What characterizes coarse excess-current protection?

Coarse excess-current protection is characterized by its response time to fault currents, which often aligns with the requirement for a delayed reaction in order to coordinate with upstream devices in a protection scheme. Hence, the statement that it does not interrupt a fault current within 4 hours aligns with its function as a protection method that allows for selective coordination. This means that coarse protection devices are designed to operate only if a fault condition persists for an extended period, allowing other downstream protective devices to clear faults before it takes action. This ensures that the more sensitive devices can operate first to protect the circuit and prevent unnecessary outages or damage to equipment.

In this protective scheme, the intention is to minimize disruption while still providing necessary fault protection. The other options describe scenarios that do not accurately reflect the nature of coarse excess-current protection. For example, interrupting a fault current within 1 hour would imply a more immediate response, which is not characteristic of a coarse protection scheme. Additionally, the premise that it always operates before any other protective device is misleading, as coordination is essential in protection systems, resulting in the coarse device often acting last. Finally, the idea that it interrupts every current regardless of fault does not fit within the purpose of such protection, which is tailored to distinguish faults