Disconnecting the supply does not empty the equipment. Capacitors and batteries hold energy after everything is switched off.
This is the isolation that looks complete and is not. The switch is open, the lock is on, the meter reads zero at the incomer, and there is a charged capacitor inside the enclosure.
Two steps, and people do the first and skip the second. Controlling stored energy means discharging it by the approved method. Verifying means confirming afterwards that it is actually gone. A discharge you did not verify is the same class of claim as an absence-of-voltage test with an unproven meter: probably right, not established.
Check yourself: The supply is disconnected and the capacitor is out of circuit. Is it safe?
Answer: No. A disconnected capacitor is not automatically discharged.
A capacitor holds its charge until something discharges it. Disconnecting removes the source; it does not remove what is already stored, and an isolated capacitor can hold that charge for a long time.
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Written from the owner's poster for this lesson. Nothing added beyond what the poster states.
Written for Texas apprentices as free study material. The Texas apprentice licence is an application, not an exam (Occupations Code 1305.161), and nothing here counts as apprenticeship hours or continuing-education credit. VoltMark is not affiliated with, endorsed by, or sponsored by NFPA, PSI, TDLR, or any state or local licensing authority. Always follow your employer's safety programme and your supervising electrician.
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