AC or 250-volt DC circuits. All such switches shall be capable of
satisfactorily withstanding a life test of at least 10,000 operations with
rated current flowing in the switch contacts. The switches shall be
capable of continuously carrying 20 amperes without exceeding a temperature
rise of 30 degrees C. The single-break inductive load interrupting rating
of switches shall be not less than 1.5 amperes for 125 volts DC or 10
amperes for 115 volts AC.
2.5.11.2
Escutcheons and Nameplates
Each control switch shall be provided with an escutcheon clearly marked to
show each operating position. The switch identifications shall be engraved
on the escutcheon plates or on separate nameplates. The escutcheon and
nameplate markings shall be subject to approval.
2.5.11.3
Switch Features
a. Control and instrument switches shall be suitable for the intended
use and shall have the features shown on the schematic diagrams and
switch development drawings. The switches shall have modern handles or
keys of pistol grip, oval, round notched or knurled type, and shall be
black color unless otherwise specified.
b. Control switches for electrically-operated circuit breakers shall
be 3 position momentary-contact type with spring return to neutral
position, and shall have modern-black, heavy duty pistol grip handles.
Circuit breaker control switches shall have mechanical operation
indicators to show the last manual operation of the switches, and shall
have slip contacts when so indicated or required.
c. Instrument and meter transfer switches and selector switches shall
be the maintained-contact type with the required number of positions,
and shall have round notched or knurled handles. Ammeter switches
shall not open the secondary circuits of current transformers at any
time. Instrument switches for potential selection shall have oval
handles.
2.5.12
Indicating Lamp Assemblies
Indicating lamp assemblies shall be of the switchboard type, insulated for
125-volt DC service, with appropriately colored caps and integrally mounted
resistors for nominal 125-volt DC service (140 volts maximum). Lamps shall
be long-life low-wattage type replaceable from the front of the panels and
any special tools required for lamp replacement shall be furnished. Color
caps shall be made of transparent or translucent material which will not be
softened by the heat from the lamps. Insofar as practicable, all color
caps shall be similar and interchangeable, and all lamps shall be of the
same type and rating.
2.5.13
2.5.13.1
General
Electrical indicating instruments shall conform to the applicable
requirements of ANSI C39.1 and the accuracy rating shall be within 1
percent of full-scale value. The instruments shall be back-connected
semiflush mounting. Instruments shall have white dials, circular scales,
black scale markings, and black tapered antiparallax pointers. Instrument
cases shall be dust tight with shadowproof covers and anti-glare windows.
SECTION 16404A
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