  • Operation: Remote signaling of SPD status lets operators replace worn protective devices before the next surge.

Overvoltage protection vs. overcurrent protection

Overcurrent protection (fuses, circuit breakers) disconnects when current is too high. Overvoltage protection limits voltage peaks, usually for microseconds, without interrupting supply. Both are needed and serve different purposes.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on IEC 61643 and IEC 62305 practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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