S&C Mark V Instruction Sheet

S&C Instruction Sheet 711-590 11
Inspection Recommendations
Table 3� Allowable Resistance Values for S&C Mark V Circuit-Switcher, Vertical-Break And Integer Styles
kV Gaps
Allowable Resistance
In Microhms, Between Points
In Megohms,
Between Points
2-3, Interrupter
Open
1-4●
2-3, Interrupter Closed
1-2 3-4
4-7■
1-5 6-7
Continuous
Current Less
Than 400 A
Continuous
Current
Greater Than
400 A
34�5 1 30 600 200 15 15 130 40 40 –
46 1 30 600 200 15 15 140 40 40 –
69
1
30
600 200
15 15 160 40 40
–
2 1 000 333 208–312
115
1
30
600 200
15 15 220 40 40
–
2 1 000 333 208–312
138
1
30
600 200
15 15 230 40 40
–
2 1 000 333 208–312
3 1 500 500 312– 468
161
2
30
1 000 333
15 15 240 40 40
208–312
3 1 500 500 312– 468
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2 and 3 with the inter-
rupter closed. If the measurement exceeds the allowable
value indicated, measure the resistance between points2
and 3 with the interrupter open. If that measurement exceeds
the allowable value indicated, replace the interrupter.
Now, measure the resistance between points1 and 4
with the interrupter closed. If the measurement exceeds the
allowable value indicated, measure the resistance between
points1 and 2, and then measure the resistance between
points3 and 4. 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4 and 7 with
the interrupter closed. Subtract the value of resistance
measured between points2 and 3 with the interrupter
closed. If the difference exceeds the allowable value for
resistance between points 4 and 7, measure the resis-
tance between points6 and 7 and between points 1 and 5.
If either of those measurements exceeds the allowable
value, contact the nearest S&C Sales Ofce for assistance.
● Resistance between points 1 and 4 minus the actual resistance between
points 2 and 3 with the interrupter closed�
■ Resistance between points 4 and 7 minus the actual resistance between
points 2 and 3 with the interrupter closed�
⑤
①
②
③
④
⑥
⑦

S&C Mark V Specifications

General

Brand	S&C
Model	Mark V
Category	Switch
Language	English