A switch assembly, which is part of a chain of switch assemblies, includes a communication unit (CU) configured to receive, from an external controller, a fire command to activate a detonator, a voltage measuring unit configured to locally measure a voltage (V) at the switch assembly after receiving the fire command to activate the detonator, a computing core (CC) configured to locally make a decision whether or not to activate the detonator, after receiving the fire command to activate the detonator and after measuring the voltage (V), based on whether or not the measured voltage (V) at the switch assembly is larger than a threshold value.