Standard Tightening Torques
The elastic washers placed on the external sides of the connections and busbars help ensure for distribution of stress induced by the screw torque.
Table 1 Recommended Tightening Torques for Screw Connection
|
Threads |
Plastics |
Threaded welding pin |
Insert nut for insulation |
Main circuit |
Secondary connection |
Switchgear |
|||
|---|---|---|---|---|---|---|---|---|---|
|
– |
– |
Not lubricated |
Not lubricated |
Lubricated |
Not lubricated |
Lubricated |
Not lubricated |
Not lubricated |
Lubricated |
|
M3 |
– |
– |
– |
– |
– |
– |
2 |
1.1 |
– |
|
M4 |
1 |
– |
– |
– |
– |
– |
3 |
2.6 |
– |
|
M5 |
1.7 |
– |
3.5 |
– |
– |
– |
5.9 |
5 |
– |
|
M6 |
3 |
6.5 |
6.5 |
– |
10.5 |
– |
10 |
8.8 |
– |
|
M8 |
7 |
15 |
15 |
– |
26 |
– |
– |
21 |
– |
|
M10 |
12 |
27 |
32 |
– |
50 |
– |
– |
42 |
– |
|
M12 |
– |
– |
45 |
– |
86 |
– |
– |
70 |
– |
|
M16 |
– |
– |
110 |
44 |
200 |
80 |
– |
135 |
80 |
|
M20 |
– |
– |
220 |
88 |
300 |
120 |
– |
300 |
120 |
|
M24 |
– |
– |
295 |
118 |
– |
– |
– |
500 |
232 |
The main circuit includes the below fastenings the below:
-
Copper busbar connections and fastening bolts.
-
Cable fastening bolts.
-
Fastening bolts for contact.
-
Bolts for the CT and copper busbar connection.
-
E/S and load-break switch, bolts for connection with the busbar.