R 408.10577 Control circuits; power circuits; components.

Rule 577. (1) Electrical wiring and equipment shall be in compliance with the requirements specified in General Industry Safety Standard Part 39 “Design Safety Standards for Electrical Systems,” as referenced in R 408.10509, except as otherwise required by these rules. (2) An electrical runway conductor system shall be of a type that is designed for use in exterior locations and shall be located so that the system does not come into contact with accumulated snow or water. (3) Cables shall be protected against damage that results from over-tensioning or from other causes. (4) Devices shall be included in the control system for the equipment which will provide protection against electrical overloads, 3-phase reversal, and phase failure. The control system shall have a separate method, which shall be independent of the direction control circuit, for breaking the power circuit if there is an emergency or malfunction. (5) Suspended or supported equipment shall have a control system that will require the operator of the equipment to follow predetermined procedures. (6) All of the following requirements apply to electrical protection devices: (a) On installations where the carriage does not have a stability factor of at least 4 against overturning, an electrical contact or contacts shall be provided and connected so that the operating devices for the suspended or supported equipment shall be operative only when the carriage is located and mechanically retained at an established operating point. (b) Overload protection shall be provided in the hoisting or suspension system to protect against the equipment operating in the "up" direction with a load of more than 125% of the rated load of the platform. (c) An automatic detector shall be provided for each suspension point which will interrupt power to all hoisting motors for travel in the "down" direction and which will apply the primary brakes if any suspension wire rope becomes slack. A continuous-pressure rigging-bypass switch that is designed for use during rigging is permitted. This switch shall only be used by authorized personnel during rigging. (d) Upper and lower directional switches that are designed to prevent the travel of suspended units beyond safe upward and downward levels shall be provided. (e) Emergency stop switches shall be provided on remote controlled, roof-powered platforms that are adjacent to each control station on the platform. (f) Cables that are in constant tension shall have overload devices which will prevent the tension in the cable from interfering with the load-limiting device or with the platform roll-limiting device. The setting of these devices shall be coordinated with other overload settings at the time the system is designed and shall be clearly indicated on or near the device. The device shall interrupt the equipment travel in the "down" direction.