The access gallery for the tunnel pumped-storage power station in the canton of Valais required adequate illumination. The 6 km long gallery was provided with 300 lights, with every fourth light also serving as an emergency light. The 24 flat cable harnesses with a length of 250 m were equipped with 20 lights each. The lights were mounted on a kerb with a height of approximately 1 m. The StreamLED has a high protection class (IP68 / 69 K), and its compact design means that it can be installed quickly and easily. The gallery is now illuminated as requested, thereby ensuring that it is safe to access.