Safety relays operate differently from general power relays. For example, if a Normally-open Form-A contact is closed and welded, a general power relay will not allow the Normally-closed Form-B contact to remain open. This is a very dangerous condition, and therefore a normal power relay cannot be used as it can cause danger to the operator due to insufficient safety measures. This type of circuit requires a physical mechanism to detect contact welding, thereby triggering the system to an emergency shut-off condition. Hence, the usage of a safety relay is ideal in this circuit to avoid any hazardous state.