Integrating renewable energy applications such as photovoltaic power plants or electrolysers into the grid requires a high power density and therefore high currents in the order of several kilo amperes. As Joule heating is proportional to the current squared, significant losses and temperature rise have to be taken into consideration when developing system solutions. To maximize the current carrying capacity, which is desirable for the cost effectiveness and potential overload reliability of the components, the generated thermal losses need to be dissipated. This paper explores integration of various cooling concepts into a predetermined rectifier unit design with its constructive limitations. The objective is to assess experimentally the possibilities for extending the current carrying capacity of bus bars in the design while retaining the given spatial arrangement of components, bus bar configuration, and dimensions. For that, a laboratory test setup with two aluminium bus bars with a cross-section of 3000 mm² each is presented and their thermal performance for various loads and cooling concepts is evaluated.