Hi,

One or two double sockets *could* mean a load of 40 amps or so. You need
to know how much current you are likely to take. You might, for example,
want to run a 3kW heater and an arc welder together while the pottery oven
is heating up. Or only a desk light and soldering iron.

I will only use the sockets for a small water feature pump and lawn
mower and the lights will be a simple 100w inside and about 150w
outside.

Cheers,

James