Planning The Grid Connection (Ac); Important Safety Instructions; Residual Current Circuit Breaker; Integrated Residual Current Monitoring Unit - Delta M50A-260 Installation And Operation Manual

5.4

Planning the grid connection (AC)

Related topics
"7.8 Connecting the grid (AC)", page 76

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
PE L1 L2 L3
► 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
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 (e.g.
humidity). The tripping current must not, how-
ever, be less than the specified minimum tripping
current.
Installation and Operation Manual M50A_260 RPI503M260000 Product version L and M EU V1.3 EN 2023-08-14
125 A recommended
L3
L2
to the
L1
inverter
PE
≥300 mA
5 Planning the installation
Planning the grid connection (AC)

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 §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, Delta Electronics can order combined type 1+2 AC
surge protection devices.

5.4.5 Permissible grounding systems

Grounding system TN-S
Allowed Yes
TN-C TN-C-S TT IT
Yes Yes Yes Yes
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