Conductors

DOE-HDBK-1092-2004

cannot under any conditions exceed 8 mA, or for dc voltage if the current cannot, under any

circumstances, exceed 30 mA.

6.3.2.2 CONDUCTORS

Hoistway door conductors from the door interlocks to the hoistway riser shall be flame retardant,

suitable for a temperature of at least 200C, and Type SF or equivalent. See NEC Table 400.4

of the NEC for approved types of elevator cables and Note 5 to NEC Table 400.4 concerning

special requirements for traveling control and signal cables. Operating control and signal cable

conductors may be as small as #24 AWG. Traveling cable conductors must be #20 AWG or

larger.

6.3.2.3 DISCONNECTING MEANS

The disconnecting means requirements for elevators and escalators are both specific and

extensive, requiring careful study of the codes and installation plans during design, acceptance

testing, and routine inspections. Some of the basic requirements of NEC 620.51 are the

following:

1. There shall be a single means of disconnecting all ungrounded conductors to the main

power supply of each unit.

2. A single elevator or escalator, with multiple driving machines, shall have one disconnecting

means to disconnect the motors and control valve operating magnets.

3. When there is more than one driving machine in a machine room, the disconnecting means

shall be labeled.

4. The disconnect shall be a fused motor circuit switch or circuit breaker capable of being

locked open.

5. The disconnect shall not be provided with a means of being operated from a remote

location.

6. A circuit breaker disconnecting means shall not be opened automatically by a fire alarm

system, except as allowed by NEC.

7. The within-sight rule applies to all elevator equipment disconnects. Specific locations are

given for elevators with or without field control.

8. The disconnecting means shall be installed in a location that is readily accessible to only

qualified persons.

When power from more than one source is used for single- or multiple-car installations, a

separate disconnect should be provided for each source. These disconnects should be in sight

of the equipment supplied, and warning signs should be placed on or adjacent to the disconnect

to read. For example, "Warning: Parts of the control panel are not deenergized by this switch."

Lighting circuits for each elevator require a disconnect switch in the equipment room labeled for

the car it serves and lockable in the open position.

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