Siemens UL 1066 Operating Instructions Manual page 23

Recommendation for supporting the main conductors
The connecting bars of all poles should be braced together, line and load side separately.
Frame size
II
II fused
III
III fused
These distances are recommendations and are not construction specifications. All designs should be type tested according to 
ANSI C37.20.1 and ANSI C37.51 for design validation.
Rated breaking current
(kA)
50 / 65
85
100
200
85 /100
130 / 150
200
X
Dimension x
(mm)
250
200
200
200
200
100
200
(inch)
10
8
8
8
8
4
8
5 – 7