S&C Instruction Sheet 665-506
15
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 the table
below:
RATINGS AND INSULATION TEST VALUES
Voltage Rating, kV
Test Voltage Withstand, kV
Nom
Max
1
60-Hertz, RMS
2
Dc
34
Impulse (BIL)
14 .4
25
25
17 .0
27
f
29
l
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 voltage 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 withstand
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 .
f
With S&C SME-20 or SME-4Z Power Fuses .
l
With Fault Fiter Electronic Power Fuses or without fuses .
