By definition, multi core cables have an outer sheath which surrounds all of the inner conductors. This is usually in the form of an extruded PVC or cross-linked polyethylene jacket, often combined with an aluminium sheath under the surface for electromagnetic shielding. In many applications, this jacket adds significant mechanical protection, making the cable much more rugged. Sometimes each individual connection or channel also has its own jacket to aid mechanical or electromagnetic protection.

Some multi core cables terminate in a multi pin connector, often circular. Others split the cores into separate cables at the ends, terminating in a mass of connectors. This type of end is often called a fan or tail.

Submersible Round Cable

Multi core cables can be used for analog and digital signals as well as power distribution. They are often used to simplify the physical setup of a system and provide a neater connection between two pieces of equipment. For example, in sound reinforcement, a multi core cable is often used to connect all the microphones on stage to the mixing console. This is much easier than running many individual cables, which can become messy and time consuming.

Some multi core cables combine different types of connections, such as a Siamese cable which typically consists of power and coaxial conductors. This type of multi core is often advantageous in home wiring as it minimises the number of cables run through the sub floor or ceiling cavity of a building.