A new design of terminal pumping has been installed in an existing 3 MV Pelletron tandem accelerator. The very limited space in the high voltage terminal (total length 600 mm and diameter 600 mm and housing equipment for two charging-chain systems and a double valve equipment, the latter to be used in connection with stripper foil replacement) and the absence of electrical power in the terminal, required an unusual design for the installation and powering of the new pumps. Technical details of the design as well as some preliminary experience of the use of the new system, especially for accelerator mass spectrometry, will be given. ©1999 American Institute of Physics.