Barriers and Enclosures

[seftonbarn]

Firstly can I check my understanding. Consumer Units on the sides and bottom and front should afford IP2X / IPXXB (Test finger 12.5mm and 80mm long) and readily accessible top surfaces affording IP4X / IPXXD (1mm dia 100mm long)? Is this right?

And if it is, does anyone understand the logic of this? Why can you have a 12.5mm gap on the sides but on the top it must not be more than 1mm.

 

[amlu]

its to avoiding something metal (screw, key, nail etc) falling into the consumer unit via a big hole on the top of it, shorting out the bus bars and making a bang?

 

[telectrix]

in other words, a combination of ohms law and newton's.

 

[seftonbarn]

Thanks, yes, that would makle sense. Perhaps newton's law when combined with sod's law and ohm's law is why we are limted to 1mm at the top.

 

[Silly Sausage]

What's the required IP rating now of a 'Non-combustible' CU with fire proof cable entries?

 

[uksparks]

What's the required IP rating now of a 'Non-combustible' CU with fire proof cable entries?

They have probably not thought of that one yet!