A splice is a connector used to join two wire ends together end-to-end, typically to extend a circuit's length or repair a damaged section of cable without replacing the entire run.

The most common types are crimp butt splices, which mechanically compress the two wire ends inside a metal sleeve, and heat-shrink splices, which add a heat-activated sealing sleeve over the crimp for extra moisture and strain protection.

Match the splice's rated wire gauge range to the actual conductor size being joined — an undersized splice won't accept the full strand count for a proper crimp, while an oversized one won't compress tightly enough for a reliable connection.

A properly crimped splice, made with the correct tool and die, provides a mechanically strong and electrically reliable connection suitable for most industrial and automotive applications, and is generally faster and more consistent to install than soldering in the field.

Heat-shrink splices are the better choice for vibration-prone or outdoor/damp applications, since the heat-shrink sleeve seals out moisture and adds strain relief that a plain crimp splice alone doesn't provide.