Ormazabal velatia mb.m Series, Общее руководство по инструкции

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IG-245-EN version 05; 13/02/2020
35
General Instructions
mb
.m
Installation
5.7. Earthing circuit connection
The
mb
.m transformer substation has an earthing bar to
protect all the components of the prefabricated substation:
• The metal frame of the mb .m.
The metal frame of the
mb
.m has an earthing bar for
M10, which the facility's earth must be connected to.
• Transformer neutral.
The transformer neutral is supplied by default
connected to the protection earthing bar using
0.6/1 kV copper cable with a 50 mm
2
insulated cross-
section.
• The medium voltage switchgear enclosure.
• The medium voltage switchgear system.
• The earth screen of the medium voltage cables.
• The transformer unit.
• The perimeter fence and the liquid retention tank,
where fitted.
• The frame, the enclosure and the low voltage switchgear,
where included.
Figure 5.20.
Example of earthing circuit in
mb
.m (subject to variations,
depending on the configuration and auxiliary services
installed)
The final user or installer should provide suitable safety
measures around the
mb
.m in order to prevent the risk of
touch and step voltage contacts.
5.7.1. Recommended exterior protective earth network
When installing the protective earthing electrode in the
mb .m, it is recommended to use a perimeter ring with a
cross-section that is equal to or above 30 mm
2
around the
mb .m at an approximate distance of 1 m relative to the
perimeter of the mb .m, and at a depth of 0.4 m.
This perimeter ring must be connected to the mb .m earthing
bar using a terminal and M10 bolt. When installing the mb .m
on a concrete slab (see section 5.3), it is recommended to
connect the perimeter ring to the slab's mesh.