CPV code 50116100 designates Electrical-system repair services in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
50116100 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 50116000 (Maintenance and repair services related to specific parts of vehicles).