Dussman Service Deutschland GmbH                                       Building services engineering
               
 Entega Gebäudetechnik GmbH & Co. KG           Building services engineering, low voltage cable installations
               
 Essety Deutschland / SCA GmbH           Process control engineering
               
Heberger Hoch-, Tief- und Ingenieurbau GmbH           Medium voltage cable installations
               
Hoyer Gruppe           Building services engineering, DGUV Regulation 3
               
IMB Stromversorgungs Systeme GmbH           Medium voltage cable installations
               
Kieback & Peter GmbH & Co. KG           Process control engineering
               
MVV Umwelt O&M GmbH           Process control engineering, building services engineering, medium voltage cable installations
               
STRIPF Project Solutions GmbH           Process control engineering