No person, firm, corporation or association shall, individually or through an agent or employee, or as an agent or employee, operate any crane, derrick, power shovel, drilling rig, hoisting equipment, or similar apparatus, any part of which is capable of vertical, lateral or swinging motion, unless there is posted and maintained in plain view of the operator thereof, a durable warning sign legible at twelve (12) feet, reading:
"Unlawful to operate this equipment within six feet of high voltage lines."
Each day's failure to post or maintain such signs shall constitute a separate violation.
Laws 1963, c. 118, § 3, emerg. eff. May 31, 1963.