IG-245-EN version 05; 13/02/2020
41
General Instructions
mb
.m
Annex: recommended tightening torques
8. Annex: recommended tightening torques
The recommended torques for the electrical joints are as
follows:
Metric size
M10
M12
M16
M20
M30
Wrench size
17
19
24
30
46
Low voltage (LV)
Connection between nuts
-
15-20
-
70-100
250-300
Fastening the palms to the pin (stainless steel bolts)
25-35
40-60
-
-
-
Bolts at palm surface
25-35
40-70
100-150
-
-
Connections in LV busbars (steel nut and bolt).
45-60
65-85
95-130
-
-
Medium voltage (MV)
Fastening terminals to the medium voltage pin (brass pin and nuts
[*]
-
10-15
-
-
-
(*) The medium voltage terminals include three nuts, but only the two top can be handled. The purpose of the lower nut is to tighten the insulator gasket;
if it is loosened, it could cause leakage of the dielectric liquid.
Table 8.1.
Recommended torques for electrical joints [Nm]
The recommended torques for the mechanical joints are as
follows:
Metric size
Bolted joints strength
grade 8.8
M10
49
M12
86
Table 8.2.
Recommended torques for mechanical joints [Nm]
