The application relates to an arrangement (1) for mounting on at least one
busbar (4) of a
system (100) for distributing and / or converting electrical energy. The arrangement (1) comprises at least one mounting element (8) that can be mounted on the at least one
busbar (4) and at least one housing unit (6) with an interior (I) in which a plurality of electrical and / or electronic units (6a-6d) are arranged. The mounting element (8) has at least one first fastening element (14a) of a first
pairing (10) of cooperating fastening elements (14a, 14b) and at least one first fastening element (14c) of a second
pairing (12) of fastening elements (14c, 14d) that cooperate as clips, clamps, snaps, hooks, latches and / or locking connections.The at least one housing unit (6) has a second fastening element (14b) of the first
pairing (10) of cooperating fastening elements (14a, 14b) and a second fastening element (14d) of the second pairing (12) of fastening elements (14c, 14d) that cooperate as clips, clamps, snaps, hooks, latches and / or
detent connections. The at least one housing unit (6), particularly as a pre-assembled unit, can be mounted or installed without tools on the mounting element (8) by means of the first pairing (10) of cooperating fastening elements (14a, 14b) and by clipping, clamping, snapping,
hooking, detenting, and / or detenting via the second pairing (12) of cooperating fastening elements (14c, 14d).