Instrument for surgical cutting

A surgical cutting instrument for use with a motor assembly including a motor housing and a motor driving a drive mechanism, the cutting instrument comprising: an elongate drive member 24 defining a proximal section and a distal section; a cutting tip 26 secured to the distal section of the drive member; a non-conductive coupling body 28 attached to the proximal section of the drive member and adapted for selective attachment to the motor assembly drive mechanism; and a non-conductive housing 30 provided apart from the motor assembly housing, the non-conductive housing encompassing the coupling body and the proximal section of the drive member; wherein the coupling body and the housing are configured to electrically isolate the cutting tip from the motor assembly upon mounting of the cutting instrument to the motor assembly.