A source change over system having distributed electrical interlocking, the source change over system comprising: a plurality of switch disconnectors/circuit breakers (304, 306), interconnections amongst the plurality of switch disconnectors/circuit breakers (304, 306) by one or more communication channels, in each switch disconnector/circuit breaker (304, 306) an electrical interlock control mechanism adapted to implement a token exchange method, characterized in that an automatic transfer switch (ATS, 302) is provided for issuing control commands; the switch disconnectors/circuit breakers (304, 306) are communicatively coupled with the automatic transfer switch (ATS, 302) for tripping actuators for break operation based on the control commands; every switch disconnector/circuit breaker (304, 306) has a Human Machine Interface (HMI, 308, 312), a field bus communication interface (310, 314) and an input/output interface (318, 320), each for monitoring and controlling the respective switch disconnector/circuit breaker (304, 306) the communication channels amongst said switch disconnectors/circuit breakers (304, 306) comprise said input/output interfaces (318, 320), and wherein the plurality of switch disconnectors/circuit breakers are adapted to take decisions of token exchange based on: the switch disconnector/circuit breaker that intends to close the breaker requires to possess an electrical interlocking token therewith; the interlocking token is possessed by only one switch disconnector/circuit breaker at a time or the interlocking token is possessed by none of the switch disconnectors/ circuit breaker; if a switch disconnector/circuit breaker intends to close the breaker and does not possess the electrical interlocking token therewith a request is sent to other switch disconnectors/ circuit breakers to release the interlocking token thereto that requires the token for closing the breaker; and a switch disconnector/ circuit breaker releases the token to other switch disconnector/ circuit breaker if and only if the breaker of the releasing switch disconnector is in open and not in trip state and no other token request is pending. a plurality of switch disconnectors/circuit breakers (304, 306), interconnections amongst the plurality of switch disconnectors/circuit breakers (304, 306) by one or more communication channels, in each switch disconnector/circuit breaker (304, 306) an electrical interlock control mechanism adapted to implement a token exchange method, an automatic transfer switch (ATS, 302) is provided for issuing control commands; the switch disconnectors/circuit breakers (304, 306) are communicatively coupled with the automatic transfer switch (ATS, 302) for tripping actuators for break operation based on the control commands; every switch disconnector/circuit breaker (304, 306) has a Human Machine Interface (HMI, 308, 312), a field bus communication interface (310, 314) and an input/output interface (318, 320), each for monitoring and controlling the respective switch disconnector/circuit breaker (304, 306) the communication channels amongst said switch disconnectors/circuit breakers (304, 306) comprise said input/output interfaces (318, 320), and wherein the plurality of switch disconnectors/circuit breakers are adapted to take decisions of token exchange based on: the switch disconnector/circuit breaker that intends to close the breaker requires to possess an electrical interlocking token therewith; the interlocking token is possessed by only one switch disconnector/circuit breaker at a time or the interlocking token is possessed by none of the switch disconnectors/ circuit breaker; if a switch disconnector/circuit breaker intends to close the breaker and does not possess the electrical interlocking token therewith a request is sent to other switch disconnectors/ circuit breakers to release the interlocking token thereto that requires the token for closing the breaker; and a switch disconnector/ circuit breaker releases the token to other switch disconnector/ circuit breaker if and only if the breaker of the releasing switch disconnector is in open and not in trip state and no other token request is pending. the switch disconnector/circuit breaker that intends to close the breaker requires to possess an electrical interlocking token therewith; the interlocking token is possessed by only one switch disconnector/circuit breaker at a time or the interlocking token is possessed by none of the switch disconnectors/ circuit breaker; if a switch disconnector/circuit breaker intends to close the breaker and does not possess the electrical interlocking token therewith a request is sent to other switch disconnectors/ circuit breakers to release the interlocking token thereto that requires the token for closing the breaker; and a switch disconnector/ circuit breaker releases the token to other switch disconnector/ circuit breaker if and only if the breaker of the releasing switch disconnector is in open and not in trip state and no other token request is pending.