Threaded nylon adapter can be used to seal the top of  your M8000 float switch (works with the MS8000 and M5000 too, but not the M5600) so that it may be used in an application which requires that the switch top be submerged in liquid (for example, when placed in the bottom of a chamber to sense when it is empty or when using one low-mounted switch to turn a pump on and another high-mounted switch to turn that pump off). 

Thread the float switch wires through the nylon adapter with the threaded side of the adapter facing the top of the switch.  Screw the adapter to the switch threading, using silicon to insure a water tight bond.  Then thread the float switch wires through a piece of ½” inside diameter tubing long enough to extend above the highest water level.  Squeeze the tubing over the adapter, using silicon to seal the connection (see photograph).

Note that because Madison switches have a tapered NPT threading, you will only be able to turn the adapter 1-2 turns.  This is enough to get a good fit - just use silicon to ensure a water-tight seal.

Warning: Check you application regularly for condensation inside the tubing - if condensation forms and drips onto the wire potting at the top of the switch, the same damage can occur as when the switch is submerged in water.