Cal. Lab. Code § 7382

No person shall install or dismantle a tower crane, or increase the height of a crane, known in the construction trade as “jumping or climbing a crane,” without a safety representative of the crane manufacturer, distributor, or a representative of a licensed crane certifier being present on site for consultation during the procedure. The standards board shall adopt a regulation making failure to provide the designated safety representative a serious violation of a safety order. Local governmental entities may restrict the hours during which these procedures may be performed.