Slightly OT: Joining cables to be used under water....

[Vargster <vargster@xxxxxxxxx>]

I've got to join two cables to make a watertight seal... how?

To explain, I've installed a 1500 litre tank in the garden to collect
rainwater to be used to flush the toilets in the house.
There is a small pump in the bottom of this tank, to pump the water up to a
new header tank in the loft, before it comes down again to the toilets.

The problem is that the pump comes with a 1 metre lead power. It's a
lightweight flexible mains cable, but it only carries 12V, I've got to
extend this to get power to the pump outside the tank.
The real problem is that the tank is 1.8 metres deep, meaning that a lot of
the time the joint will be under water...

I've tried soldering the cables together, then giving it a couple of thick
coats of silicone sealant, which seems to work, but on further inspection
the sealant does bond too well to the cables outer sheath. Sanding the
sheath to rough finish doesn't help either.

Keeping the pump at the bottom of the tank seems the best plan as it will
generally be away from any ice that may form in the tank, though to be fair
I haven't seen any ice in there, even on days when my "control
bucket" of
rainwater has 1/2" of ice on it.

I've thought about floating the pump on a styrofoam pontoon on the surface
of the water in the tank, but the pump is the size of a coke can, and
weighs
nothing, which causes a problem of what to do with the 15mm+ of fairly
rigid
hose that takes the water out the pump and out of the tank...

Any ideas, solutions, thoughts, etc gratefully accepted...
Lee

PS. Bringing it right back on topic, of course it's going to be controlled
by the HA server...


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