On 03/04/2020 13:27, Harry Bloomfield wrote:
Chris Green expressed precisely :
Very few 'submersible' pumps are rated for permanent submersion.* I
used one in a similar situation and it failed (as in tripped the RCD)
after a year or so.

I would suggest they were poor quality or faulty from the start. I have
installed many such pumps - they run happily and been submerged for
decades.
I agree. At my last house I installed a submersible in a well. It worked
perfectly of the 12 years before we moved.

Mike