The cable outer surrounds the core and contains materials to protect the cable and house the fibre optic cable.

Who supplies them

Materials: Commodity suppliers.

Fibre optic manufacturers: Hexatronic and Huber+Suhner.

Fibre optic jointers and systems: Aceda and CCL UK.

Key facts

For a three-core cable, the cores are surrounded by non-conductive filling and packing material made from polypropylene. Its purpose is to maintain the cable’s shape and structure. All are then bound together with tape into a single cable.

A layer of polypropylene string is applied over the assembly as bedding for the armour wires.

The armouring is usually made up of helical metal wires surrounding the cable. Armouring wires are usually made from either stainless steel or non-magnetic galvanised steel. The choice of armouring is important as impacts the cable’s protective, handling, and electrical properties.

Dynamic cables require two layers of armouring, compared to a single layer for static cables. This is to provide the cable with additional fatigue resistance.

Bitumen may be applied over the armouring to protect against corrosion and to provide additional adhesion.

Static cables use a layer of polypropylene yarn over the armour, to provide resistance to abrasion and to reduce friction during laying. It is applied with a black and yellow pattern to make the cable visible during laying.

Dynamic cables use a polyethene sheath on the outer layer rather than polypropylene yarn. This is to provide additional fatigue resistance to the cable.

At least one fibre optic cable is integrated into the power cable for communications. The cable is multimodal, meaning that it can carry a wide range of data at different frequencies, typically for voice, turbine, switchgear, condition monitoring and security information. A fibre optic cable typically has 48 strands.

What’s in it

Guide to a Floating Offshore Wind Farm