Design Specifications

DOE-HDBK-1092-98

All elevators are required to be constructed, installed, and maintained in accordance with ANSI/

ASME A17.1. Reference standards include NFPA 70 (NEC) for the electrical equipment wiring and

NFPA 101 (Life Safety Code), Chapter 6, Features of Fire Protection, and Chapter 7, Building

Service and Fire Protection Equipment. These standards reflect the interrelated roles of electrical

design, maintenance, and fire protection in the electrical safety process.

6.3.2 DESIGN SPECIFICATIONS

The electrical designer shall provide for the installation requirements of Article 620 of the NEC as

well as the ANSI/ASME A17.1 requirements of Sections 102, 210, and 211 for signaling, automatic

fire protection, and emergency power as required. The manufacturer shall provide the required fire

service key switches, audible alarm devices, and internal wiring up to the terminal strips in the

elevator control panel.

6.3.2.1 VOLTAGE AND CURRENT LIMITATIONS

There shall be a 300-V limitation on all operating control and signal circuits and related equipment,

including door operators. Exceptions are permitted for 25 to 60 Hz ac if the current 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 Table 400-4 of the NEC

for approved types of elevator cables and Note 5 to 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. (See NEC Sections 620-11

and 12).

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 Section 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 per NEC Section 620-51 and 29 CFR 1910.303(f).

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

open.

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