Metal CUs Update

by Editor on December 29, 2015

Confused about the Amendment 3 metal consumer unit regs? Although I’ve been installing them since July 2015, Hagar’s recent feature in PE magazine and the videos below will help to dispell any misconceptions and they’ve also set me right on a few things.

Here’s a quick look at recommendations for installation of non-combustible consumer unit enclosures:

Jan 2016
The 17th EditionĀ  Amendment 3 metal consumer unit regulation reg 421.1.201 was issued in January 2015 but didn’t officially come into effect into effect until 1 January 2016.

Fireproofing
Hagar say that additional fireproofing of their metal enclosures by using cable glands or intumescent materials isn’t nescessary. Testing has proven that a fire caused by a poor connection would be adequately contained within the metal enclosure. Obviously glands, trunking and grommets should be fitted at the descretion of the installer to achieve the required IP rating.

Report Plastic as C3?
For inspection reporting on EICRs, any plastic/insulated/combustible consumer units only need to be noted as C3 (Requiring improvement):

  • Where installed under a wooden staircase
  • If they are located within the sole means of escape from a building or in a fire escape
  • If they don’t comply to the manufacturer’s specifications or have been modified.

Note- The connections inside the CU should be checked/torqued as part of the EICR in all cases.

CUs In Garages
Consumer units should be metal (non-combustible) when located in garages or outhouses that are linked to dwellings.
For plastic CUs in detatched buildings, a risk assessment should be carried out relating to the spread of fire to the house.

Metal Truking & Blanks
Plastic trunking and blanks are “compliant to the intent of the regulation”. This would suggest that metal trunking is not a requirement as any fire would be contained within the metal enclosure. Plastic blanks would also be acceptable as they would be behind the metal cover.

Metal CUs for TT Systems
For TT Systems the main supply tails are should be protected from damage and disturbance (and therefore from becoming lose).
A DP “S” type RCCB acting as a main switch would be a good option for giving fault protection to the tails feeding & entering the consumer unit.

More about 17th EditionĀ  Amendment 3 Regulation 421.1.201


ElectriciansBlog.co.uk

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