26 S&C Instruction Sheet 662-510
Appendix A
Table 1. Ratings and Insulation Test Values
Rating, kV Withstand, kV
Nom. Max
① 60-Hz, RMS② Dc③④
Impulse (BIL)
14.4
25
25
17.0
27
●
29■
36
60
60
50
70
70
95
125
125
① Maximum voltage ratings are lower than the values listed when cur-
rent-limiting fuses are used. Consult the appropriate current-limiting
fuse manufacturer for complete fuse ratings.
② Ac withstand tests made on this equipment after shipment by S&C
should be conducted at no more than 0.75 times the values shown.
When making ac tests, the time duration for application of the test volt-
age should be limited to less than 10 seconds.
③ The column headed “Dc” is given as a reference only for those
making dc tests and represents values believed to be appropriate and
approxi mately equivalent to the corresponding power-frequency with-
stand test values specified for components of this voltage class. The
presence of this column in no way implies any requirement for a dc
withstand test on these components.
④ Dc withstand tests made on this equipment after shipment by S&C
should be conducted at no more than 0.75 times the values shown.
When making dc tests, the test voltage should be raised in discrete
steps—one minute per step.
● With fuses.
■ Without fuses.
Dielectric Testing
For the convenience of users who normally perform elec-
trical tests on system components such as pad-mounted
gear, appropriate withstand test values are given in Table 1.
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