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Consumer Unit Blanking Plates

Former Community Member
Former Community Member

It is conceivable that a loose live conductor could come into contact with a metal blanking plate.  Some of the twist-on  types do not make electrical contact with the (earthed / powder-coated) case in which case they thus constitute exposed conductive parts.  This means that they should be individually earthed. But there is no means provided to do do this.  So the question is: does the use of metal CU blanking plates contravene the Wiring Regulations if fitted but not earthed?

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    And to confuse matters some clip on front covers for sockets are not earthed either…

    Decorative covers on sockets etc. would usually be separated from live parts by reinforced insulation (i.e. the insulating body of the socket housing).

    I guess the worry is that blanks on a CU might come into contact with wiring with only basic insulation. The obvious answer is to ask the manufacurer. I've not used any of these metallic blanks yet, so not sure of the exact design, but might suspect that normally wiring wouldn't come particularly near to them - terminals of MCBs etc would normally be considerably higher (or lower) than the opening and it would be unusual to run wiring in front of the DIN rail - so the manufacturer might consider than the blanks not to be liable to become live even if basic insulation failed. That might be different if there were good cause to run wiring to something immediately behind the blank - e.g. DIN rail mounted terminals - but then most CU manufacturers don't supply such things as part of their CU range so you'd be back to the old chestnut about using components not specified by the manufacturer so you become responsible for the assembly and type testing etc. 

       - Andy.

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  • 0

    And to confuse matters some clip on front covers for sockets are not earthed either…

    Decorative covers on sockets etc. would usually be separated from live parts by reinforced insulation (i.e. the insulating body of the socket housing).

    I guess the worry is that blanks on a CU might come into contact with wiring with only basic insulation. The obvious answer is to ask the manufacurer. I've not used any of these metallic blanks yet, so not sure of the exact design, but might suspect that normally wiring wouldn't come particularly near to them - terminals of MCBs etc would normally be considerably higher (or lower) than the opening and it would be unusual to run wiring in front of the DIN rail - so the manufacturer might consider than the blanks not to be liable to become live even if basic insulation failed. That might be different if there were good cause to run wiring to something immediately behind the blank - e.g. DIN rail mounted terminals - but then most CU manufacturers don't supply such things as part of their CU range so you'd be back to the old chestnut about using components not specified by the manufacturer so you become responsible for the assembly and type testing etc. 

       - Andy.

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