An arrangement for cooling subassemblies of an automation or control system is disclosed, wherein the subassemblies each comprise at least one printed circuit board (LP) having electronic components of different temperature sensitivity arranged thereon. The printed circuit board (LP) has at least one first portion for temperature-sensitive components and at least one second portion for temperature-insensitive components that generate waste heat. Interspaces are arranged between the first portion and the second portion, the interspaces each forming a thermally insulated trench. Means can be provided which keep away the heat over the temperature-sensitive components in a suitable manner and dissipate the waste heat from the printed circuit board (LP) before the heat reaches the temperature-sensitive components.