Screw Fastenings
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 11 Recommended Tightening Torques for Screw Connection
|
Threads |
Plastics |
Threaded welding pin |
Insert nut for insulation |
Main circuit |
Secondary connection |
General connection |
|---|---|---|---|---|---|---|
|
M3 |
0.1 |
– |
– |
– |
0.7 |
1.1 |
|
M4 |
0.25 |
– |
– |
– |
1.5 |
2.6 |
|
M5 |
0.5 |
– |
3.5 |
– |
2.5 |
5.0 |
|
M6 |
0.8 |
6.5 |
6.5 |
6.5 |
3.5 |
8.8 |
|
M8 |
1.8 |
15.0 |
15.0 |
17.0 |
– |
21.0 |
|
M10 |
3.5 |
27.0 |
32.0 |
35.0 |
– |
42.0 |
|
M12 |
6.0 |
– |
45.0 |
68.0 |
– |
70.0 |
|
M16 |
12.0 |
– |
110.0 |
135.0 |
– |
170.0 |
|
M20 |
– |
– |
220.0 |
– |
– |
330.0 |
The main circuit includes the below fastenings:
-
Copper busbar connections and fastening bolts.
-
Cable fastening bolts.
-
Fastening bolts for contact.
-
E/S and load-break switch, bolts for connection with the busbar.
-
For CT and VT torque values, refer to the instruction sheet.