Hello,

Does anyone know of a change over switch to switch between grid
electricity and a local generator? TLC sell two, one is:
http://www.tlc-direct.co.uk/Products/KMT338212I.html

rated at 32A; the other is rated at 63A.

The plan is to have two consumer units. The main one would be grid
connected only and supply most circuits. The second, smaller, CU would
be switched between grid and locally generated power. This second CU
would have three 6A MCBs: one for lights upstairs, one for lights
downstairs, and one for the CH boiler.

Now set-up like this the maximum load is 3*6=18A. Since this is well
below the 32A rating of the switch, can I use this switch? My concern
is that the CU RCD is rated at 80A as are the tails to the CU. If
someone added more MCBs in the future, for the freezer for example,
this could take the load above 32A and the switch would go bang before
everything else.

Should I protect the switch with a 30A fuse to prevent this? Or would
it be the responsibility of whomever added to the system in the future
to make the necessary changes and either add a fuse or upgrade the
switch?

I feel a 80A switch would be the best solution, if you know of one?

I appreciate this kind of work needs a qualified electrician and I
will do so but it's nice to understand what is involved so that I can
understand when I get quotes and different people tell me what they
will do and for how much. It also means I will know what they are on
about and whether what they say needs doing or whether I am being
talked into extra unnecessary work!

Thanks.