S&C PMH - Fusing; Assembling the Fuse

S&C Instruction Sheet 662-505 15
Dielectric Testing
For the convenience of users who normally perform
electrical tests on system components such as
pad-mounted gear, appropriate withstand test values are
given in Table 1.
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
current-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
approximately 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.