Power Electronics SD750K, Hardware And Installation Manual

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POWER ELECTRONICS SD750K
TORQUE AND SCREW SIZING
15
TORQUE AND SCREW SIZING
The following table shows, broadly speaking, the recommended tightening torque for both mechanical and
electrical connections, applicable to all cabinets
[1, 2]:
SCREW SIZE RECOMMENDED TORQUE
METRIC (mm)
ENGLISH
(inches)
DIN (Nm) ASTM (ft*lb)
6,9 QUALITY [a] 8,8 QUALITY [a] A449 TYPE 1 [a] A325 TYPE 1 [a]
M3 1/8 1 1,3
-
-
M4 5/32 2,5 3
M5 3/16 4 6
M6 1/4 5 10 4
M8 5/16 20 25 9
M10 7/16 40 50 25
M12 1/2 60 70 38 50 – 58
M14 9/16 100 120 54 -
M16 5/8 150 210 75 99 – 120
[a] For
other qualities, follow the screw’s manufacturer guidelines.
CAUTION
For all screwing that hold a particular component such as a bus, contactor, etc. it will be necessary to
apply the tightening torque indicated by the manufacturer of the same component.
Screwing should be tightened correctly only when necessary, i.e. when the factory marks are not in place.
For small screws that do not have marks, the good electrical praxis will determine if it is loose.
1
Power Electronics recommends the use of Zinc Steel quality 8.8 bolts for internal connections in general, DC and
earth connections included.
2
Power Electronics recommends the use of A2-70 stainless bolts for external connections in general, AC connections
included.