Tomography assembly for electric resistance tomography in a drillhole

The arrangement has a bore hole piping including electrical conducting material for lining bore holes (1, 2), where the piping is made of steel. Tomography electrodes (10, 11) are provided for a power supply in a bore hole environment and for voltage measurement from the environment, where the electrodes are attached at the piping. An isolation layer is attached on the piping to electrically isolate the piping against the electrodes, where the isolation layer and the electrodes are arranged at an outer side of the piping. An independent claim is also included for a method for manufacturing and/or operating a tomography arrangement.