Surge Protection
The FM Sudafix Group provides a complete surge protection range and can even manufacture bespoke units; those products are detailed in our catalogue which you can order.
Surge protection has always been closely linked to lightning protection systems due to the logical link between the management of, and protection against, substantial fault currents. It is pertinent to consider that a structure is usually at greater threat from lightning surge current damage than from the threat of a direct lightning strike.
The previous iteration of lightning protection standard, BS 6651, held information on integrating surge protection devices within an appendix; however BS EN (IEC) 62305 now holds surge protection as a distinct aspect of the standard (part 4), which must be addressed in any structure that claims to be compliant with this standard. BS EN (IEC) 62305-4 recommends a number of methods to protect against transient overvoltages cause by lightning, such as effective earthing and bonding, electromagnetic shielding and line routing, and importantly coordinated surge protection devices; these measures directly impact on the performance of the internal measures of a lightning protection system. The function of the internal lightning protection system is to prevent dangerous sparking between areas of differing electrical potentials, and to prevent the fault currents causing damage in the form of fires, explosions or equipment damage.
A philosophy which underpins the whole of BS EN 62305 is that of lightning protection zones. The concept is that any complex, facility, building or room can be split into zones which have different requirements for lightning protection, and then appropriate protection measures can be broken down into that particular zone. A building may have an external lightning protection system that will stop the building from being damaged, or catching fire. Inside the building there may be equipment such as a computer server within a dedicated room. The server will need further protection to ensure that it is protected from surges, therefore being a lightning protection zone, within a lightning protection zone. It is always worth remembering to attempt to surge protect locally to equipment to ensure that it is managed effectively, and to avoid allowing fault currents inducting downstream of the surge protection device.
Surges can carry through data, power and telephone lines and it is prudent to install surge protection measures on the local power supply to vital equipment, any electronic equipment outside the main structure; particular attention should be given to cables which penetrate the external envelope of the structure. Examples of such items can include CCTV systems, air handling units, power, data and telecom lines, meteorological sensors, aerials, antennas or satellite dish receivers.
Surge performance requirements:
There are three surge protection device classifications: Class I, for protection against direct lightning currents (which is a lightning current arrestor) which activates based upon a 10/350 microsecond current profile. Class II, for protection against indirect lightning effects (which is installed ‘downstream’ from the lightning arrestor) and it is based upon an 8/20 microsecond current profile. Finally there is a Class III surge protection device which is designed for protection against switching overvoltages or localized surges, its performance is based upon a 1.2/50 microsecond and 8/20 microsecond current profile. Some devices can serve as a combined class I and class II device, but it is always important to clarify their performance.
Requirements to install:
As surge protection devices are directly incorporated into electrical circuits it is imperative that they are installed by a trained and competent person. Anyone lacking training and experience in working with electrical circuits should not attempt to install a surge protection device.
Preparation and installation:
Prior to any installation the circuit into which the surge protection device is being installed must be isolated and terminated at the mains. Working in an electrically live area is a potentially lethal hazard and should be avoided. Health and safety measures should be in place to prevent any surge protection device installation works occurring on live circuits. As the installation of a surge protection device is dependent upon the sort of device being installed it is not possible to provide any further information, beyond reasserting the need for all installations to follow the site and task specific installation method statement.
If you require further information about our surge protection please refer to our surge protection dedicated website
Website : www.surgeprotectionsystems.com
Online Catalogue : Surge Protection
