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GENERAL INSTRUCTIONS FOR PREFORMA PF-4 / 5
ASSEMBLY AND USE OF PREFABRICATED PRIVATE
STATIONS (LV METERING)
IG-138-FR
version 02
02.10.2007
Page 10 of 28
1.3.5. LV switchgear
The PREFORMA PF substations can take prewired TGBT boards or simplified TGBT boards
including at least one master circuit-breaker containing one visible breaking.
The TGBT are prewired according to the guidelines of standard NFC15-100.
The equipment will be dimensioned according to the transformer power and the LV neutral
regime used.
1.3.6. LV connection between Transformer and TGBT
The cables used and supplied with the substation will be sized according to the power of the
transformer, the neutral system and the boundary conditions of the installation (installation
method, harmonic rate, voltage drops, risks of explosion, fire, reference temperature, type of
cable).
Each cable includes a functional marking on each end.
The curvature radii will be adhered to, i.e. 10 to 12 times the cable diameter.
1.3.7. Connection of the LV Network
The connections are made by the principal and must comply with the provisions of
NFC13-100 and NFC15-100.
The "knock-out" holes for cable entry are placed in an inclined plane, which makes it possible
to limit the height of the pit while allowing for the curvature radius of the cables.
1.3.8. Auxiliary Circuits
An auxiliary circuit supply board may be provided and its sizing will be in accordance with the
short-circuit powers of the transformers, the LV neutral regimes and the type of tripping coils
(emission or lack of voltage).
The board will supply:
The coils associated with the transformer's DGPT2.
The internal lighting and safety lighting.
The Fault Detector.
The 2P+T 16 A socket.
N.B. :
Use a sledgehammer and a stone chisel to knock out the entry holes.
