BS 7671 - Surge Protection Section (534)

Surge Protection - Latest BS 7671 Wiring Regulations

A new key section (534) within the latest edition of BS 7671 Wiring Regulations published on the 1 July 2011 came into  effect on 1 January 2012.

Section (534) now sees a requirement for all new electrical installations designed after 1 January 2012 to include the correct selection and installation of a SPD's (Surge Protection Device).

This requirement is to provide protection against over voltages from atmospheric origin (lightning) or electrical switching events both of which are capable of severely effecting electrical installations and connected equipment.

The risks to life, buildings and electronics due to over voltages are detailed within BS EN 62305 'Protection Against Lightning' with the standard clearly detailing a risk assessment to establish the type and level of SPD's required.

Churchill offer a full range of SPD's manufactured by the world's leading suppliers, this is supported by free comprehensive advice together with free seminars to larger clients explaining the fundamentals of SPD's.

The most popular SPD on the market and the one most commonly installed is the Furse ESP 415 M1 which is an enhanced protector for three phase supplies of 346 - 484 volts, for single phase supplies of 200 - 280 volts the ESP 240 M1 should be employed.

For more information of SPD's call our helpdesk on 0844 504 9998

Surge Protection

When designing lightning protection it's important to consider adequate surge protection. On a smaller scale people protect their treasured home electrical devices with surge protection devices, on a larger scale devices are available to protect a wide range of items such as servers, communications, data storage, telephony etc.

There are a number of forms of protection needed against surges as there is more than one type of surge. One type of surge is transient over voltages which are short duration high magnitude voltage peaks with fast rising edges, often described as "spikes". The most common cause of these spikes is lightning strikes, but they can be caused by electrical switching when there is increased demand placed upon an electrical system it becomes overpowered. These surges can cause devastating damage to systems that are not protected. The most severe damage is to cable installation which in a worst case scenario can result in fatalities through either electric shocks or fire. Other damages can be to electrical and electronic equipment resulting in data loss, degradation and equipment failure. These aspects can cost a company a lot of revenue, in terms of a loss of productivity, product spoilage, staff overtime and delays to clients, not forgetting sales lost to competitors when your business is unable to run smoothly.

There are different types of surge protection devices dependent on the type of transient over-voltage. Direct lightning strikes are protected by lightning current or equipotential bonding SPDs. Indirect lightning strikes and switching transients are protected by transient over-voltage SPDs. The main purpose of lightning current and equipotential  bonding SPD's are to prevent sparking from cable damage by lightning strike, so the site does not become a fire hazard. Transient over-voltage SPD's are there to protect against secondary effects of indirect lightning and switching transients such as data loss and equipment failure.

There are certain areas that require surge protection in order for the protection to be adequate. You need to protect all cables which enter and leave a building including mains power supplies (including UPS), data communication and local are network cables, signal, control, instrumentation and alarm lines, CCTV, satellite, TV and antenna cables and telephone and telemetry lines. It is also important to protect the power supply local to important equipment, electronic equipment outside the main building.

Whatever the surge protection needed you can get both surge protection devices and advice from Churchill Specialist Contracting.