lets remind ourselves of the definions ( per IEC 60664-1, Insulation coordination for equipment within low-voltage systems - Part 1: Principles, requirements and tests)

Pollution Degree 1: No pollution or only dry, non-conductive pollution occurs. The pollution has no effect.

Pollution Degree 2: Normally only non-conductive pollution occurs. Temporary conductivity caused by condensation is to be expected.

Pollution Degree 3: Conductive pollution or dry non-conductive pollution that becomes conductive due to condensation. To be found in industrial environment or construction sites (harsh environments).

Pollution Degree 4: The pollution generates persistent conductivity e.g. conductive dust, rain, or snow.

What happens in practice is less clear cut.

Now you can site your indoor grade electrics outside, in a meter cabinet perhaps, and while things are exposed to a cat 4 effect outside on a rainy day, inside the meter cabinet, out of the rain, all is at worst category 2. But if someone smashes the meter cabinet door it is no longer true ;-) 

But under an overhang things suddenly get less severe again...

So in a rain proof box  - your example of IP65 enclosure would meet this-  all is well.

Mike

mapj1 said:

meter cabinet perhaps

I am not sure I agree with that above statement.  Maybe it should read in a secondary meter cabinet perhaps. as the ENA (The Energy Networks Association) say that customer kit is not permitted in the intake meter box. 

Although this enclosure is provided with the property, the distributor will specify that only equipment belonging to the distributor and meter operator (MOP) should be installed therein.

From memory I think it is Appendix B G87 I will have a hunt around for it later

OK, perhaps a crossed wire there,  - for clarity the reason that meters and isolators and so on can be put in that style of cabinet outdoors is because it provides protection against rain etc.

Actually it is far from unknown to see two side by side, one with company meter and maybe just an isolator, and the other with customer side CU etc. I was not suggesting that along side the actual meter was the only place to put a CU - just that that style of enclosure is a good example of the right sort of protection.

M.

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