What are the IET BS7671 Wiring Regulations?


Every electrician in the UK must comply with BS7671 regulations – better known as the Wiring Regulations or “the regs”.

Published by the British Standards Institution (BSI), the Wiring Regulations are written by the Institution of Engineering and Technology (IET). The IET is a comparatively recent amalgamation of the Institute of Electrical Engineers (IEE) and the Institution of Incorporated Engineers – organisations that were established more than 130 years ago. The first edition of the Wiring Regulations was published in 1882.

What is a power surge?


Last year saw the publication of the BS7671 Wiring Regulations: 18th Edition, and one of the changes in this latest version is to do with transient overvoltage protection, also known as surge protection.

A surge is a momentary increase in electrical power, which can cause damage to electrical equipment. Potentially, it can endanger lives. This type of power surge is most commonly caused by lightning strikes.

What is a fuse for?


In the UK, all electrical appliances are protected to some degree by a fuse. A fuse is made up of a thin conductor wire within an insulated casing, designed to cope with a limited level of electrical power. The thicker the wire, the more power it can handle.

A fuse is part of an electrical circuit. If a surge occurs, the wire within the fuse burns out and cuts off the power supply from the consumer unit. This is a mandatory safety measure present in all UK electrical installations.


What is a surge protection device?


A transient overvoltage protection device, also known as a surge protection device (SPD), also serves the purpose of dealing with power surges. The SPD, however, is a more sophisticated piece of equipment. It does the job without shutting everything down!

Basically, an SPD is a bad conductor – a metal oxide material that won’t conduct electricity below a certain voltage. However, when the voltage rises during a surge, the semi-conductor can’t withstand the power, and it conducts the current away through the Ground (Earth) route. Nothing blows, trips, or burns out; everything just carries on as normal.


When must an SPD be used?


The 18th edition of the wiring regulations requires SPDs to be installed if overvoltage could:

1.      result in serious injury or loss of life

2.      cause interruption of public services

3.      cause damage to cultural heritage

4.      interrupt commercial or industrial activity

5.      affect a large number of co-located individuals

But where an SPD is not required, a risk assessment must be carried out.

Even in the family home, surge protection is a safety measure that could, ultimately, save lives.

To talk to us about the installation of an SPD, just give us a call on 01603 559 311.

Alternatively, contact us here.