SURGE & CIRCUIT PROTECTION FEATURE
...More generally, the 18th edition requires installation of SPDs according to BS EN 62305 where there is a risk of direct lightning strike to the structure itself or to overhead lines connected with it. Beyond the 18th edition, changes are also planned to the BS EN and IEC 62305 standards. Publication of Edition 3 of IEC 62305, the international lightning protection standard, is planned before the end of 2018 by the International Electrotechnical Committee (IEC). The BS EN version will follow once CENELEC (European Committee for Electrotechnical Standardisation) has reviewed and integrated changes to apply to the UK and European.
HOW CAN THE INDUSTRY PREPARE FOR THE CHANGES? A simple way to prepare is to use SPDs that have been developed and tested against the latest product standards, which ensures they will
provide protection against repeated ‘worst case’ transients. Furse publishes detailed guidance on surge protection on its website. With multiple types of SPD being available for mains, signal and telecoms lines, it’s worth being aware of the different Types and applications. For example, Type 1 power SPDs
protect against dangerous sparking following a lightning strike, when high voltages can exceed the limits of cable or equipment insulation, leading to flashover. Type 1 SPDs should be installed at the service entrance and protect against loss of life and in BS EN 62305, they are also called equipotential bonding SPDs. - However, Type 1 SPDs do not protect electrical or electronic components against transient overvoltages from lightning or switching. To achieve this, Type 2 and Type 3 overvoltage SPDs will further reduce overvoltages to levels that are safe for sensitive electronics. Together Types 1, 2 and 3 are
known as a coordinated SPD set. Some combined SPDs are also available and these achieve the function of two or more types within a single SPD unit, saving both cost and installation time.
ABB
www.abb.co.uk
ELECTRICAL ENGINEERING | MAY 2018 41
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
