Reliable electrical connections are responsible for the trouble-free operation of entire systems where the load (electric stock) is roughly alternating. This circumstance makes it more complicated to identify the current state of the electrical connection during operation. During operation, the value of the transient resistance increases, as the tightening torque of the clamp dies is reduced (loosening) and the oxide films appear in sites of the wire and clamp joint. For the satisfactory condition, the value of the transient resistance should not exceed the value equal to the ohmic (linear) conductor resistance. Therefore, the aim of this work is the research study and comparison of the mathematical model to assess the state of the electrical connection under operational conditions that indirectly determines the actual value of the transient resistance.