On 24/09/2013 09:00, harryagain wrote:

The reason many are sub4Kw is that the smallest charge (money) band is
0-4Kw.
The next is 4-10Kw, too big to fir on most domestic house roofs.

More to the point, 16 A per phase is the maximum current you're allowed
to back-feed into the LV mains without elaborate protection
arrangements and approval of the DNO. (See ENA Engineering
Recommendation G83/2.) This limits you to about 3.8 kVA on a
single-phase connection.

--
Andy