ABB ZS1 Instruction Manual page 36

Figure 5/13: Top mounted box with voltage transformers for busbar
metering. The figure (non-standard equipment) shows
the arrangement in panels without the busbar bushing
plate 28 (observe the notes in section 5.5.1).
28.3 Partitioning (non-standard; equipment on request)
79 Top mounted box with voltage transformer
79.1 Intermediate box
79.2 Conductor tube
79.3 Reducer ring
ABB Power Distribution
79
79.2
28.3
79.3 79.1
37