Mount for CU

[whyme!]

Looking to build a cupboard for the eventual mounting of a consumer unit. Is it ok to mount onto ply or would a cement board be better. Prefer to have a full height ply sheet 18mm so I can mount other things on at some point.
Also have ply on some batten so cables can enter from rear.

 

[Iggifer]

http://www.cef.co.uk/catalogue/products/1939239-11-inch-x-9-inch-flame-retardant-meter-board

Other sizes and suppliers are available

 

[whyme!]

Is ply ok though for all back wall. Does it have to be flame retardant if you have an amendment 3 case? Reading case spech it says "Tests on Hager consumer units have indicated that there is no specific need for fire rated cable glands or intumescent sealing in addition to the IP ratings below, with respect to achieving a non-combustible enclosure"

Or mount it on the studs with plasterboard back so cables are hidden behind plasterbaord

 

[EFLImpudence]

Ply and battens are fine.

All amendment 3 says is that the Consumer Unit must be made from non-combustible material.

Anything else you read is conjecture.

 

[Risteard]

All amendment 3 says is that the Consumer Unit must be made from non-combustible material.

It doesn't even state that. That is simply one of the two options listed.

 

[EFLImpudence]

True - or it must be in a biscuit tin.

 

[whyme!]

Good have all cables hidden then, just looks nicer in my opinion

 

[ericmark]

Be it a fuse, MCB or RCBO they produce heat, that's how they work, so any cupboard must have ventilation or another path for the energy to get out of the consumer unit.

 

[flyingsparks]

Be it a fuse, MCB or RCBO they produce heat, that's how they work, so any cupboard must have ventilation or another path for the energy to get out of the consumer unit.

I'm not being funny but the amount of heat is hardly worth worrying about. How about the extremely well sealed consumer unit with its ip2x and ip4x top and sides and glands. Not much ventilation inside there!

 

[ericmark]

I'm not being funny but the amount of heat is hardly worth worrying about. How about the extremely well sealed consumer unit with its ip2x and ip4x top and sides and glands. Not much ventilation inside there!

So the metal box of the consumer unit is an insulator? Does not matter how the heat is got rid of, can be through the wall it is mounted on, but it does need to escape.

 

[whyme!]

Surely if it is in a metal box and sealed to delay fire it is difficult to ventilate. So long as it has air around it is that not enough for ventilating? I guess i could fit a fan to it but is that really needed?

 

[JohnW2]

Surely if it is in a metal box and sealed to delay fire it is difficult to ventilate.

For better or for worse, the regulation says nothing about delaying the spread of fire. It would seem that, provided it was made from a 'non-combustible material' (which does not even exist!) a CU could be absolutely full of holes (provided they were small enough not to the violate the IP requirements) and still be compliant.

It is often said that the regulations are not necessarily meant to make any sense. This one seems to be a good illustration of that, for a whole host of reasons.

Kind Regards, John

 

[EFLImpudence]

Consumer Units - especially metal ones do not need ventilation.

 

[whyme!]

Considering the money they charge for the Hager empty tin, a few blanks would have been nice and more than one knockout seal.