Furse - Lightning & Transient Over-Voltage Protection

Lightning & Transient Over-Voltage Protection System - Earthing Surge Arrestors

Total Solution to Lightning Protection, Earthing & Transient Overvoltage Protection Requirements

From design advice to innovative, solution-oriented products, Furse has the expertise, experience and excellence to provide a Total Solution to your individual lightning protection, transient overvoltage and earthing problems.

Lightning Protection Standards - out with the old, in with the new

BS 6551 was the national standard that the UK (and other parts of the world) adhered to for over twenty years. BS EN 62305, which was published at the end of August 2006, ran in parallel with BS 6651 for 2 years, eventually replacing it on 1st September 2008. With BS 6551 now obsolete, BS EN 62305: 2011 (second edition) is therefore the only applicable standard relevant to lightning protection.

BS EN 62305 includes the requirements of BS EN 50164 Series of standards. BS EN 50164 is a ratified European standard relating to the capabilities of lightning protection components.

BS EN 62305, following on from the published IEC (World) and CENELEC (European) versions of IEC/EN 62305 is a four part standard consisting of General principles; Risk management; Physical damage to structures and life hazard; and Electrical & electronic systems within structures.

BS EN 62305 Part 1 is an introduction to the other parts of the standard and essentially describes how to design a Lightning Protection System (LPS) in accordance with the accompanying parts of the standard.

BS EN 62305 Part 2 risk management is a very detailed approach to the risk of lightning inflicted damage to structures, their contents (electronic equipment) and living beings. It identifies different risk components that collectively are compared to a tolerable risk. It is a very long-winded process when carrying out the assessment long hand. A computer program is commercially available from Furse to considerably reduce the time to implement the risk procedure.

BS EN 62305 Part 3 relates directly to the major part of BS 6651. It differs from BS 6651 in as much that it has four classes or protection levels of Lightning Protection System (LPS), as opposed to the basic two (ordinary and high-risk) levels in BS 6651.

BS EN 62305 Part 4 covers the protection of electrical and electronic systems housed within structures. This part essentially embodies what annex C in BS 6651 detailed, but with a new zonal approach referred to as Lightning Protection Zones (LPZ). It provides information for the design, installation, maintenance and testing of a Lightning Electromagnetic Impulse (LEMP) protection system for electrical/electronic systems within a structure.

Structural Lightning Protection

It is vital that buildings are designed and equipped with a lightning protection system that will ensure the safety of the structure, and its occupants. Given the importance of bonding and proper connection of the components of the lightning protection system (LPS), just one faulty or poor quality component can lead to costly damage, even fatalities.

The Furse range of lightning protection products, designed and manufactured to the highest standards, consists of: flat, solid circular and stranded conductors in copper and aluminium, many of which are available PVC covered for greater aesthetic appeal. Furse also offer a large range of air terminals, fittings, bonds, clamps and lightning current/equipotential bonding surge protective devices (SPDs). In accordance with BS EN 62305, these SPDs are required where direct connection with bonding conductors is not suitable - for example metallic power and telecommunication lines. We also offer a free design and advisory service for lightning protection to BS EN 62305, or any other recognized standard.

Effective Earthing

The dangers posed to both life and equipment by poor earthing make effective earthing essential. Given the complexity of national and international standards in earthing system design, material specification and installation, it makes sense to talk to Furse.

Furse design and model earthing electrode systems in compliance with BS 7430:1998, IEEE standard 80:2000, BS 7354:1992, EATS 41-24:1992 and other accepted standards. The comprehensive Furse range of earthing equipment includes solid copper, stainless steel and copperbond earth rods and accessories, high copper alloy bonds and clamps, earth pits, solid copper plates, lattice mats, earth rod seals and the FurseWELD exothermic welding system.

Electronic Systems Protection

BS 6651 had an informative annex C giving the reader recommendations on the implementation of surge protection devices (SPDs).

BS EN 62305 now has transient overvoltage protection as an integral part of the standard (BS EN 62305-4), governed by the single risk assessment of BS EN 62305-2. Where required by BS EN 62305, SPDs shall be selected and installed in accordance with the IET Wiring Regulations (BS 7671:2008 +A1:2011, Section 534).

Even with the best available structural lightning protection, the electrical and electronic contents of a building are at risk from the secondary effects of lightning - transient overvoltages. Lightning activity can create sub- millisecond transient overvoltages of up to 6,000 V on power, data, signal and telephone lines. Transients destroy, damage or degrade the electronic components of the equipment through which they pass on their route to earth. Transients can also occur on mains power supplies within the building through electrical switching events. Any piece of equipment incorporating electronic components is at risk: from computers and PBX to fire alarms and even Uninterruptible Power Supplies.

To prevent transient damage, SPDs should be fitted on all metallic power, data communication, signal and telephone lines where they enter or leave a building. The Furse ESP range includes SPDs for most applications, including mains power, data or signal lines, telephone lines, CCTV/CATV video cables, coaxial RF lines and Ethernet networks.

Technical Assistance

Detailed technical guidance is available from Furse engineers in Nottingham, and our field-based engineers can provide site surveys and protection proposals.