IEC 61643-12-2020 PDF

Full title and description

Low-voltage surge protective devices - Part 12: Surge protective devices connected to low-voltage power systems - Selection and application principles. This part of IEC 61643 describes principles for the selection, operation, location and coordination of surge protective devices (SPDs) containing at least one non-linear component, intended to limit surge voltages and divert surge currents on 50/60 Hz AC power circuits and on equipment rated up to 1 000 V RMS.

Abstract

This standard (IEC 61643-12:2020, 3rd edition) provides guidance and requirements for selecting and applying SPDs in low-voltage power systems. It addresses where SPDs should be installed, how they should be coordinated with system insulation levels and other protective devices, what performance characteristics to consider (including measured limiting voltage and current-handling capability), and practical aspects such as disconnecting devices and failure modes. It complements product test standards by focusing on application and system-level selection.

General information

• Status: Published / Current
• Publication date: 7 May 2020
• Publisher: International Electrotechnical Commission (IEC)
• ICS / categories: 29.240.10 (Electromagnetic compatibility; surge arresters / SPDs)
• Edition / version: 3.0 (third edition)
• Number of pages: 433

Scope

IEC 61643-12:2020 applies to SPDs intended for connection to low-voltage (50/60 Hz) AC power circuits and to equipment with rated voltages up to 1 000 V RMS. The standard covers principles for determining the need for protection, selection criteria, mounting/location and coordination with other protective measures, characteristics to be specified by manufacturers and users, and measures to limit consequences of SPD failure. It does not replace product test standards and does not cover surge-protection components (SPC) that are integrated inside equipment. References and cross‑links to related installation and lightning-protection standards (for example IEC 60364 and IEC 62305-4) are included.

Key topics and requirements

• Principles for need assessment: determining when SPDs are required based on equipment sensitivity, service continuity and environmental exposure.
• Selection parameters: system voltage, nominal discharge current and lightning current handling, measured limiting voltage, nominal voltage protection level, response time and follow‑current characteristics.
• Location and coordination: preferred installation points (e.g., service entrance, distribution boards, local equipment), coordination with overcurrent protection and insulation levels to achieve the intended protection level.
• Disconnecting and replacement provisions: guidance on devices and arrangements that allow safe SPD disconnection and replacement after end of life or failure.
• Failure modes and consequences: assessment of possible SPD failures and measures to reduce risk to personnel and equipment.
• Application notes for special installations and limits of the standard (what is— and is not—covered).
• Updated/clarified definitions and technical changes relative to the previous edition (2008), including revised characteristics and selection parameter lists.

Typical use and users

Used by electrical engineers, system designers, plant and facility managers, installers and commissioning teams, SPD manufacturers and test houses, electrical consultants, and certification bodies to define and apply appropriate surge protection strategies for low-voltage power distribution systems in industrial, commercial and residential installations.

Related standards

IEC 61643-12 is one part of the IEC 61643 series on low-voltage surge protective devices. Related standards include product test and performance parts (for example IEC 61643-11) and application-specific parts such as IEC 61643-22 for telecommunications/signalling networks. Installation and risk-assessment standards referenced for coordination and lightning risk considerations include IEC 60364 and IEC 62305-4.

Keywords

surge protective device; SPD; low-voltage; surge protection; overvoltage; lightning protection; measured limiting voltage; coordination; selection; disconnecting device; IEC 61643; power distribution; protection principles.

FAQ

Q: What is this standard?

A: IEC 61643-12:2020 is the third edition of the IEC application standard that sets out selection and application principles for surge protective devices connected to low-voltage power systems (up to 1 000 V RMS).

Q: What does it cover?

A: It covers the principles for assessing the need for SPDs, selecting appropriate devices and characteristics, recommended installation locations and coordination with system insulation and overcurrent protection, practical measures for disconnecting and replacement, and guidance on failure modes and consequences. It does not replace product test standards or cover internal surge-protection components within equipment.

Q: Who typically uses it?

A: Electrical designers, installers, facility managers, SPD manufacturers, testing and certification laboratories, and lightning-protection specialists use this standard to plan and implement surge protection on low-voltage installations.

Q: Is it current or superseded?

A: This edition (3.0) was published in May 2020 and supersedes the 2008 edition (IEC 61643-12:2008). The published document shows the 2020 edition as the current technical revision.

Q: Is it part of a series?

A: Yes. IEC 61643-12 is Part 12 of the IEC 61643 series on low-voltage SPDs. Other parts in the series address product test methods and performance and application to other networks (for example IEC 61643-11 for product requirements and IEC 61643-22 for telecommunications/signalling networks).

Q: What are the key keywords?

A: Key search and indexing terms are: surge protective device, SPD, low-voltage surge protection, selection and application, measured limiting voltage, coordination, lightning protection, IEC 61643.