ARTICLE 620 Elevators_ Dumbwaiters_ Escalators_ Moving Walks by liuqingyan



(D) Hoists and Monorail Hoists. Hoists and monorail                VII. Grounding
hoists and their trolleys that are not used as part of an          610.61 Grounding. All exposed non-current-carrying
overhead traveling crane shall not require individual motor        metal parts of cranes, monorail hoists, hoists, and
overload protection, provided the largest motor does not           accessories, including pendant controls, shall be
exceed 7lh hp and all motors are under manual control of           metallically joined together into a continuous electrical
the operator.                                                      conductor so that the entire crane or hoist will be grounded
                                                                   in accordance with Article 250. Moving parts, other than
VI. Control                                                        removable accessories, or attachments that have metal-to-
                                                                   metal bearing surfaces, shall be considered to be
610.51 Separate Controllers. Each motor shall be                   electrically connected to each other through bearing
provided with an individual controller unless otherwise            surfaces for grounding purposes. The trolley frame and
permitted in 610.51(A) or 61O.51(B).                               bridge frame shall not be considered as electrically
(A) Motions with More Than One Motor. Where two or                 grounded through the bridge and trolley wheels and its
more motors drive a single hoist, carriage, truck, or bridge,      respective tracks. A separate bonding conductor shall be
they shall be permitted to be controlled by a single               provided.
(B) Multiple Motion Controller. One controller shall be
permitted to be switched between motors, under the                                  ARTICLE 620
following conditions:                                                    Elevators, Dumbwaiters, Escalators,
(I) The controller has a horsepower rating that is not lower             Moving Walks, Wheelchair Lifts, and
    than the horsepower rating of the largest motor.                            Stairway Chair Lifts
(2) Only one motor is operated at one time.
610.53 Overcurrent Protection. Conductors of control               I. General
circuits shall be protected against overcurrent. Control
circuits shall be considered as protected by overcurrent           620.1 Scope. This article covers the installation of
devices that are rated or set at not more than 300 percent of      electrical equipment and wiring used in connection with
the ampacity of the control conductors, unless otherwise           elevators, dumbwaiters, escalators, moving walks,
permitted in 610.53(A) or 610.53(B).                               wheelchair lifts, and stairway chair lifts.
                                                                      FPN No.1: F,or further infonnation, see ASME/ANSI
(A) Taps to Control Transformers. Taps to control                     A17.1-2000, Safety Code for Elevators and Escalators.
transformers shall be considered as protected where the               FPN No.2: For further infonnation, see ASME/ANSI
secondary circuit is protected by a device rated or set at not        AI7.5-1996 (CSA B44.1-1996), Elevator and Escalator
more than 200 percent of the rated secondary current of the           Electrical Equipment Certification Standard.
transformer and not more than 200 percent of the ampacity          620.2 Definitions.
of the control circuit conductors.
                                                                   Control Room (for Elevator, Dumbwaiter). An enclosed
(B) Continuity of Power. Where the opening of the                  control space outside the hoistway, intended for full bodily
control circuit would create a hazard, as for example, the         entry, that contains the elevator motor controller. The room
control circuit of a hot metal crane, the control circuit          could also contain electrical and/or mechanical equipment
conductors shall be considered as being properly protected         used directly in connection with the elevator or dumbwaiter
by the branch-circuit overcurrent devices.                         but not the electric driving machine or the hydraulic
610.55 Limit Switch. A limit switch or other device shall          machine.
be provided to prevent the load block from passing the safe        Control Space (for Elevator, Dumbwaiter). A space
upper limit of travel of all hoisting mechanisms.                  inside or outside the hoistway, intended to be accessed with
610.57 Clearance. The dimension of the working space in            or without full bodily entry, that contains the elevator
the direction of access to live parts that are likely to require   motor controller. This space could also contain electrical
examination, adjustment, servicing, or maintenance while           and/or mechanical equipment used directly in connection
energized shall be a minimum of 750 mm (2lh ft). Where             with the elevator or dumbwaiter but not the electric driving
controls are enclosed in cabinets, the door(s) shall either        machine or the hydraulic machine.
open at least 90 degrees or be removable.                          Control System. The overall system governing the
                                                                   starting, stopping, direction of motion, acceleration, speed,
                                                                   and retardation of the moving member.

70-494                                                                                                2007 California Electrical Code

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