An electrical relay system comprising: a first relay having a first common contact configured to switch between a first normally closed contact and a first normally open contact according to energization of a coil; a second relay having a second common contact configured to switch between a second normally closed contact and a second normally open contact according to energization of a second coil, wherein the first common contact of the first relay is coupled to the second common contact of the second relay at a common node; a signal generator configured to inject a signal at the common node; first and second controllers in communication with one another, wherein the first controller is in further communication with the first coil for controlling the first relay to switch and the second controller is in further communication with the second coil for controlling the second relay to switch; a first detection circuit coupled to the first normally closed contact, wherein the first detection circuit is configured to detect the signal when the first common contact is switched to the first normally closed contact; and a second detection circuit coupled to the second normally closed contact of the second relay, wherein the second detection circuit is configured to detect the signal when the second common contact of the second relay is switched to the second normally closed contact of the second relay characterized in that the first controller is configured to switch the first relay before the second controller controls the second relay to switch and wherein the first controller is configured to control the signal generator to send a first pulse before the first relay is switched, a second pulse after the first relay is switched and a third pulse after the second relay is switched, and in that the electrical relay system is configured to determine a failure condition to be present if at least one of: the electrical relay system fails to detect the first pulse via the first detection circuit and the second detection circuit, the electrical relay system detects the second pulse via the first detection circuit, or fails to detect the second pulse via the second detection circuit, and the electrical relay system detects the third pulse via the first detection circuit or the second detection circuit. a first relay having a first common contact configured to switch between a first normally closed contact and a first normally open contact according to energization of a coil; a second relay having a second common contact configured to switch between a second normally closed contact and a second normally open contact according to energization of a second coil, wherein the first common contact of the first relay is coupled to the second common contact of the second relay at a common node; a signal generator configured to inject a signal at the common node; first and second controllers in communication with one another, wherein the first controller is in further communication with the first coil for controlling the first relay to switch and the second controller is in further communication with the second coil for controlling the second relay to switch; a first detection circuit coupled to the first normally closed contact, wherein the first detection circuit is configured to detect the signal when the first common contact is switched to the first normally closed contact; and a second detection circuit coupled to the second normally closed contact of the second relay, wherein the second detection circuit is configured to detect the signal when the second common contact of the second relay is switched to the second normally closed contact of the second relay characterized in that the first controller is configured to switch the first relay before the second controller controls the second relay to switch and wherein the first controller is configured to control the signal generator to send a first pulse before the first relay is switched, a second pulse after the first relay is switched and a third pulse after the second relay is switched, and in that the electrical relay system is configured to determine a failure condition to be present if at least one of: the electrical relay system fails to detect the first pulse via the first detection circuit and the second detection circuit, the electrical relay system detects the second pulse via the first detection circuit, or fails to detect the second pulse via the second detection circuit, and the electrical relay system detects the third pulse via the first detection circuit or the second detection circuit. the electrical relay system fails to detect the first pulse via the first detection circuit and the second detection circuit, the electrical relay system detects the second pulse via the first detection circuit, or fails to detect the second pulse via the second detection circuit, and the electrical relay system detects the third pulse via the first detection circuit or the second detection circuit.