My situation was in the bottom of an underground vault which houses several pumps for decorative ponds as well as an electric panel, timeclocks etc.
A sump pump was installed at the bottom of the vault. That particular float was installed to allow the pump to run even when a small amount of water entered it. We used a simple "RIB" relay to operate the pump. I know the pump operated quite frequently and as I said no problems to date.
