On 23 Mar 2005 02:43:14 -0800, "Peter M"
wrote:

The other idea I had was to never switch it off!

I have changed the switch, bypassed the buried cable and connected it
via a plug in rcd.
The plug-in rcd trips also.
I think I'll replace the pump with a low-voltage one!

Hi,

Try running the pump in a bucket of water that is well insulated from
the ground, to see if the RCD doesn't trip off.

It could be that water is wicking down through the cable gland in the
pump body, which could be easily fixable with some sealant after
drying out the connections on the other side of the gland.

cheers,
Pete.