Protecting electrical wiring

If I do need to join wires (I prefer to run a length without joins as this will always be the first point of failure), then I use these which I get from work.
 
You insert the wires in the holes as far as they will go (no need to bare the wires) then press down on the red button. I use a pair of pliers for this.
 
Inside is a metal link which cuts through the insulation making contact with the conductor, as well as a waterproof gel which seales the holes where the wires are inserted.
 
Used them on extending a cable to a point motor, with no problems....

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