Wiring and equipment shall comply with subpart S of this part.
The voltage at pendant push-buttons shall not exceed 150 volts for a.c. and 300 volts for d.c.
Where multiple conductor cable is used with a suspended pushbutton station, the station must be supported in some satisfactory manner that will protect the electrical conductors against strain.
Pendant control boxes shall be constructed to prevent electrical shock and shall be clearly marked for identification of functions.
The control circuit voltage shall not exceed 600 volts for a.c. or d.c. current.
Electrical equipment shall be so located or enclosed that live parts will not be exposed to accidental contact under normal operating conditions.
Guards for live parts shall be substantial and so located that they cannot be accidently deformed so as to make contact with the live parts.
Electric equipment shall be protected from dirt, grease, oil, and moisture.
Cranes not equipped with spring-return controllers or momentary contact pushbuttons shall be provided with a device which will disconnect all motors from the line on failure of power and will not permit any motor to be restarted until the controller handle is brought to the "off" position, or a reset switch or button is operated.
The controller operating handle shall be located within convenient reach of the operator.
As far as practicable, the movement of each controller handle shall be in the same general directions as the resultant movements of the load.
Remote-operated cranes shall function so that if the control signal for any crane motion becomes ineffective the crane motion shall stop.
The control for the bridge and trolley travel shall be so located that the operator can readily face the direction of travel.
For floor-operated cranes, the controller or controllers if rope operated, shall automatically return to the "off" position when released by the operator.
Pushbuttons in pendant stations shall return to the "off" position when pressure is released by the crane operator.
Automatic cranes shall be so designed that all motions shall fail-safe if any malfunction of operation occurs.
Lever operated controllers shall be provided with a notch or latch which in the "off" position prevents the handle from being inadvertently moved to the "on" position. An "off" detent or spring return arrangement is acceptable.
Enclosures for resistors shall have openings to provide adequate ventilation, and shall be installed to prevent the accumulation of combustible matter too near to hot parts.
Provision shall be made to prevent broken parts or molten metal falling upon the operator or from the crane.
Resistor units shall be supported so as to be as free as possible from vibration.
The power supply to the runway conductors shall be controlled by a switch or circuit breaker located on a fixed structure, accessible from the floor, and arranged to be locked in the open position.
On floor-operated cranes, a switch or circuit breaker of the enclosed type, with provision for locking in the open position, shall be provided in the leads from the runway conductors. This disconnect shall be mounted on the bridge or footwalk near the runway collectors. One of the following types of floor-operated disconnects shall be provided:
Nonconductive rope attached to the main disconnect switch.
An undervoltage trip for the main circuit breaker operated by an emergency stop button in the pendant pushbutton in the pendant pushbutton station.
A main line contactor operated by a switch or pushbutton in the pendant pushbutton station.
The hoisting motion of all electric traveling cranes shall be provided with an overtravel limit switch in the hoisting direction.
All cranes using a lifting magnet shall have a magnet circuit switch of the enclosed type with provision for locking in the open position. Means for discharging the inductive load of the magnet shall be provided.
On cab-operated cranes a switch or circuit breaker of the enclosed type, with provision for locking in the open position, shall be provided in the leads from the runway conductors. A means of opening this switch or circuit breaker shall be located within easy reach of the operator.
Conductors of the open type mounted on the crane runway beams or overhead shall be so located or so guarded that persons entering or leaving the cab or crane footwalk normally could not come into contact with them.
If a service receptacle is provided in the cab or on the bridge of cab-operated cranes, it shall be a grounded three-prong type permanent receptacle, not exceeding 300 volts.