Are disconnect switches or breaker isolation switches designed to open fault current?

Disconnect switches or breaker isolation switches are primarily designed to isolate sections of electrical circuits for maintenance or safety purposes, rather than to interrupt fault currents during operation. Their main function is to provide a visible break in the circuit, allowing workers to safely perform maintenance on equipment and ensure that no current is present in that section.

Unlike circuit breakers, which are specifically designed to detect and interrupt fault currents, disconnect switches do not have the capability to safely interrupt high fault currents without risk of damage or failure. When a fault occurs, the load and fault currents can be very high, and disconnect switches could fail if they were used to interrupt such currents. Therefore, the assertion that these switches are designed to open fault current is not accurate, reinforcing the conclusion that the statement is false. Understanding the specific purpose and limitations of these devices is crucial for linemen and apprentices working with electrical systems.