VSMC said 42 cables totalling 40 kilometers in length had been installed at the site.
VSMC were handed the contract to supply, and install the high-voltage inter-array cables by French developer WPD. Italian firm Prysmian will supply Butendiek's export cables, to be installed by VSMC.
The cables will connect the project to the German grid via the SylWin1 transmission platform.
Last month, Dutch contractor Ballast Nedam completed the installation of the 80 monopiles at the development.
The project will be made up of 80 Siemens 3.6MW turbines and is due to go online next year. The water depth at the site, located approximately 32 kilometres from the island of Sylt, ranges from 17 to 22 metres.