Technically you don't need to touch the naked wire, you only need to remove (carefully) the outer insulation and have the two (still insulated) wires separated

Technically you don't need to touch the naked wire, you only need to remove (carefully) the outer insulation and have the two (still insulated) wires separated for a few centimeters. Then there are splitter clamps. The most common ones are used (low voltage) on cars and motorcycles, they look like these: https://www.mesconnettori.it/index.cfm/it/ricerca/?flbr=rubacorrente https://www.mesconnettori.it/index.cfm/it/ricerca/?flbr=ruba... But there are professional ones, suitable to 110 or 240 V example: https://www.techno.it/en/products/all/thb-370-a2a/ https://www.techno.it/en/products/all/thb-370-a2a/