In prior art, it is impossible to continuously monitor the state of a contact surface coating of individual contacts. The aim of the invention is to enable said type of continuous state monitoring of the contact surface coating as simply as possible. Said aim is achieved in that sensors (4, 4', 4'') are introduced into a contact surface coating (2) which is applied to a contact base material (1). The sensors (4, 4', 4'') are in particular nanostructures, the conductance thereof being significantly higher than the conductance of the contact surface coating (2). If the contact surface coating (2) is removed by wear and tear, for example due to the counter contact of a tongue (3), then at least some sensors (4, 4', 4'') are destroyed. The results of a corresponding conductivity measurement by means of the measurement device (5) provides a significant statistical indication on the state of the contact surface coating (2).