General Information

  • Table D6 - Recommended tightening torques for wire-binding screws, connectors with slotted screws and connectors for external drive wrenches.
  • Table D7 - Recommended tightening torques.

Table D6

Type of Connection Wire size
(AWG or kcmil)
Tightening Torque
(N•m)
Wire-binding screws 14-10 1.4
Connectors with slotted screws
(Slot width - 1.2 mm or less and slot length - 6.4 mm or less)
30-10 2.3
8 2.8
6-4 4.0
3 4.0
2 4.5
Connectors with slotted screws
(Slot width over 1.2 mm and slot length over 6.4 mm)
30-10 4.0
8 4.5
6-4 5.1
3 5.6
2 5.6
1 5.6
1/0 - 2/0 5.6
3/0 - 4/0 5.6
250 - 350 5.6
400 5.6
500 5.6
600 - 750 5.6
800 - 1000 5.6
Connectors for hexagonal head - External drive wrench (split-bold connectors) 30-10 9.0
8 9.0
6-4 18.6
3 31.1
2 31.1
1 31.1
1/0 - 2/0 43.5
3/0 - 4/0 56.5
250 - 350 73.4
400 93.2
500 93.2
600 - 750 113.0
800 - 1000 124.3
1250 - 2000 124.3
Connectors for hexagonal head - External drive wrench (other connectors) 30-10 8.5
8 8.5
6-4 12.4
3 16.9
2 16.9
1 16.9
1/0 - 2/0 20.3
3/0 - 4/0 28.2
250 - 350 36.7
400 36.7
500 42.4
600 - 750 42.4
800 - 1000 56.5
1250 - 2000 67.8

Table D7

Usage Connection Type and Size Tightening Torque (N•m)
Screws with recessed allen or square drives Socket (across flats)
mm (inches)
 
3.2 (1/8) 5.1
4.0 (5/32) 11.3
4.8 (3/16) 13.6
5.6 (7/32) 16.9
6.4 (1/4) 22.6
7.9 (5/16) 31.1
9.5 (3/8) 42.4
12.7 (1/2) 56.5
14.3 (9/16) 67.8
Connecting hardware Screw or bolt metric (SAE)  
No. 8 or smaller 2
No. 10 3
M6 (1/4) 8
5/16 15
M10 (3/8) 26
7/16 41
M12 (1/2) 54
9/16, 5/8, or larger 75
Slotted head screws smaller than No. 10 intended for use with No. 8 AWG or smaller conductors Slot width of screw less than 1.2mm (3/64 inch)
Slot length mm (inches)
 
<4 (<5/32) 7
4 (5/32) 7
4.8 (3/16) 7
5.6 (7/32) 7
6.4 (1/4) 9
Slot width of screw 1.2mm (3/64 inch) and larger
Slot length mm (inches)
41
< 4 (< 5/32) 9
4 (5/32) 12
4.8 (3/16) 12
5.6 (7/32) 12
6.4 (1/4) 12
7.1 (9/32) 12
> 7.1 (> 9/32) 20