ground layers of modern composite layer printed wiring boards are utilized according to the principles of the invention fig2 is a side elevational view of a multi layer printed wiring board having electronic devices populated thereon in accordance with the principles of the invention with reference to fig2 a first integrated circuit 20 is populated on the multi layer printed wiring board 22 a second integrated circuit 24 is populated on the composite layer printed wiring board 22 a heat pipe 26 is attached directly to the ground layer copper traces on the printed wiring board at a position between the first integrated circuit 20 and the second integrated circuit 24 according to another specific embodiment of the invention the composite layer printed wiring board is embodied as an eight layer board the power and ground layers in the eight layer board are thickened to 0 007 34 whereas the other conductive layers used for signal interconnections in the board are 0 0015 34 thick if the power and ground layers are thickened as taught herein the temperature of the board at the location of each integrated circuit is reduced by about 13 u00b0 f as compared to an eight layer board in which all the layers are 0 0015 34 thick when the heat pipe is connected to a location on the layer of the printed wiring board between first and second integrated circuits equidistant from the first and second integrated circuits and the power and ground layers.