28
S&C Instruction Sheet 695-510
Vista SD
Underground
Distribution
Switchgear Ratings
Table 4. Vista SD Switchgear Ratings
①
Voltage, kV
Amperes, RMS
System Class
Max
BIL
Main Bus
Continuous Current
Short-Circuit,
RMS, Sym.
15
(12)
17 .5
(12)
95
(75)
600
(630)
16 000
★
27
(24)
29
(24)
125
(125)
600
(630)
12 500
①
IEEE ratings are given first, with the IEC ratings
in parentheses .
★
12 500 amperes if fault interrupters are furnished
with optional 200-ampere bushing wells in lieu of
600-ampere bushings .
Ratings for S&C
Visi-Gap Load-
Interrupter Switches
Complete ratings for Visi-Gap load-interrupter switches are shown in Table 5. Besides the
load-dropping ratings shown, the switches are capable of interrupting transformer magnetizing
currents associated with the applicable loads as well as line-charging and cable-charging
currents typical for distribution systems of these voltage ratings. For applications involving
load currents with high harmonic content (such as rectifier load currents), refer to the nearest
S&C Sales Office. The duty-cycle fault-closing rating shown for the switch defines the ability
to close the switch into the
Closed
position the designated number of times against a three-
phase fault equal to the rated value, with the switch remaining operable and able to carry
and interrupt rated current.
Table 5. Vista-Gap Load-Interrupter Switch Ratings
Applicable
Standard
Freq.,
Hertz
Visi-Gap Load Interrupter Switches
Voltage, kV
Amperes
Nom.
Max
BIL
Continuous, Load
Dropping, and
Load Splitting
①
Momentary and
One-Second,
Short-Time
Withstand, RMS,
Symmetrical
Three-Time
Duty Cycle Fault
Making, RMS,
Symmetrical
②
IEEE
60
15
17 .5
95
600
16 000
16 000
27
29
125
600
16 000
16 000
IEC
50
12
12
75
630
16 000
16 000
24
24
125
630
16 000
16 000
①
Parallel or loop switching .
②
Applicable to fault closing into the
Closed
position .
Ratings for S&C
Visi-Gap Fault
Interrupters
Complete ratings for Visi-Gap fault interrupters are shown in Table 6. Besides the load-dropping
ratings shown, the fault interrupters are capable of interrupting transformer magnetizing
currents associated with the applicable load as well as line-charging and cable-charging
currents typical for distribution systems of these voltage ratings.
Table 6. Visi-Gap Fault Interrupter Ratings
Applicable
Standard
Freq.,
Hertz
Visi-Gap Fault Interrupters
Voltage, kV
Amperes
Nom.
Max
BIL
Continuous, Load Dropping,
and Load Splitting
①
Short-Circuit Interrupting,
RMS, Symmetrical
IEEE
60
15
17 .5
95
600
16 000
★
27
29
125
600
12 500
IEC
50
12
12
75
630
16 000
★
24
24
125
630
12 500
①
200 amperes if the fault interrupters are
furnished with optional 200-ampere bushing wells .
★
12 500 amperes if the fault interrupters are
furnished with optional 200-ampere bushing wells
in lieu of 600-ampere bushings .
Appendix B
