What is the most important electrical safety practice before working inside a device?

Unplugging the device is crucial because it eliminates the risk of electrical shock while working inside. When a device is plugged in, there is a potential for live electricity to be present at various points within, which can lead to serious injury or even fatality if contact is made with electrified components. By disconnecting the power source, you ensure that the device is completely de-energized, thereby creating a safer workspace. This practice is a foundational aspect of electrical safety in any hands-on technical environment.

While protective eyewear is important for preventing injury from flying debris or accidental component damage, it does not address the immediate risk of electrical shock. Discharging static electricity is also vital to protect sensitive components from damage due to electrostatic discharge, but it does not mitigate the dangers associated with a device still being powered on. Therefore, ensuring the device is unplugged stands out as the most critical step in maintaining safety before any internal examinations or repairs.