Over the weekend I pulled the feed to the fountain out, put a plug on it, decided on a 5A fuse (0.75mm^2 cable) and powered it up. Much to my surprise it worked.
My next problem is that /she/ doesn't want a cable across the lawn to the nearest power (my shed/office). So I have to arrange something else.
It seems to me I have two choices:
(1) Bury SWA across the lawn. Swap the switch box for one that will take SWA. Put a junction box on the outside of my shed/office where it's dry, and a little fly lead so it doesn't count as fixed into the outside socket.
(2) Run SWA along the flower bed from where the switch box already exists along to the house. Put a junction on the wall near the house, then a flylead into the house. Longer term, when the kitchen is refitted put an outside socket there, or even feed the SWA from the house - I'll need a pro electrician at refit time anyway. (thinking about it, some spare SWA on that choice would be a good idea).
The pump and filter both seem to have the same cable, which is black and I suspect rubber of some sort, and the same 0.75mm size. Is it even permitted to run these into a switch box these days? Is there a junction box that will take SWA and normal cable, and survive being rained on?
I've never handled SWA (but I do have some leather gloves!) so any other suggestions gratefully received.
It's all fed by RCDs - in the shed case at both ends of its SWA feed - advice and suggestions please.