Wire Splicing / Connecting Cables
Using A Soldering Iron to Join Cables Safely
I would define splicing as a means of permanently joining two or more electrical wires to enable uninterrupted current flow, and the emphasis has to be on uninterrupted flow.
Twisting wire ends together, using tape or connection boxes is fine for short term fixings, but if you need a reliable, safe and practical connection that you can be certain will always work for you, in my opinion you cannot beat a soldering iron.