17th Edition Amendment 3 Wiring Regulations - Consumer Units

A rough guide to the forth coming changes to the Electrical wiring regulations on Domestic Consumer Units.

As you may be aware there are changes being made to the wiring regulations BS 7671 with Amendment 3 which is due to be published in January 2015. One of these changes is expected to involve consumer units installed in household premises and is focused on the material their enclosures are manufactured from.

What is driving the changes?

Investigation into several fires involving plastic consumer units, by the London Fire Brigade, has concluded that a key cause of the fires was substandard cable connections made by the Electrician. These resulted in overheating, which eventually ignited the plastic enclosure.

How has the industry been involved with the proposed changes to consumer units?

As a result of the investigations into consumer unit fires, proposals have been made for changes to the Wiring Regulations. All the Blue chip manufacturors have been closely involved in the development of these changes by providing expert industry liaison with interested bodies including; London Fire Brigade, Government and the Joint IET/BSI Technical Committee JPEL/64 which has the responsibility for the content of BS 7671 (17th Edition Wiring Regulations).

Anticipated new regulation

The new Regulation 421.1.201 is expected to state:

Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439 3 and shall:

1. Have their enclosures manufactured from non-combustible material, or
2. Be enclosed in a cabinet or enclosure constructed of non-combustible material and complying with Regulation 132.12.

Note 1: Ferrous metal e.g. steel is deemed to be an example of a non-combustible material.
Note 2:* the implementation date for this regulation is the 1st January 2016. This does not preclude compliance with this regulation prior to this date.

What impact will this have?

This would mean that eventually all new consumer units installed in UK homes, i.e. within domestic (household) premises must have their enclosures manufactured from a non-combustible material, or be enclosed in a cabinet or enclosure constructed from a non-combustible material. This is likely to result in an increased use of metal enclosures.

What is meant by ‘within domestic (household) premises’?

It is understood that Regulation 421.1.201 applies to consumer units and similar switchgear assemblies to BS EN 61439-3 inside all domestic (household) premises including their integral/attached garages and outbuildings or those in close proximity.