S&C Mark V Instruction Sheet

12 S&C Instruction Sheet 711-590
Inspection Recommendations
Table 4� Allowable Resistance Values For S&C Mark V Circuit-Switcher, Center-Break Style
kV
Cont�
Current,
Amperes
Gaps
Allowable Resistance
In Microhms, Between Points
In Megohms,
Between
Points 5-6,
Interrupter
Open
4-7●
5-6, Interrupter Closed
1-2 3-4 4-5 6-7
7-8■
8-9
Continuous
Current
Less Than
400 A
Continuous
Current
Greater Than
400 A
230
1 600
3 30 1 500 500 30 30 15 15
165
30 312– 468
2 000 130
345
1 600
3 30 1 500 500 30 30 15 15 225 30 312– 468
2 000
⑤
①
②
③
④
DANGER
De-energize and ground the circuit-switcher at all six
terminals before making resistance measurements�
Follow all applicable safety procedures�
Failure to de-energize and ground the circuit-
switcher before making resistance measurements
can result in serious injury or death�
Interrupter
Measure the resistance between points5 and 6 with the inter-
rupter closed. If the measurement exceeds the allowable
value indicated, measure the resistance between points5
and 6 with the interrupter open . If that measurement exceeds
the allowable value indicated, replace the interrupter.
Now, measure the resistance between points 4 and 7
with the interrupter closed. If the measurement exceeds the
allowable value indicated, measure the resistance between
points 4 and 5, and then measure the resistance between
points 6 and 7. If either of those measurements exceeds
the allowable value, disassemble the appropriate bolted
connection, clean the surfaces, reapply an appropriate
contact lubricant, and reassemble the connection.
Disconnect
Measure the resistance between points 7 and 8 with
the interrupter closed. Subtract the value of resistance
measured between points 5 and 6 with the interrupter
closed. If the difference exceeds the allowable value for
resistance between points7 and 8, measure the resistance
between points 8 and 9, between points1 and 2, and between
points 3 and 4. If any of those measurements exceeds the
allowable value, contact the nearest S&C Sales Ofce for
assistance.
● Resistance between points 4 and 7 minus the actual measured
resistance between points 5 and 6 with the interrupter closed�
■ Resistance between points 7 and 8 minus the actual measured
resistance between points 5 and 6 with the interrupter closed�
⑥
⑦
⑧
⑨

S&C Mark V Specifications

General

Brand	S&C
Model	Mark V
Category	Switch
Language	English