The IET recently published an article in Wiring Matters – Special Edition 55 that explains when installers should begin to use non-combustible consumer units i.e. put simply the answer is, as soon as stocks are available.
Amendment 3 to BS 7671:2011 (IET Wiring Regulations Seventeenth Edition) came into effect on 1 July 2015. It included a new regulation requiring consumer units and similar switchgear assemblies that are installed into domestic household premises to have a non-combustible enclosure. This new regulation (421.1.201) stated – Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and shall either have their enclosure manufactured from non-combustible material, or be enclosed in a cabinet or enclosure constructed of non-combustible material. Two footnotes are attached to this regulation:-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 was the 1st January 2016, but does not preclude compliance with the regulation prior to that date Note 2 is further explained in Wiring Matters as follows “The purpose of the delay in implementation is to allow a period of co-existence of both metal- and plastic-enclosed consumer units and to allow time for manufacturers to work existing and new products through their supply chains. Nevertheless, as is also indicated in Note 2, the delayed implementation does not preclude compliance with the regulation prior to 1 January 2016”
Therefore installers can comply with the new regulation (which is intended to as far as is reasonably practicable, contain any fire within the enclosure or cabinet and to minimise the escape of flames) as soon as the stocks are within the supply chain.
Source: http://www.electrium.co.uk/news/when-should-installers-start-to-use-non-combustible-consumer-units