A new diagnostic and protective system (DPS) suitable for wheelchair electrical drive applications has been prepared. Such a system is able to perform both monitoring and long-distance transmission of key signals that are used as pre-fault and fault indicators. The system, moreover, may detect several anomalous working conditions by means of reliable diagnosis procedures and carries out actions to protect the electrical drive and to drive the disabled people in safe conditions. In particular the design, the realization and the performance analysis of the new dedicated diagnostic system, which exploits a programmable logic controller (PLC) as DPS hardware, are described and discussed. The effectiveness of the realization has been validated by experimental tests carried out in a laboratory test rig that has been purposely settled up. The experimental results show that the proposed DPS, thanks to the PLC performances, is able to detect the considered anomalous working conditions of the electric drive. Moreover the system is able to choose the correct protective action and to dialogue with a remote control center with trained people able to give first-aid support both in the medical and the technical fields. The information to the disabled people is supplied by means of telediagnostic facilities. The DPS is robust and friendly to use, flexible to program and easy to put on board in a wheelchair.