Free download BS EN IEC Standards for Surge Protective Device (SPD)


Our SPDs meet the performance parameters defined in the International & European standards:

  • BS EN 61643-11 Surge protective devices connected to low-voltage power systems – requirements and tests
  • BS EN 61643-21 Surge protective devices connected to telecommunications and signalling networks – performance requirements and testing methods

These parts of the BS EN 61643 standard apply for all SPDs providing protection against lightning (direct and indirect) and transient over-voltages.

BS EN 61643-11 covers AC mains protection, for 50/60 Hz AC power circuits and equipment rated up to 1000 VRMS AC and 1500 V DC.

BS EN 61643-21 covers telecommunications and signalling networks with nominal system voltages up to 1000 VRMS AC and 1500 V DC.

Within these parts to the standard is defined:

  • The electrical requirements for SPDs, including voltage protection and current limiting levels, status indication and minimum test performance
  • The mechanical requirements for SPDs, to ensure an appropriate quality of connection, and mechanical stability when mounted
  • The safety performance of the SPD, including its mechanical strength and its ability to withstand heat, overstress and insulation resistance

The standard establishes the importance of testing SPDs to determine their electrical, mechanical and safety performance.

Electrical tests include impulse durability, current limiting, and transmission tests.

Mechanical and safety tests establish levels of protection against direct contact, water, impact, the SPD installed environment etc.

For voltage and current limiting performance, an SPD is tested according to its Type (or Class to IEC), which defines the level of lightning current or transient overvoltage it is expected to limit/divert away from sensitive equipment.

Tests include Class I impulse current, Class I & II nominal discharge current, Class I & II voltage impulse and Class III combination wave tests for SPDs installed on power lines, and Class D (high energy), C (fast rate of rise), and B (slow rate of rise) for those on data, signal and telecoms lines.

SPDs are tested with the connections or terminations following manufacturer’s instructions, as per the expected SPD installation.

Measurements are taken at the connectors/terminals. Three samples of an SPD are tested and all must pass before approval is granted.

SPDs which have been tested to BS EN 61643 should be suitably labelled and marked, to include the relevant performance data for their application.

Technical Specifications

Within BS EN 61643 there are two Technical Specifications which provide recommendations on the selection and installation of SPDs.

These are:

  • DD CLC/TS 61643-12 Surge protective devices connected to low-voltage power systems – selection and application principles
  • DD CLC/TS 61643-22 Surge protective devices connected to telecommunications and signalling networks – selection and application principles

These Technical Specifications should be used with BS EN 61643-11 and BS EN 61643-21 respectively.

Each Technical Specification provides information and guidance on:

  • Risk assessment and evaluating the need for SPDs in low-voltage systems, with reference to IEC 62305 Lightning protection standard and IEC 60364 Electrical installations for buildings
  • Important characteristics of an SPD (e.g. voltage protection level) in conjunction with the protection needs of equipment (i.e. its impulse withstand or impulse immunity)
  • Selection of SPDs considering the entire installation environment, including their classification, function & performance
  • Coordination of SPDs throughout the installation (for power and data lines) and between SPDs and RCDs or over-current protective devices

Through following the guidance in these documents, the appropriate specification of SPDs to meet the installation requirement can be achieved.

Type 1, 2, or 3 SPDs to BS EN/EN 61643-11 are comparable to Class I, Class II and Class III SPDs to IEC 61643-11 respectively.

Awareness, that transient surges are the main influencing factor of the MTBF (Mean Time Between Failures) of systems and equipment, is driving all manufacturers in the area of surge protection to continuously develop new overvoltage protective devices with increasing features and in compliance with the actual international & european standards. The following is a list of the key standards involved:

Protection against lightning – Part 1: General principlesEuropean Norm EN Logo

EN 62305-2:2011

Protection against lightning – Part 2: Risk management

EN 62305-3:2011

Protection against lightning – Part 3: Physical damage to structures and live hazard

EN 62305-4:2011

Protection against lightning – Part 4: Electrical and electronic systems within structures

EN 62561-1:2017

Lightning Protection System Components (LPSC) – Part 1: Requirements for connection components

BS EN 61643-11:2012+A11:2018British Standards BSI Logo

Low-voltage surge protective devices – Part 11 Surge protective devices connected to low-voltage power systems – Requirements and test methods

Low-voltage surge protective devices – Surge protective devices for specific application including d.c. – Part 11 Requirements and tests for SPDs in photovoltaic applications

BS EN 61643-21:2001+A2:2013

Low-voltage surge protective devices – Part 21 Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods

IEC 62305-1:2010

Protection against lightning – Part 1 General principlesInternational Electrotechnical Commission IEC Logo

IEC 62305-2:2010

Protection against lightning – Part 2 Risk management

IEC 62305-3:2010

Protection against lightning – Part 3: Physical damage to structures and live hazard

IEC 62305-4:2010

Protection against lightning – Part 4: Electrical and electronic systems within structures

IEC 62561-1:2012

Lightning Protection System Components (LPSC) – Part 1: Requirements for connection components

IEC 61643-11:2011

Low-voltage surge protective devices – Part 11: Surge protective devices connected to low-voltage power systems – Requirements and test methods

Low-voltage surge protective devices – Part 31: Requirements and test methods for SPDs for photovoltaic installations

IEC 61643-21:2012

Low voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods

IEC 61643-22:2015

Low-voltage surge protective devices – Part 22: Surge protective devices connected to telecommunications and signalling networks – Selection and application principles

IEC 61643-32:2017

Low-voltage surge protective devices – Part 32: Surge protective devices connected to the d.c. side of photovoltaic installations – Selection and application principles

IEC 60364-5-53:2015

Electrical installations of buildings – Part 5-53: Selection and erection of electrical equipments – Isolation, switching and control

IEC 61000-4-5:2014

Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement techniques – Surge immunity test.

IEC 61643-12:2008

Low-voltage surge protective devices – Part 12: Surge protective devices connected to low-voltage power distribution systems – Selection and application principles

Components for low-voltage surge protective devices – Part 331: Performance requirements and test methods for metal oxide varistors (MOV)

IEC 61643-311-2013

Components for low-voltage surge protective devices – Part 311: Performance requirements and test circuits for gas discharge tubes (GDT)