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Installation and Operation Manual M125HV EU V3 EN 2021-07-12
5 Planning the installation
Planning the grid connection (AC)
5.4
Planning the grid connection (AC)
Related topics
“6.7 Connect the mains (AC) and solar modules (DC)”,
page 73
5.4.1 Important safety instructions
► Always follow the specific regulations of your country or
region.
► Always follow the specific regulations of your energy pro
-
vider.
►
Install all the stipulated safety and protective devices (such
as automatic circuit breakers and/or surge protection devic-
es).
►
Protect the inverter with a suitable upstream circuit breaker:
Upstream circuit breaker
160 A
PE
L1
L3
L2
L1
L2
L3
PE
to the
inverter
►
Selection of the protective devices for the grid cables to
the transformer of the grid feed-in point: Always take into
account the impedance between the PE of the inverter and
the system and/or operational ground of the distribution
network. This applies in particular for IT networks.
5.4.2 Residual current circuit breaker
Due to its design, the inverter cannot supply the grid with DC
residual current. This means that the inverter meets the require-
ments of DIN VDE 0100-712.
Possible error events were assessed by Delta in accordance with
the current installation standards. The assessments showed that
no hazards arise from operating the inverter in combination with
an upstream, type A residual current circuit breaker (FI circuit
breaker, RCD). There is no need to use a type B residual current
circuit breaker.
Minimum tripping current of the type A residual
current circuit breaker
≥300 mA
The required tripping current of the residual cur-
rent circuit breaker depends first and foremost on
the quality of the solar modules, the size of the
PV system, and the ambient conditions example,
humidity). The tripping current must not, how-
ever, be less than the specified minimum tripping
current.
5.4.3 Integrated residual current monitoring unit
The integrated, universal current-sensitive residual current mon-
itoring unit (RCMU) is certified in accordance with VDE 0126
1-1:2013-08, Section 6.6.2.
5.4.4 AC surge protection devices
The inverter is equipped with type-2 AC surge protection devices.
Replacements can be ordered from Delta Electronics.
Alternatively, type-1 AC surge protection devices can be used.
The accessories required for connection are included in the deliv-
ery. The type-1 AC surge protection devices themselves are
not
included in the scope of delivery.
5.4.5 Permissible grounding systems
Grounding system
TN-S
TN-C
TN-C-S
TT
IT
Allowed
Yes
Yes
Yes
No
Yes
