What should you never do before working on electrical equipment?

Ensuring the circuit is de-energized is crucial before working on electrical equipment because it directly addresses safety risks associated with electrical shock and potential equipment damage. When you confirm that a circuit is not energized, you eliminate the immediate danger of electrical current, which can cause severe injury or fatality.

Testing the voltage, while important, should only be done after ensuring that the circuit is de-energized. Checking the ground connection is part of ensuring safety but does not inherently protect you from live circuits. Increasing the power supply would create additional hazards, especially if the equipment is being worked on and not isolated properly. Therefore, confirming that the circuit is de-energized is the most essential first step to safely handling any electrical work.