An electrical system having a master node, at least one slave node and a bus linked to both of the master node and the slave node is illustrated. The master node check whether a reception register of the slave node does not receives a new data for a first time period, and resets the slave node while the reception register of the slave node does not receives the new data for the first time period; and the slave node checks whether the reception register of the slave node does not receives the new data for a second time period, and resets the slave node itself while the reception register of the slave node does not receives the new data for the second time period. Therefore, the communication stability of the electrical system can be enhanced.