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

Protective conductor (PE)

Also known as: Protective earth, Equipment grounding conductor

German: Schutzleiter (PE)

In electrical installations and machinery, a protective conductor (PE) is a conductor provided for purposes of safety, in particular protection against electric shock, that connects exposed conductive parts to the protective earthing system so that a fault current trips the protective device. It is identified by the green-and-yellow color combination.

  • Automation components
  • Standards

In one sentence

The protective conductor (PE) connects exposed conductive parts to earth so a fault current trips the protective device; it is green and yellow.

Example

Before handover, the electrician tests the continuity of the protective bonding circuit from the PE terminal to every motor housing of the machine.

How it applies

  • Engineering: On machines, IEC 60204-1 requires a protective bonding circuit connecting all exposed conductive parts, with the PE terminal marked. Conductor sizes and connection methods follow the standard and the installation rules of the country.
  • Commissioning and maintenance: Continuity of the protective bonding circuit is verified before first use and after modifications; a missing PE connection is a direct Electrical hazard.
  • Documentation: Circuit diagrams mark PE clearly, and the installation instructions state how the machine is connected to the supply's protective earth. Warnings in the maintenance manual should require the PE to be reconnected after any component replacement.

Protective conductor vs. functional earth

The PE serves protection against electric shock. A functional earth (FE) serves the correct function of equipment, for example EMC shielding. They are not interchangeable, and FE must not replace PE.

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

Source: IEC 60204-1:2016+A1:2021, Safety of machinery — Electrical equipment of machines — Part 1: General requirements

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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