What does Exception No. 3 allow concerning energized work?

The correct answer indicates that energized work can be permitted when it is infeasible to de-energize the equipment or system. This recognizes that there are certain situations in the electrical industry where turning off power is either impractical or impossible, such as when performing maintenance on critical systems that must remain operational for safety reasons or where disruption of service could result in severe consequences.

In such cases, work practices must still adhere to stringent safety protocols, including the use of personal protective equipment (PPE) and proper safety procedures, to mitigate risks associated with working on energized systems. Thus, while the preference and safest course of action is always to de-energize equipment, exceptions are made when de-energization can't be achieved without significant issues, ensuring that personnel can proceed safely with the work required.