230V mains power will generally maintain a usable voltage even over a long narrow run like that though.
You should see the problems you get with relatively short runs of 24V cable for garden lighting... voltage drops all over the place.
Personally with gardening equipment the best sollution is to install proper blue Ceeform sockets around the garden on posts fed with properly rated, properly burried sheilded cable run inside heavy conduit.
Overhere it's normal practice to fuse them at 13 amps and have a local RCD fitted.
That minimises the use of ridiculously long extension cords and ensures good protection as well as removing water permiable domestic plugs from the garden.
In a british/irish climate it's really insane to continue to use electrical equipment in potentially wet grass without proper connectors and proper RCDs etc..
Although, I do have an elderly relative who used BS546 15 amp trailing sockets and plugs in the garden on a regular basis
big old round black ones from the 40s!
[This message has been edited by djk (edited 07-28-2003).]