Portable work apparatus, such as an expander, cutter or combination device with a cutting and expanding function for example, for portable use, having a housing, an electric motor located in the housing, a power supply in the form of a rechargeable battery accommodated on the work apparatus or in the form of a connection for connection to an external electrical power source, a mechanically or hydraulically driven, displaceable piston rod for performing work, in particular expanding work and/or cutting work and/or lifting and/or compressing work, an electronic open-loop control and closed-loop control device for open-loop control and/or closed-loop control of the electric motor, which comprises at least one printed circuit board (8, 20, 22) on which electronic components are arranged, and also at least one control cable (10a, 10b) for transporting control signals, wherein the control cable (10a, 10b) has connection means for connection to the printed circuit board (8, 20, 22), characterized in that the electric motor provided is a brushless DC motor, the electronic components of a first printed circuit board are surrounded by potting compound in order to protect against entry of water, the connection means of the control cable (10a, 10b) are protected against an ingress of water, wherein the connection means provided are plug connections, no protective and/or sealing measures against an entry of water into the interior of the housing when the housing is immersed in water are provided on the housing and an insert shaft with open contact pins, not protected against water and located in said insert shaft, for making contact with the rechargeable battery is provided for the purpose of accommodating the rechargeable battery, wherein the contact pins are at a sufficient distance away from one another to ensure that, if the contact pins are surrounded by water, an electrical short circuit is not established via the water as an electrical conduction medium under the electrical operating conditions of the work apparatus. a housing, an electric motor located in the housing, a power supply in the form of a rechargeable battery accommodated on the work apparatus or in the form of a connection for connection to an external electrical power source, a mechanically or hydraulically driven, displaceable piston rod for performing work, in particular expanding work and/or cutting work and/or lifting and/or compressing work, an electronic open-loop control and closed-loop control device for open-loop control and/or closed-loop control of the electric motor, which comprises at least one printed circuit board (8, 20, 22) on which electronic components are arranged, and also at least one control cable (10a, 10b) for transporting control signals, wherein the control cable (10a, 10b) has connection means for connection to the printed circuit board (8, 20, 22), characterized in that the electric motor provided is a brushless DC motor, the electronic components of a first printed circuit board are surrounded by potting compound in order to protect against entry of water, the connection means of the control cable (10a, 10b) are protected against an ingress of water, wherein the connection means provided are plug connections, no protective and/or sealing measures against an entry of water into the interior of the housing when the housing is immersed in water are provided on the housing and an insert shaft with open contact pins, not protected against water and located in said insert shaft, for making contact with the rechargeable battery is provided for the purpose of accommodating the rechargeable battery, wherein the contact pins are at a sufficient distance away from one another to ensure that, if the contact pins are surrounded by water, an electrical short circuit is not established via the water as an electrical conduction medium under the electrical operating conditions of the work apparatus.