The 5th January 2015 publication of the latest version of BS7671 will introduce the 3rd Amendment to the 17th Edition of the IET Wiring Regulations. The enforcement of the content within the latest edition of the Wiring Regulations will be required from July 2015, with new regulations for the design, installation and commissioning of electrical installations, plus inspection and testing. It is important for electricians to get up to speed with Amendment 3 and its changes, advises Carole Jameson, Training Centre Administration Manager at PASS Electrical Training.

Electricians now have just over six months to revise the new regulations and make any necessary adjustments to their methods and working practices. According to the IET, there are clearly a lot of questions around the changes, particularly concerning consumer units.

In this update, a number of potentially life-saving changes have been proposed, which include changes to consumer unit enclosures to come into effect January 2016 and wiring in escape routes. These suggested improvements have come through from London Fire Brigade (LFB), who has been consulting with Electrical Safety First and the manufacturers’ association (BEAMA).

The reason that LFB has driven for these changes is because of the amount of fires that a consumer unit is identified as the source of ignition – currently around five a week. Over recent years LFB has recognised a large increase in the number of consumer unit related fires as shown in the accompanying diagram.

Clearly there is a dangerous trend occurring here. LFB thinks this increase to be mainly due to consumer units with components which are subject to product recall, manufacturers mainly using moulded plastics for consumer unit casings and cables not being securely tightened when installation or maintenance is carried out on the installation.

The secondary concern that LFB has raised is that the consumer units are quite often installed in a cupboard under the stairs. This raises concerns as the stairway is obviously an essential pathway for an emergency escape in a fire scenario and if the fire was to start from the consumer unit it would not take a long time for the escape route to become engulfed by fire and impossible to use.

LFB has also contributed with the introduction of new requirements for cabling installed above ceilings that are liable to collapse in a fire (suspended ceilings for example).

Other changes include changes to earth fault loop impedances for all protective devices, the risk assessment approach for the omission of RCDs in non-domestic situations, updated EIC and electrical installation condition report (EICR) forms for electrical contractors, and changes to definitions throughout the Wiring Regulations.

As in previous revisions to the Wiring Regulations, Amendment 3 is backed by an updated On-Site Guide, which gets down to the specific works on small scale electrical installations, as well as Guidance Notes covering assorted issues like isolation of outdoor lighting, circuit-breakers used as switches, changes to earth fault loop impedances for all protective devices, earth electrode testing, heating equipment, and protection against electric shock and overcurrent.

Special Locations
Guidance Note 7 Special Locations is for anyone working with electrical installations in specific locations where guidance may vary such as bathrooms, outdoors and medical locations. Amendment 3 changes include cables in bathrooms, outdoor lighting, extra low voltage (ELV) lighting, and mobile and transportable units.

Some of the potential changes to the current 17th Edition Regulations are expected in Part 2 Definitions. This section could be expanded and modified with some of the terminology changing to avoid confusion and promote further clarity.

As for specific chapters, Chapter 52 Selection and Erection of the Wiring Cables: Cables concealed in a wall or partition, could be rewritten and all references to the phrase ‘under the supervision of skilled and instructed persons’ may be removed.

Section 557 Auxiliary Circuits is a proposed new addition to the regulations and will cover things like auxiliary circuits for low voltage electrical installations. These types of circuits are for the transmission of signals intended for the detection, supervision or control of the functional status of a main circuit.

Section 717 Mobile and Transportable Units – This covers units which are self propelled, towed or transportable containers or cabins. Risk reduction requirements include automatic disconnection by RCD, accessible conductive parts to be connected through equipotential bonding to the main earth terminal within the unit, and the type of supply, voltage rating, number of phases, on board earthing and maximum power required.

Section 559, 714 and 715: Luminaires and Lighting Installations – Changes are proposed to bring this section together with the latest IEC and CENELEC standards.

Section 715 Extra-low Voltage Lighting – This refers to installations supplied from sources with maximum rated voltage of 50V AC or 120V DC. With respect to Section 714 Outdoor Lighting Installations, only minor changes are proposed in this section including things like requiring individual circuits to be isolated.

As for Chapter 41 Protection against Electric Shock, it is proposed that any reference to ‘ordinary persons’ is removed and protection for socket outlets up to 20A for all installations is required. However, those with RCD protection for specific labelled socket outlets or where a risk assessment has decided that RCD protection is not necessary are exempt.

Cmin factor
It is proposed that the maximum earth fault loop impedance is revised to account of the Cmin factor – the minimum voltage factor to take account of voltage variations depending on time and place, changing of transformer taps and other considerations. Notes on the tables will be changed to reflect maximum permitted operating temperature.

Chapter 42 Protection against Thermal Effects – Regulation 421.1200 requires switchgear assemblies including consumer units to have their enclosure manufactured from non combustible material to help protect against fire.

A few changes are proposed to the electrical installation condition report and notes. It proposes changes to the certification of new work – the schedule of inspections for new work to be replaced by examples of items that require inspection during initial verification.

PASS runs a number of one day 3rd Amendment seminars aimed at raising awareness of these changes among electricians and helping to interpret its content throughout the UK.

For further information, please visit PASS Ltd’s specialist 3rd Amendment web page or call 0845 365 3945.