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Furse, Wilford Road, Nottingham, NG2 1EB • Tel: +44 (0)115 964 3700 • Email:
enquiry@furse.com• Web:
www.furse.comBS EN 61643 standard series
TSC-0912 - 09.10.12
Furse SPDs meet the performance parameters
defined in two national & 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 overvoltages.
BS EN 61643-11 covers AC mains protection, for
50/60 Hz AC power circuits and equipment rated up
to 1000 V
RMS
AC and 1500 V DC.
BS EN 61643-21 covers telecommunications and
signalling networks with nominal system voltages up
to 1000 V
RMS
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
1
), 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 overcurrent protective devices
Through following the guidance in these documents,
appropriate specification of SPDs to meet the
installation requirement can be achieved.
1
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.