IG-049-EN version 02; 02/10/2017
17
General Instructions
ormaset
Kiosk-type prefabricated transformer substation
Installation
9.5. Access point for medium voltage and low voltage cables
ormaset
has holes pre-punched for the medium voltage
and low voltage cables and the external earthing circuit.
For the medium voltage cable input and output,
ormaset
has three pre-punched holes measuring 150 mm in
diameter, located in the buried part of the enclosure, in the
area where the medium voltage functions are housed.
For the low voltage cable output,
ormaset
has eight pre-
punched holes measuring 110 mm in diameter, located in
the buried part of the enclosure, where the low voltage
boards are housed.
The closure of these holes is a concrete shell measuring
about 10 mm thick.
Drilling of holes for feeding cables through them
1.
Break the hole closure by striking it with a hammer.
Tool:
hammer
2.
Seal the used holes to prevent water from entering
using any type of quality flexible sealant.
Tool:
Quality flexible sealant
1
Access for low voltage cables
2
Access for medium voltage cables
Figure 9.5.
Detail of
ormaset
cable access in enclosure
9.6. Earth connection
ormaset
has two internal earthing circuits to facilitate the
connection of the different elements to the earthing circuit
external to the transformer substation.
• Protective earthing circuit (metallic parts).
• Operational earthing circuit (neutral).
9.6.1. Protective earthing circuit (metallic parts)
The protective earthing circuit (metallic parts) includes
the earthing of the enclosures of the different electrical
equipment as well as the concrete enclosure reinforcement:
1.
Medium voltage functions.
2.
Transformer.
3.
Low voltage boards and other metallic elements
present in the installation.
4.
Concrete enclosure reinforcement (body and roof are
interconnected using a copper wire).
5.
Metallic parts.
The earthing flatbar is connected to the protective switch
box (metallic parts) that is located to the right of
ormaset
's
low voltage access door, using a 50 mm
2
bare copper
connector. This box is connected to the external earthing
circuit. Access for the external earthing cables is made using
two pre-punched holes measuring 20 mm in diameter.
Figure 9.6.
Detail of protective earthing connection (metallic parts).
Summary of Contents for Ormazabal ormaset
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