SURGE PROTECTION

FTES offer the supply, Installation and Maintenance of Surge Protective Devices.

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Surge protection devices are designed to protect against transient overvoltage's and surge conditions. 

Surges can be caused for different reasons such as a lightning strike or through switching of electrical equipment. Large transient overvoltage's can generate up to 6000 volts and can cause immediate or intermittent equipment failure.

Lightning and utility power anomalies only account for 20% of transient surges. 80% of surge activity is produced internally. These surges are smaller, however they occur more frequently and with continuous exposure can degrade sensitive electronic equipment within a facility.

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Surge protection is a requirement of a lightning protection system in compliance with BSEN 62305. Surge protection should therefore be considered during a risk calculation, when designing and installing a lighting protection system.

Surge protection devices are required to services that have incoming and outgoing lines to a structure, such as fire alarm panels, telecoms, data and CCTV. Electrical panel boards and sub distribution boards supplying external equipment.

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There are three different types of Surge Protective Devices: 

• Type 1 SPD installed at the origin, e.g. main distribution board.

• Type 2 SPD installed at sub-distribution boards

  • (Combined Type 1 & 2 SPDs are available and are usually installed in consumer units).

• Type 3 SPD installed close to the protected load. They must be installed as a combined system.

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Surge protection devices are classified according to their standard into different types.
   • Type 1 - SPD which can discharge partial lightning current with a typical waveform 10/350 μs. 
   • Type 2 - SPD which can prevent the spread of overvoltages and protects connected equipment. It has a typical waveform 8/20 μs.
   • Type 3 – These SPDs have a low discharge capacity. They must therefore only be installed as a supplement to Type 2 SPD.

     Type 3 SPD’s are characterised by a combination of voltage waves (1.2/50 μs) and current waves (8/20 μs).

18th edition of the IET wiring regulations

Both BS EN 62305, for protection against lightning, and BS 7671, the 18th edition of the IET Wiring Regulations, detail when, where and why surge protection devices are required. Following the introduction of the 18th Edition of the IET Wiring Regulations further safety measurements have been applied for electrical contractors. A number of important areas have been scrutinised and reviewed; among them is the issue of surge protection and devices designed to mitigate any excess voltage risks. 

Surge protection devices (SPDs) are designed to prevent electric shock and having excess voltage damaging the installation’s wiring infrastructure. Should an over-voltage event occur, the SPD diverts the resulting excess current flow to Earth.

Regulation 443.4 requires, (except for single dwelling units where the total value of the installation and equipment therein does not justify such protection), that protection against transient over-voltages is provided where the consequence caused by over-voltage could result in serious injury, damage to culturally sensitive places, interruption of supply or affect large numbers of co-located persons or loss of life.

When should surge protection be fitted?

For all installations a risk assessment should be carried out to determine whether SPDs should be installed. Where a risk assessment is not carried out, then SPDs should be installed. Electrical installations in single dwelling units are not required to have SPDs installed, however in specific circumstances it may be that in discussion with a client they choose to have such devices installed, reducing significantly risks associated with transient over-voltages.

This is something that many contractors have not previously had to consider during design and planning of a project or when considering maintenance of a property. It will need to be taken in to account both in terms of time allocation for a project as well as additional costs for the customer. All electronic equipment can be vulnerable to transient over-voltages, which can be caused by lightning activity or switching. This could cause serious damage or significantly reduce a piece of equipment’s lifespan which can have high financial implications.

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The requirement for SPDs depend on various factors. 

• The level of exposure of a building to lightning-induced voltage transients.

• The sensitivity and value of the equipment.

• The type of equipment used within the installation/structure.

• If there is any equipment within the structure/installation that could generate voltage transients.

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Responsibility of risk assessments for surge protection are now with the contractor however we offer the support and guidance so that they can effortlessly integrate this aspect and ensure adherence to the new regulations.

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Inspection, Testing & Maintenance

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Inspection and testing of surge protection devices and/or combined systems is essential to ensure that they remain in good working order and in accordance with the relevant standards and manufacturer’s guidance. Devices and systems which are not maintained may not be effective in preventing lightning currents and transient overvoltage's. This could therefore cause the device or combined devices to fail and they would therefore not protect against potential fires, electrocution, and electrical systems/equipment failure.

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FTES offer maintenance and inspection and testing to existing and new surge protection systems, we recommend that inspections are regularly conducted to ensure that protective systems are effective at all times.  

As part of our service we provide surveys and reports to existing systems to ensure they are fully compliant, plus details of any repairs required to return systems to a serviceable condition.

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Recommendations

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As surge protection devices form part of a lightning protection system it is advisable that you should do the following.

• Check if your property/residence has a lightning protection system in compliance with BSEN 62305.

• Check if there is surge protection installed within your property and whether it is maintained regularly (Recommended to be tested annually at approximately the same time as the lightning protection system test, however it is to be tested separately). 

• Check that if surge protection is installed that it is offering protection to all required services.

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If you are unsure of any of the answers to the above points, then please contact us and we will be happy to assist.

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