Wire Splice
A wire splice is the connection where two conductors are joined end to end. Electrically, the resistance of the splice must be close to the cable's own resistance, and mechanically the splice must carry no tensile load at all. A correct splice is made with a crimped connection or a terminal block, not by twisting and taping.
The wrong splice we see most often in the field is two ends twisted together with insulating tape wrapped over them. There is no contact pressure in this connection; the twisted strands oxidise before long, the resistance rises, the area heats up and the tape softens and unwinds. The result is an intermittent contact or a burnt harness appearing months later.
- Crimped butt splice: it crimps both ends in a single barrel; it is the right solution for a vibrating environment.
- Terminal block splice: it is made inside a junction box, and being removable and measurable is an advantage.
- Insulation: the splice is closed off with adhesive-lined heat-shrink tubing; tape does not count as permanent insulation.
- Position: the splice must be in a fixed and clamped area, not in a moving or flexing one.
Wherever possible, prefer to run the cable in one piece end to end instead of splicing. If a splice is unavoidable, mark its location on the diagram; it is one of the first points to check when looking for a fault later.
The context in which this term is used: Installation, redundancy and field continuity