Electrical power transmission system of a vehicle, for delivering electrical power from an electrical power source to an electrical appliance, wherein a circuit breaker is connected between the electrical power source and a first conductor (5.01), which is further connected to the electrical appliance, wherein the electrical power source and the electrical appliance are connected to the chassis of the vehicle, which acts as a conductor for conducting an electrical current between the electrical appliance and the electrical power source, wherein: a) a second conductor (5.02) is connected between the circuit breaker and the electrical appliance, wherein the first and the second conductor (5.01, 5.02) are electrically isolated and connected in parallel, wherein the first and second conductor (5.01, 5.02) are arranged to both transmit electrical power of the electrical power source, b) a first current sensor (56.1) is arranged to sense a first current in the first conductor (5.01) and a second current sensor (56.2) is arranged to sense a second current in the second conductor (5.02), and c) an analysis and control unit is arranged, in order to analyze the first and the second current and to control an operating state of the circuit breaker and/or to indicate a fault state based on the analysis of the first and the second current, characterized in that d) a first communication device (6.0, 6.1, 6.2) is arranged at a first coupling point in order to couple a communication signal into respectively out from the first and second conductor (5.01, 5.02) and/or the further first and second conductors (5.11, 5.21, 5.21, 5.22), and e) a second communication device (6.0, 6.1, 6.2) is arranged at a second coupling point in order to couple a communication signal into respectively out from the first and second conductor (5.01, 5.02) and/or the further first and second conductors (5.11, 5.21, 5.21, 5.22). a) a second conductor (5.02) is connected between the circuit breaker and the electrical appliance, wherein the first and the second conductor (5.01, 5.02) are electrically isolated and connected in parallel, wherein the first and second conductor (5.01, 5.02) are arranged to both transmit electrical power of the electrical power source, b) a first current sensor (56.1) is arranged to sense a first current in the first conductor (5.01) and a second current sensor (56.2) is arranged to sense a second current in the second conductor (5.02), and c) an analysis and control unit is arranged, in order to analyze the first and the second current and to control an operating state of the circuit breaker and/or to indicate a fault state based on the analysis of the first and the second current, characterized in that d) a first communication device (6.0, 6.1, 6.2) is arranged at a first coupling point in order to couple a communication signal into respectively out from the first and second conductor (5.01, 5.02) and/or the further first and second conductors (5.11, 5.21, 5.21, 5.22), and e) a second communication device (6.0, 6.1, 6.2) is arranged at a second coupling point in order to couple a communication signal into respectively out from the first and second conductor (5.01, 5.02) and/or the further first and second conductors (5.11, 5.21, 5.21, 5.22).