Velatia Ormazabal ormaset, Общее руководство по инструкции

Страница: 18 / 28

IG-049-EN version 02; 02/10/2017
18
Installation
General Instructions
ormaset
Kiosk-type prefabricated transformer substation
9.6.2. Operational earthing circuit (neutral)
The operational earthing circuit (neutral) connects the
neutral busbar of the low voltage distribution board to the
operational earthing switch box, which is located to the left
of the low voltage access door. This connection is made by
means of insulated 0.6/1 kV copper or 50 mm
2
aluminium
cable.
The low voltage board zero-sequence bar is not
connected to the protective earthing flatbar (metallic
parts).
Figure 9.7. Detail of the switch box for connecting the neutral
9.6.3. Exterior earthing circuit
The installer or final user must provide suitable safety
measures in order to avoid dangerous touch and step
voltage.
The installation project must include the section for
implementation of the earthing installation, along with
justification of its sizing.
Complementary Technical Instruction ITC-RAT 13, on
earthing installations, of the Regulation on technical
conditions and safety guarantees in high voltage electrical
installations (Royal Decree 337/2014) sets out the
requirements for this type of installation.
The conductors' braided wire cross-section, the terminals'
contact surface and tightening torques will be suitable
for a fault current delimited by network protections. It is
recommended that an external protective earthing circuit
of bare copper wire be used with a minimum cross-section
of 50 mm
2
.
Whenever it is not feasible to maintain the touch and
step voltages within the limits set out in Complementary
Technical Instruction ITC-RAT 13 of the Regulation on
technical conditions and safety guarantees in high voltage
electrical facilities (Royal Decree 337/2014), the owner of
the facility must implement at least one of the additional
safety measures envisaged in this instruction, in order to
reduce the risks to people and property.