What happens if a recloser fails to detect a fault in the electrical system?

When a recloser fails to detect a fault in the electrical system, it leads to the situation where the system remains open, resulting in a disruption of service. This occurs because the recloser's primary function is to analyze the current flowing through the system and identify fault conditions. If it cannot sense the fault due to a malfunction or incorrect settings, it will not close the circuit to restore power. Consequently, the affected section of the system remains without power, necessitating manual intervention to reset or troubleshoot the issue and restore service.

In contrast, other options present scenarios that do not accurately reflect the outcome of a recloser failing to detect a fault. For example, while triggering an alarm for inspection is a proactive measure, it is not a standard response of a recloser failure—it does not reopen the system nor provide immediate service. Similarly, rerouting power is an advanced response typically managed by more complex systems rather than relying solely on a recloser, which specifically operates at the point of fault detection. Lastly, taking the entire grid offline is a measure of last resort, usually implemented by larger control systems and not directly resultant from an individual recloser's failure to detect a fault.