Low voltage plug/socket for underwater in pond

[ARW]

There is always R391 compound.

It was a total failure when I tried to use it on a connection for my parents pond as my Mother thought it was dog shit as swept it up into a shovel and binned it.

[Andy Burns]

If it's 12V, just twist the wires and bung them in a gel-filled IPX8 junction box?

[Colin Bignell]

Do you need a plug and socket, or would a waterproof inline junction box do?

[Tim+]

Brian, Joey is just yet another Rod Speed nym. Save your breath.

Tim

[Chris Green]

That's only waterproof for a big, fat, round mains cable. My wires are either small and round (say 1.5 - 2mm dia) or flexible flat twin (probably 2mm x 4mm).

[Chris Green]

I could use the wago type connectors they suggest rather than twisting the wires together. However I'd need to make the box sink somehow.

[ARW]

On 05/06/2022 14:57, Chris Green wrote: However I'd need to make the box sink somehow.

Superglue a model of the Titanic to it.

[Brian Gaff]

Many moons ago, they used to have some kind of apparently waterproof plugs on bilge pumps on small boats. They seemed to be basically like two pin with a very tight shroud and some kind of silicon sealant you used in the cable inlets. It was a long time ago, who remembers J Birkett who used to sell the pumps. Back in the 70s?? Brian

[Brian Gaff]

That depends of course, Electrolysis is a funny thing. I once submerged an ordinary bakelite chock block in a rainwater barrel and yes it worked the pump for years on 12 v, but when I needed to take it off it looked a bit like an alien life form with whiskers and strangely coloured bits hanging off the metal,of course you had to cut it off! Brian

[Brian Gaff]

I have also come across a kind of cylinder with seals at either end for the wires, but in the middle is just a couple of spade connectors. The tube came in two halves with a kind of square o ring between the parts and some self tapping screws. Seemed to work though it was only being used on a snow blower thingy in Scotland. Maybe its because these sort of plugs are rare that makers just find a fix that works for them? Surely pond and fishy places must have a solution? Brian

[Brian Gaff]

Beware of the garden lights connectors or idc joiners. Most of them go duff after less than a year out in the rain. Brian

[ARW]

On 05/06/2022 16:45, Brian Gaff wrote: who remembers J Birkett who used to

The one on Steep Hill?

[4587Joey]

No problem with the connector on my car or the trailer.

Never had that with either of my trailors or any of my cars.

[charles]

but they aren't underwater.

[4587Joey]

That was a comment about his 'any metal left outside corrodes' nof the op's underwater question.

[Andy Dingley]

First question, do you need a connector or a junction? Do you care if you can unfasten it afterwards?

IMHE, I've made permanent junctions by packing vaseline into a double-ended crimp (regular red / blue ones) and crimping, then glue-lined heatshrink over that (for strain relief as much as anything, and then wrapping well (twice) with self-amalg tape, It's also useful to put some real strain relief into it with some tie-wraps (a big long unfastened one, held in place by a couple of little ones at each end).

I've also used various commercial IP68 joiners and connectors, which can be retrieved after use and opened up easily, which is handy when they fail every couple of years.

If you do go for the waterproof box with choc block inside, crimps (maybe Wagos?) are more reliable than screws for giving a useful connection even once it's "damp" in there.

[Theo]

Since this is DC, unless you keep them dry you're setting up an electrochemical cell with the connectors as electrodes and the pond water as electrolyte. It's then a question of how much current flows through the cell, given it's in parallel with a presumably low resistance pump - depends on the conductivity of the water. But if the pump were to fail or be internally switched, I'd expect the full current to be going through the water. This might be rather corrosive (and harmful to fish).

OTOH, it could be that you generate some hydrogen which blows out the water from the connector... but it'll seep back in again, generate more H2 to dry it again, rinse and repeat.

Theo

[Robin]

I don't see why the failure of the pump would have much effect. And my rough calculation suggested 12 V between a pair of Wago 221s a cm or 2 apart in water with conductivity of a few hundred microS/cm would give rise to no more than about 10 mA. But I don't have a pond to hand to see if a reality agrees with my envelope.

[The Natural Philosopher]

Hot glue is allegedly good here, if you already have it.

[The Natural Philosopher]

less corrosion under fresh water than in air - less oxygen.