"Wanderer" wrote in message
...

You've also got to think of generator earthing. Most leccy companies
will allow you to bond to their earth terminal *providing* the
incoming supply is PME.

But BS 7671 does not allow you to "rely upon the connection to the earthed
point of the public supply system when the generator is operating as a
switched alternative to a TN system" [Reg 551-04-03] so an independent earth
electrode is required - although it can be bonded to the PME terminal.

There is a whole section (551) of BS 7671 devoted to 'generating sets' -
which includes staic UPSs, BTW - that anyone seriously intending to install
permananent private generation should study. Liaison with the supplier
(network operator) is essential, as are interlocked switching (so you can't
back-feed the mains) and automatic load shedding if your genny isn't big
enough to supply the whole maximum demand.

--
Andy