Updates to IET Wiring Regulations

17 November 2014

IET announced it will be launching the update to the Wiring Regulations BS 7671:2008 in January 2015.

The amended Wiring Regulations set out the national standard to which all new and amended electrical installations are to comply, and will feature a number of important changes . The publication will be available in both print and digital formats from the IET as of 5th January.

The Amendment 3– which follows on from Amendment No. 1, published back in 2011 and Amendment No.2, published in 2013 – has some important changes which are reflective of recent demands within the electrical sector. The IET, along with JPEL/64, has revised the IET Wiring Regulations to ensure they are relevant and meet the needs of those professionals operating in the electrical industry.

Changes to regulations

Regulation 421.1.201 is just one of the new regulations to be introduced and sets out standards relevant to the domestic installations. As a result of the regulation, consumer units and similar switchgear assemblies will need to comply with BS EN 61439-3 and have their enclosure manufactured from non-combustible material or enclosed in a cabinet, complying with Regulation 132.12. 
The impetus to develop this new requirement came from the London Fire Brigade. Back in June, the Brigade reported that a rising number of domestic house fires were being caused as the result of consumer units catching fire. In fact, the Brigade’s records show that there has been a fivefold rise in this type of fire in the last five years.

Commonly, loose connections within consumer units can lead to overheating – one of the main causes of the units catching fire. With many based under the staircases of residential buildings, such fires can block exit routes and impede the ability to escape.

BS 7671:2008+A3:2015, giving its correct title, is published 5 January 2015. As usual, there is a six-month lead-in period, meaning that the amended Regulations go live at the beginning of July 2015. This requirement  in Regulation 421.1.201 will be delayed by a further six months, coming into effect in January 2016, allowing manufacturers time to produce enclosures in sufficient quantities. 

Another significant change introduced by Amendment No.3 is in Chapter 41 which will highlight the precautions necessary for protection against electric shock. Regulation 411.3.3 will require that, in accordance with 415.1, socket outlets up to 20A must have RCD protection. This will be compulsory for all types of installations, whether they are for commercial, domestic or industrial purposes. For mobile equipment used outdoors this will be mandatory for socket outlets up to 32A. The exception to this requirement is where socket outlets are specifically labelled or where a documented risk assessment deems that RCD protection is not necessary.  

Section 557 is a completely new section introduced by Amendment No.3 covering the required standards for auxiliary circuits in low voltage electrical installations. These circuits are defined as those for the transmission of signals intended for the detection, supervision or control of the functional status of the main circuit. Exempted from this are those circuits for fire and intruder alarms and for example, traffic lights, where specific standards already exist. Section 557 will cover issues such as power supplies for auxiliary circuits, protection against overcurrent and special requirements for those circuits used for measurement.

Revising the old sections

As well as new sections being introduced in Amendment No.3, some older sections have also been revised and updated. Having been introduced in 2008, Section 717 – which covers the standards for mobile and transportable units – will be updated with three new regulations.  

The first of these regulations is Regulation 717.413 which sets out the requirements for the protective measure of electrical separation and is based on the latest CENELEC HD. This will require an insulation monitoring device to be installed so that automatic disconnection of the supply can occur in case of a first fault or an RCD. An earth electrode is installed so that automatic disconnection is provided in the case of failure of the transformer. 

In addition, Regulation 717.551.6 will prohibit the interconnection of units with different power supply systems. The regulation will also prohibit the interconnection of different earthing systems unless special precautions have been taken. What’s more, Regulation 717.551.7.2 will also give additional requirements for installations where the generating set may operate in parallel with other sources. Both of these updates have been designed to reinforce the general rules set out in Part 1 to 6 of BS 7671.

The new requirements set out in the amended IET Wiring Regulations demonstrate the importance of the work electrical professionals do, and the standards they need to adhere to in protecting themselves. With this in mind, it’s absolutely vital that all professionals in the industry familiarise themselves with the new and updated sections set out in Amendment No.3.

The IET will be making the amended Wiring Regulations available from 5 January 2015, both in print and via digital subscription.

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