How can I extend this outdoor signal cable with waterproof?

Question

I need to repair a broken cable with four wires but there will be no option to solder. So I have to use a screw terminal to extend the cable. The broken cable looks like as follows:

And here is the screw terminal block:

The cable will be on the top of a bridge where there will be rain sometimes. So after I extend the cable by screw terminals I need to find a way to cover the extended section in a way that it wouldn't leak water.

So far I could only find such option as shown here http://www.littlegreenhouse.com/accessory/e-cord-cover.jpg But these are for AC cords I guess.

It is impossible to solder on the top of a bridge and it is long story. So soldering is not an option.

Is there a way to safely cover the terminal block with waterproof. Or any other option to extend with waterproof? Is there any component for such purpose?

Answer 1

You can get waterproof junction boxes - look for an IP rating.

I would consider soldering - I soldered many wires in the middle of farmer's fields - just need a suitable heat source or a low voltage soldering iron.

Answer 2

They make weatherproof aluminum junction boxes such as a Bell or Red Dot, with matching blank lid. To avoid box penetrations, their mounting screws attach to "ears" that attach to the outside of the box. The holes are threaded, as for pipe.

To enter a cable into such a box, take a specimen of your cable (or its measurements) to a proper electrical supply house (which is not anything like an electronics supply house), and get a weatherproof strain-relief cord connector for it. This has a rubber grommet that will compress to seal.

Now if you have cut back your cables too much to fit the junction boxes available, you may need to use two junction boxes, and splice some additional wire between them. You can optionally connect them with threaded pipe instead of having to buy two more strain reliefs.

Answer 3

I wouldn't use a screw terminal block.

Assuming this is for ordinary AC/DC cabling and not high speed data cabling I'd use Wago or similar connections. They're considered maintenance-free, unlike screws which can loosen over time. And enclose in a suitably IP rated enclosure.

http://www.wago.ltd.uk/enclosures/wagobox-capsule/

But if this is a commercial application the "person in charge" should determine an appropriate product that complies with their risk assessment method statement (RAMS) and electrical regulations.