By October 7, 2020 Read More →

Surge protection devices for domestic dwellings

The Surge Shield range of surge protection devices is available from specialist distributor Switchtec.

Switchtec has developed the Surge Shield series of Retrofit Surge Protection units to meet the requirements of the 18th Edition regulations BS7671:2018. This range of easy to install enclosed surge protection devices are prewired and preinstalled in surface mounted enclosures designed to be installed in parallel to existing consumer units. Designed specifically for retrofitting where existing consumer units are installed, they provide protection for electrical appliances against surges, where it is not possible to accommodate an SPD directly within the existing consumer unit due to space limitations.

These Type 2 SPD’s are suitable to installation in most domestic or commercial properties without external lighting protection systems (Lightning Rods). The range includes IP20 Metal Clad TT/TN SPD’s with either a 20KA or 40KA SPD. The standard unit is fitted with a 100A main switch, whilst other units are fitted with Type C MCB’s for additional circuit protection. Versions are also available in IP65 Polycarbonate enclosures where a weatherproof installation is needed. The Surge Shield unitises surge protection devices manufactured by Citel, who have over 80 years’ experience in the manufacture of surge protection. The SPD’s are manufactured in accordance to IEC61643-11 and recognised by external test laboratories including EAC, IEC, VDE and cULus.

This range has been developed to meet the requirements as detailed in the 18th Edition regulation 443.4. This requires protection against transient overvoltage’s to be provided where the consequence caused by overvoltage could cause serious injury or loss of human life, interruption of public services and/or damage to cultural heritage, interruption of commercial or industrial activity, or could affect a large number of coinhabited people.

Under other circumstances a risk assessment must be carried out to see if protection is necessary. The risk assessment calculation is based on a formula that uses values including high and low voltage overhead cable length along with high and low voltage underground cable length, plus values related to geographical location in the UK. This is information which can be obtained from the DNO, but which can be time consuming and difficult to obtain. If no risk assessment has been carried out then protection must be provided.

With the availability of such units, their ease of installation plus the complex nature of the assessment, it is therefore often easier and advisable to fit a Surge Shield SPD.

Further information can be found at

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