Amendment 3 was a hot topic after new requirements came into effect on 1st January 2016. But Electrium is warning ‘it’s not all just about Consumer Units’, as it introduces several additions to its Wylex range.
Over the last year or more, there has been a lot of coverage in the trade press about Amendment 3 of the 17th edition of the wiring regulations. It is interesting to note, however, that the new Regulation 421.1.201, the non-combustible consumer unit requirement, was in fact born out of practical observation.
The London Fire Brigade had found that there were around five incidents of fire per week involving plastic consumer units. The majority of these incidents were as a result of poor quality electrical connections. Furthermore, the positioning of consumer units, often located near an exit door or under the stairs, was also of concern, as such a fire could spread to coats and other household items, thereby rapidly taking hold. The intention of the amendment to the Regs therefore was to contain any fire within the circuit protection equipment enclosure, hence preventing a major incident.
As a consequence, manufacturers of circuit protection equipment in particular have taken great trouble to educate us all with the detail of specific compliant products that are now available to use in a domestic wiring installation. But in the process of doing this, little or no emphasis has been placed on how Regulation 421.1.201 in Amendment 3 is not just about non-combustible enclosures for consumer units. This new regulation requires the use of non-combustible enclosures for similar switchgear assemblies too.
To be clear, “similar switchgear assemblies” means switchgear that is used for the same fundamental purpose as a consumer unit i.e. for circuit protection applications within domestic household premises. So we need to be unambiguous about this phrase. The wiring regulations give us a definition of a consumer unit, and quite simply similar switchgear assemblies are assemblies of a similar construction to a consumer unit. An example, for instance, would be an assembly with an incoming circuit with a double pole main switch coupled with one or more protective devices, such as a spine unit, garage unit or a switched fuse, all used for the same fundamental application as a consumer unit.
Wylex range
This is why Wylex has introduced several additions to its Amendment 3 range. As well as the NM range of consumer units, there is a range of Meter Cabinet Consumer Units (previously known as Skeleton Units) in full non-combustible all-metal enclosures. These bespoke units are designed for use in high-rise and similar applications, where the electricity meter is housed within a cabinet outside the dwelling and the consumer unit is located in the same enclosure in the space above the meter.
In addition, there is a brand new range of Domestic Switch Fuse Units in all-metal non-combustible enclosures. These dedicated sub main switch fuse units are designed to make the installation and connection of sub-mains or system extensions easy, and are used wherever large buildings are being converted into several apartments. Wylex Domestic Switch Fuse units are available in three ratings 60A, 80A and 100A, and un-fused versions and spare fuses rated from 40A to 100A are also available.
A mains tails entry gland is included in the range to cater for the IET on-site guide recommendations that where metal consumer units are installed into TT applications the mains tails are protected against the possibility of becoming loose and making contact with the metal enclosure (it also recommends incorporating into TT installations 100mA time delayed (S type) RCCB protection). Furthermore, in all cases (including TT), the mains tails should be protected at the point of entry into any of these metal enclosures e.g. by use of a mains tails gland or other suitable method to protect against the possibility of mechanical damage and or disturbance that could lead to tails making contact with the metal enclosure. In addition, to further enhance the fire safety standards that are intended by regulation 421.1.201, Wylex has introduced a range of accessories including intumescents, flame retardant grommets, and non-combustible blanks.
As you would expect, all Wylex domestic circuit protection units meet the requirements of the relevant product standards (BS EN 61439) and the latest requirements of BS7671 Wiring Regulations including Amendment 3.
