A tree pruner (1) has a drive engine (2) or motor, a cutting head (4), and a stem (3) with a drive shaft (15) linking the engine or motor to the head. There is a protective sleeve (16) surrounding the drive shaft. The drive shaft (15) and the protective sleeve (16) are of electrical insulating material, so that the stem (3) electrically isolates the head from the engine or motor. The sleeve (16) and shaft (19) insulating material is fibreglass. The drive shaft insulated section (19) is located between proximal (17) and distal (18) sections of the drive shaft (15). Hence, the drive shaft (15) may be coupled with the engine (2) and the head (4) in a normal manner as is conventional. Electrical safety is achieved despite the fact that the shaft in in the conductive path from the head to the engine, and this may be required to transmit high torque and/or speed. <；Figure 2>；
