Furse Total Solution to Earthing & Lightning Protection

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Furse, Wilford Road, Nottingham, NG2 1EB • Tel: +44 (0)115 964 3700 • Email: • Web:
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Introduction Protecting electronic systems
The importance of electronic systems protection
Electronic systems have become central to
virtually every aspect of our lives from PCs and
building management systems in the office to
automated petrol pumps and barcode scanners
at the supermarket.
The ever-changing pace of technological development,
and especially the headlong quest for miniaturisation,
has created the scenario where increasingly lightning
sensitive systems are placed at the core of our society.
Both the threat of damage to vital electronic systems,
and the seriousness of the consequences of that
damage, are more real than ever before.
Most modern electronic systems are at risk:
computers
data communication networks
building management systems
PABX telephone exchanges
CCTV equipment
fire and burglar alarms
telecom base stations
uninterruptible power supplies (UPSs)
programmable logic controllers (PLCs)
plant sensors
telemetry and data acquisition equipment
Loss of these systems would cripple industrial,
commercial and government organisations alike.
The importance of electronic systems protection, often
referred to as surge protection, is now defined in many
standards, including BS EN/IEC 62305 and BS 7671.
Indeed, BS EN/IEC 62305 requires integrated structural
and surge protection. In effect structural lightning
protection can no longer be considered in isolation to
the protection of electronic systems.
Transient overvoltages
The main risk to internal systems is through transient
overvoltages - large, very brief and potentially
destructive increases in voltage within the electrical
system.
Transient overvoltages can be caused by:
the secondary effects of lightning strikes (either
between clouds or to ground) from a kilometre
or more, away, from lightning energy induced
on to above or below ground power, data and
signal lines
the electrical switching of large inductive loads
(such as motors, transformers and electrical
drives), or capacitive loads (such as power factor
correction)
Transient overvoltage
damage to the circuit
board in the image
left, is clear to see, but
most damage is barely
visible, as shown in
the image below.