PART XXVI ELECTRICAL OPERATIONS — Isolating devices
495
(1) An isolating device used to provide a safety protection guarantee shall provide for visual verification of the opening of an isolation point.
495(2)
A lockable isolating device shall be locked in the position or condition required to protect a worker before work commences under a safety protection guarantee.
495(3)
A distinctive "DO NOT OPERATE" tag shall be placed securely on an isolating device used for a safety protection guarantee.
Not legal advice. Verify the cited article against the signed agreement.