Which of the following is a correct guideline for extension cord usage?

Using only extension cords that are factory-assembled is crucial for ensuring safety and reliability. Factory-assembled extension cords are designed and tested to meet specific safety standards, which include considerations for wire gauge, insulation, and proper connectors. These cords are also built to handle the electrical loads they are rated for, reducing the risk of overheating and potential electrical fires.

In contrast, using any available extension cord can lead to serious safety hazards, as not all cords are suitable for the same applications or environments. Moreover, attempting to repair frayed cords or relying on unsafe practices undermines the safety protocols that are in place to protect individuals from electrical hazards. Using factory-assembled cords is a key guideline to follow, ensuring that extension cords are safe for use in any electrical work.