SMA SMC 5000 Installation

Sunny Mini Central 5000/6000
Central inverter for homogeneous PV-plants

Installation Guide Version 1.2 SMC50_60-11:SE2006

IME-SMC50-60

SMA Technologie AG Explanation of Symbols used in this Document

Explanation of Symbols used in this Document

This symbol indicates information that is essential for a trouble-free
and safe operation of the product. Please read these sections care­fully in order to avoid any damages of the equipment and for op­timal personal protection.

This symbol indicates information that is required for the optimal operation of
the product. Read these sections carefully in order to ensure an optimal ope­ration of the product and all its features.

This symbol indicates an example.

Installation Guide SMC50_60-11:SE2006 Page 3

Legal Restrictions SMA Technologie AG

Liability exclusion

The information contained in this documentation are the property of SMA Technologie AG. No part of this
documentation may be published without written permission from SMA Technologie AG. A reproduction for
internal purposes for the evaluation of the product or an appropriate application is permitted and does not
require authorization.

All information are based on our "General Terms and Conditions of Delivery of SMA Technologie AG”.
The content of this documentation is reviewed continuously and adjusted, if necessary. SMA Technologie
AG provides this documentation without exclusion of deviations and without warranty of completeness. You
will find the current version on the Internet at www.SMA.de or can obtain it via the usual sales channels.
Warranty or liability claims for all kinds are excluded in case of damages due to:

• Inappropriate use of the product

• Operation of the product in an improper environment

• Operation of the product without considering the relevant safety regulations

• Non-fulfillment of the warnings or safety instructions described in the documentation for the product

• Operation of the product under faulty conditions concerning security and protection

• Arbitrary changing of the product or the provided software

• Failure of the product due to interference of connected or contiguous devices out of legal limit values

• Disasters and force majeure

Software Licensing

The use of the provided software by SMA Technologie AG is subject to the following conditions:
The software may be reproduced for internal purposes and installed on any number of computers. Provided
source codes can be changed and adjusted on the company’s own authority according to the internal
purpose. Driver may be ported to other operating systems as well. No part of the source codes may be
published without written permission of SMA Technologie AG. Sublicensing of the software is not
acceptable.

Liability limitation: SMA Technologie AG disclaims liability for any direct or indirect consequential damages
arising from the use of the software produced by SMA Technologie AG. The same applies for the provision
and/or non-provision of support.

Provided software not produced by SMA Technologie AG is subject to the respective licensing and liability
agreements of the manufacturer.

Trademarks

All brand and product names used herein are trademarks or registered trademarks of their respective
holders, although they may not be specifically designated as such.

SMA Technologie AG
Hannoversche Strasse 1-5
34266 Niestetal
Germany
Tel. [phone] – 0
Fax [phone] – 100

www.SMA.de

E-Mail: [e-mail]

© 2005 SMA Technologie AG. All rights reserved.

Page 4 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Table of Contents

Table of Contents

1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Device Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

3.2 External Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

3.2.1 OptiCool Temperature Management . . . . . . . . . . . . . . . .13

4 Requirements for the Installation . . . . . . . . . . . . . . . . 15

4.1 Requirements: Mounting Place . . . . . . . . . . . . . . . . . . . . . . . .15

4.2 Requirements: PV-Modules. . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.3 String sizing of Sunny Mini Central PV plants . . . . . . . . . . . . .18

4.4 Requirements: Grid 230 V (AC) . . . . . . . . . . . . . . . . . . . . . . .18

5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

5.1 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.2 Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

5.3 Reverse Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

5.4 Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

6 Opening and Closing the Sunny Mini Central . . . . . . 35

6.1 Opening the Sunny Mini Central . . . . . . . . . . . . . . . . . . . . . .35

6.2 Closing the Sunny Mini Central . . . . . . . . . . . . . . . . . . . . . . .35

7 Technical Documentation . . . . . . . . . . . . . . . . . . . . . 37

7.1 Sunny Mini Central 5000. . . . . . . . . . . . . . . . . . . . . . . . . . . .37

7.1.1 Data PV Generator Connection . . . . . . . . . . . . . . . . . . . .37

7.1.2 Data Grid Connection. . . . . . . . . . . . . . . . . . . . . . . . . . .37

7.2 Sunny Mini Central 6000. . . . . . . . . . . . . . . . . . . . . . . . . . . .38

7.2.1 Data PV Generator Connection . . . . . . . . . . . . . . . . . . . .38

7.2.2 Data Grid Connection. . . . . . . . . . . . . . . . . . . . . . . . . . .38

7.3 Description of Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

7.4 Sunny Mini Central Operating Parameters . . . . . . . . . . . . . . .40

8 Checking the heat dissipation . . . . . . . . . . . . . . . . . . 43

8.1 Cleaning the fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

8.2 Testing the fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

8.3 Cleaning the Fins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

9 Exchanging Varistors . . . . . . . . . . . . . . . . . . . . . . . . 47

10 Sizing of a Circuit Breaker . . . . . . . . . . . . . . . . . . . . 51

11 Contact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Installation Guide SMC50_60-11:SE2006 Page 5

SMA Technologie AG

Page 6 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Introduction

1 Introduction

The installation of the Sunny Mini Central may only be done by
qualified technicians. The installer must be approved by the utility
company. Please read the installation guide carefully before you
begin with the installation. The installation of utility interactive
power sources must be compliant with all applicable regulations of
the utility company and with all applicable regulations and
standards.

The Sunny Mini Central 5000/6000 is equipped with the SMA grid guard. This
is a type of independent disconnection device. It ensures that the Sunny Mini
Central 5000/6000 complies with the VDEW (Verband der
Elektrizitätswirtschaft – German Electricity Industry Association) regulations for
the connection and parallel operation of electrical power units to the low­voltage grid of the electricity supply company and with DIN VDE 0126 (4.99)
which is a part of these regulations.

This installation manual is intended solely for qualified electricians. Its aim is to help
install and set up SMA Sunny Mini Central 5000/6000 inverters quickly and
correctly.

For detailed information on troubleshooting and on how to use the Sunny Mini
Central 5000/6000, including information about the different communication
options, please see the operating instructions.

The „Sunny Design“ tool will help to dimension and check the size of your strings with
respect to the inverter you intend to use. Further information about „Sunny Design“
is available at www.SMA.dSunny Mini CentralSunny Mini Centrale.

If you require further information, please call the Sunny Mini Central hotline on the
following number:

[phone] - 499

Installation Guide SMC50_60-11:SE2006 Page 7

Introduction SMA Technologie AG

Page 8 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Safety Instructions

2 Safety Instructions

Check your plant configuration and the
string sizing with „Sunny Design“ (avail­able at www.SMA.de) or with the Sunny
Mini Central Hotline before you start with
the installation. Exceeding the specifica­tions with the input voltage will destroy

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Work on the Sunny Mini Central with the lid removed must be
carried out by a qualified electrician. Hazardous and even lethal
voltages can be encountered within the enclosure. Before working
on the Sunny Mini Central with the lid removed, the AC and DC
voltages MUST be disconnected from the Sunny Mini Central and it
must be sure that all capacitors are discharged.

the Sunny Mini Central. Overvoltage on
the DC side can even cause dangerous ex­plosions of the Sunny Mini Centrals input
capacitors and explosions of the electro­lytes coming from the exploded capaci­tors.

The Sunny Mini Central must be disconnected from the mains and
precautions must be taken to prevent the grid being reconnected.
In addition, the connections to the PV generator must be
disconnected.

After isolating the AC and DC voltage you must wait approx. 30
minutes for the capacitors in the Sunny Mini Central to discharge.
Only then is it safe to open the unit by removing the lid. You must
also make sure that no voltage is present in the device.

The electronics inside your Sunny Mini Central 5000/6000 is
vulnerable in terms of electrostatic discharge. Be sure to be
connected to ground (e.g. the enclosure of the Sunny Mini Central)
before handling anything within the enclosure of the Sunny Mini
Central.

Installation Guide SMC50_60-11:SE2006 Page 9

Safety Instructions SMA Technologie AG

Page 10 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Overview

3 Overview

3.1 Device Description

The following figure shows the different components and connection areas of an
open Sunny Mini Central 5000/6000 inverter.

Varistors
page 47

Communication socket (RS232,
RS485, NLM Piggy-Back, radio)

Socket for dis­play unit (Sunny
Display)

LEDs indicating
operating state

Communication
terminal

Socket for PLC
(Powerline Com­munication) pow­er unit

Terminals (PE),
page 27

Terminals (AC),
page 27

PV input plug (DC),

page 29

Installation Guide SMC50_60-11:SE2006 Page 11

Cable gland for com-

munication

Cable gland for AC

connection cable

Overview SMA Technologie AG

3.2 External Dimensions

250 mm

430 mm

600 mm

Page 12 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Overview

3.2.1 OptiCool Temperature Management

With the patented dual compartment cooling system
OptiCool, SMA now offers a technical solution combin­ing both passive and active cooling systems. An "intel­ligent temperature management” is the result.

In order to achieve maximum efficiency the whole en­closure of the inverter becomes part of the cooling sys­tem. It does not only contain and protect the
components but also functions as a “cooling air distrib­utor” and heat distributor.

The actual heat sink, as central component of the pas­sive heat dissipation, is positioned within the enclosure
in such a way as to divide it into two compartments. The
highly sensitive electronics separated from the main
heat sources by the heat sink is securely protected from
external influences, such as moisture and dirt, in the
front waterproof compartment.

In the rear part, the temperature-intensive components,
such as chokes and transformers, which are either sep­arately sealed or are intensive to ambient influences,
are installed.

A specifically designed active cooling system is posi­tioned on the bottom of the rear compartment. Depend­ing on the temperature of the power semiconductors
and the inductive components it is automatically activat­ed and adjusts its speed according to the requirements
of a balanced heat dissipation within the device.

The air stream produced by the fans is effectively can­alized through a stream tunnel. It dissipates the waste
heat of the heat sink as well as the components in­stalled in this part.

Using OptiCool reduces the components' temperature in the entire inverter resulting
in high reliability and excellent overload performance. The efficiency of the inverter
and thus of the entire PV plant can therefore be increased.

Using a dual compartment system with a waterproof area for the electronics makes
the inverter suitable for inside as well as outside installation (near the PV generator).

Installation Guide SMC50_60-11:SE2006 Page 13

Overview SMA Technologie AG

Page 14 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Requirements for the Installation

4 Requirements for the Installation

Please make sure to fulfill all conditions below before installing and commissioning
the Sunny Mini Central 5000/6000.

4.1 Requirements: Mounting Place

The Sunny Mini Central 5000/6000 has a relatively high weight of
63 kg. Please keep this in mind when selecting the place where and
how to mount the Sunny Mini Central 5000/6000.

The ambient temperature must be within -25°C and +60 °C.

The Sunny Mini Central 5000/6000 should be installed at a place
where it is not exposed to direct sunlight - otherwise this may reduce
the yield of the PV plant due to the higher temperature.

63 kg

The Sunny Mini Central is designed to be mounted on a vertical wall. For an optimum
energy yield and the most convenient operation, vertical installation at eye-level is
preferable. In case it is absolutely necessary to tilt the Sunny Mini Central to the back
the maximum angle is 45 °. If installing the unit outdoors, make sure that it is not
slanting forwards. We advise against installing the unit in a horizontal position
outdoors.

It is not reccomended to install the Sunny Mini Central lying on the back side with the
lid facing upwards.

Mount the Sunny Mini Central in a vertical

position or with a slight angle to the back.

Installation Guide SMC50_60-11:SE2006 Page 15

Do not mount the Sunny Mini Central with

an angle to the front or on the back.

Requirements for the Installation SMA Technologie AG

Important for the selection of the location:

Unintended removal of the PV plug connectors can damage the
connectors and even result in serious injuries. Install the Sunny
Mini Central 5000/6000 at a place where an unintended removal
of the PV plug connectors (e. g. by children) is not possible.

Individual components in the Sunny Mini Central can reach a tem­perature of more than 60 °C.

Do not install the Sunny Boy on flammable construction materials,
in areas where highly inflammable materials are stored or in po­tentially explosive environments!

Please make sure there is a sufficient space for heat dissipation! In a normal environ­ment the following clearances should be provided for the Sunny Mini Central 5000/
6000:

Minimum clearances

Lateral 30 cm

30
cm

Top 30 cm

Bottom 30 cm

Front 5 cm

30 cm

5

cm

30
cm

30 cm

If you decide to install the Sunny Mini Central 5000/6000 in an area with high am­bient temperatures, you should enlarge the clearances. Otherwise the Sunny Mini
Central 5000/6000 could take air in from the devices next to it. Ensure sufficient ven­tilation.

Page 16 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Requirements for the Installation

In a living area the Sunny Mini Central 5000/6000
should not be mounted on plaster panels etc. in order
to avoid noises.

We recommend to install the inverter on a firm and stur­dy surface.

The Sunny Mini Central 5000/6000 will emit a slight
noise during operation. This noise can be annoying
when the Sunny Mini Central is installed within a living
area.

Installation Guide SMC50_60-11:SE2006 Page 17

Requirements for the Installation SMA Technologie AG

4.2 Requirements: PV-Modules

The Sunny Mini Central 5000/6000 is designed for the connection of large scales
with homogeneous structure (PV modules of the same type, same direction and slant).

The „Sunny Design“ tool will help to dimension and check the size of your strings with
respect to the inverter you intend to use. The „Sunny Design“ tool is available for
download at www.SMA.de.

The device has eight PV plug connectors (two for each string). The connecting cables
of the PV panel therefore have to be equipped with such plug connectors as well. A
connection kit for the connection of loose cable ends in a string can be purchased as
an accessory. In the following you find the SMA order numbers for the different PV
plug connectors:

• Multi-Contact 3 mm: „SWR-MC“

• Multi-Contact 4 mm: „MC-SET“

• Tyco: „TYCO-SET“

Limits for DC input

max. voltage 600 V (DC)

max. input current 26 A (DC)

The strings are connected in parallel inside the Sunny Mini Central 5000/

6000. Check if the cabling of the generator can handle high short-circuit cur­rents. See also chapter 5.3 „Reverse Current” (page 30).

4.3 String sizing of Sunny Mini Central PV plants

Different from the Sunny Mini Centrals you are able to connect three or more strings
in parallel to the Sunny Mini Central 5000/6000. This sounds not very critical, but a
consequence is that failures which are not harmful in string plants have to be consid­ered in plants with big generators: Because of short circuits. See also chapter 5.3
„Reverse Current” (page 30).

4.4 Requirements: Grid 230 V (AC)

The relevant technical regulations as well as specific re­quirements defined by the local public utility have to be
complied with. The terminals of the Sunny Mini Central
5000/6000 are suitable for cables with a cross-section
of up to 16 mm² . Their outer diameter should be between 11 mm and 25 mm. If you
choose a cable with a diameter less than 14 mm (at least 11 mm), you have to
change the rubber grommet of the connection. A smaller rubber grommet is included
in the shipping box.

The Sunny Mini Central 5000/6000 is connected with three wires (L, N, PE).

Page 18 SMC50_60-11:SE2006 Installation Guide

o

11 ... 25 mm

max. 16 mm²

SMA Technologie AG Requirements for the Installation

Each connection to a Sunny Mini Central
5000/6000 must be equipped with a sep­arrate circuit breaker 40 A. No other con­sumers may be connected to the cable.

Sizing of a circuit breaker for the AC line of a photovoltaic invert­er for utility interaction

Several factors have to be considered when you define the size of the circuit
breaker for your PV plant:

• Cable type (material and isolation)

• Ambient temperature surrounding the cable (higher temperatures reduce the con­ducting capacity of the cable)

• Type of installation for the cable (can also reduce the conducting capacity of the
cable)

• Bundling of cables (can reduce the conducting capacity of the cable)

• Loop impedance [Z] (reduces the current that flows in case of a ground fault cur­rent through a body and has influence on the tripping characteristics of the circuit
breaker)

• Adequate clearance between the circuit breakers in order to avoid excessive
heating (automatic circuit breakers trip earlier when they are warmer).

• Fuse selectivity

• Protection class of the connected consumer (VDE 0100 Part 410 "Protection
against electric shock"

a

and/or the international standard IEC 60364-4-41:1992)

The following standards have to be complied with:

• DIN VDE 0298-4 ("Types of cable installation and conducting capacity")

1

• DIN VDE 0100 Part 430

("Protection measures for protection of cables
and conductors in terms of overcurrent") and/or the international stan­dard IEC 364-4-43:1977 and IEC 364-4-473:1977

1

• VDE 0100 Part 410

("Protection against electric shock") and/or the inter-

national standard IEC 60364-4-41:1992

a. The standards mentioned above are to be only used as a guideline for your in-

stallation. The above mentioned standards apply for installations in Germany.
Please note that other standards will apply for different countries throughout the
world.

Installation Guide SMC50_60-11:SE2006 Page 19

Requirements for the Installation SMA Technologie AG

An example for determining the rating of the AC circuit breaker is specified in detail
in chapter 10 „Sizing of a Circuit Breaker” (page 51).

The system impedance at the installation site of the Sunny Mini Central 5000/6000
must be less than 1 Ohms for the islanding detection and the fuses to work properly.
Furthermore you should have a suitable cable cross-section in order to keep the loss­es below 1 % at nominal power. The according losses with respect to cable length
and cross-section are illustrated below:

Losses of the Sunny Mini Central 5000

Do not use cables where losses will exceed 1.0 %

Losses

Length

The maximum cable lengths for the different cable cross-sections are as follows:

Conductor cross-

section

4.0 mm² 6.0 mm² 10.0 mm² 16.0 mm²

Max. length 12 m 18 m 31 m 49 m

Page 20 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Requirements for the Installation

Losses of the Sunny Mini Central 6000

1,4%

1,2%

1,0%

0,8%

0,6%

Losses

0,4%

0,2%

0,0%

0 m

4,0 mm²

5 m

10 m 15 m 20 m 25 m 30 m 35 m 40 m 45 m 50 m

Do not use cables where losses will exceed 1.0 %

6,0 mm²

10,0 mm²

Sunny Mini Central 6000

Length

16,0 mm²

The maximum cable lengths for the different cable cross-sections are as follows:

Conductor cross-

section

4.0 mm² 6.0 mm² 10.0 mm² 16.0 mm²

Max. length 10 m15 m25 m41 m

The Sunny Mini Central 5000/6000 is designed for 230 V grids. The voltage should
be within 198 V and 260 V and the frequency should be within 49.8 Hz and

50.2 Hz. All settings shown below are based on the German standard DIN VDE

0126. You are also able to use other settings.

Limits for AC output

Voltage range 198 V ... 260 V

Frequency range 49.8 Hz ... 50.2 Hz

Voltage range

(without anti-islanding)

Frequency range

(without anti-islanding)

180 V ... 260 V

45.5 Hz ... 54.5 Hz

The Sunny Mini Central 5000/6000 is equipped with an automatic 50 Hz / 60 Hz
utility frequency detection. It can therefore be connected to a 50 Hz or 60 Hz utility
without any further configuration changes. Pay attention to the local utility regula­tions in any case.

Installation Guide SMC50_60-11:SE2006 Page 21

Requirements for the Installation SMA Technologie AG

Grid Impedance

In the following example the output power (Uac) is reduced to 260 V. You are also
able to reduce the output power of the Sunny Mini Central 5000/6000 according to
the national standards.

Because of a high grid impedance the Sunny Mini Central 5000/6000 can receive
a high AC voltage at the connection point. The output voltage (Uac) of the Sunny
Mini Central 5000/6000 is limited to 260 V. If the Sunny Mini Central 5000/6000
exceeds 260 V, it stops feeding to the grid immediately and indicates a „grid fail­ure“.

Which power you can feed into the grid, without stopping operation because of high
AC voltages, is shown in the diagram below.

1,5

1,4

1,3

1,2

1,1

1,0

0,9

0,8

Grid Impedance [Ohm]

0,7

0,6

0,5

0 5 10 15 20 25 30

250 V 240 V 230 V 220 V 210 V 200 V

Power [kW] per Phase

To estimate how many Sunny Mini Central 5000/6000 can operate on one phase
you need the following values:

• Grid voltage without feeding

• Grid impedance at the connection point of the Sunny Mini Central 5000/6000

The diagram shows the respective curve for the AC voltage without feeding. The re­spective curve for power per phase (X axis) results in subject to the grid impedance
(Y axis).

Page 22 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Requirements for the Installation

Example

The grid voltage without feeding averages 230 V.

The grid impedance at the connection point averages 1.2 Ohm.

1,5

1,4

1,3

1,2

1,1

1,0

0,9

0,8

Grid Impedance [Ohm]

0,7

0,6

0,5

0 5 10 15 20 25 30

230 V

Power [kW] per Phase

The indicated power on the x axis complies approx. 6.2 kW per phase.

In consequence you should install only one Sunny Mini Central 5000/6000 per
phase. To install a plant with a higher power that does not stop feeding because of
AC over voltage, you should check the connection conditions of the Sunny Mini Cen­tral 5000/6000 (e. g. by using a cable with a higher cross-section).

Installation Guide SMC50_60-11:SE2006 Page 23

Requirements for the Installation SMA Technologie AG

Page 24 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Installation

5 Installation

5.1 Mounting

For trouble-free mounting of the Sunny Mini Central
5000/6000 we recommend to use the bracket for wall
installation included in delivery. You can mount it verti­cally in firm concrete or stone walls with e. g. stainless
steel 8 mm x 50 mm hexagon screws according to DIN
571, an appertaining washer and with a 10 mm dowel.

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Keep the weight of the Sunny Mini Central 5000/6000
(63 kg) in mind.

For installing your Sunny Mini Central 5000/6000 on
wooden wall studs, use the four holes in the middle of
the wall-mounting bracket. Position the wall-mounting
bracket against a stake of the wall. Make sure that the
wall you choose to mount the Sunny Mini Central
5000/6000 on is sturdy enough to support its weight

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(63 kg) over a long period of time and that the wall is
vertical.

1. Mount the bracket. To mark the positions for drill
holes you can also use the bracket as a drilling
template.

2. Hang the upper fixing straps of the Sunny Mini
Central 5000/6000 into the bracket (2) so that it
cannot be shifted sideways any more.

3. Secure the Sunny Mini Central 5000/6000
against lifting off by screwing the M6x10 screw
(included in delivery) into the lower middle fixing
strap (3).

4. Ensure the Sunny Mini Central 5000/6000 has
been tightly fastened.

2

1

1

3

Installation Guide SMC50_60-11:SE2006 Page 25

Installation SMA Technologie AG

5.2 Electrical Installation

Check the correct polarity before you connect the PV strings!

The following figure shows the complete cabling of a Sunny Mini Central 5000/
6000:

++++

String 1

String 2

String 3
String 4

230 Vac:

---

-

NL1

Communication

max. 16 mm

32A

B

2

Page 26 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Installation

Connection of AC output

Please follow the steps below:

1. Check the grid voltage. If it is above 260 V
(German standard), the Sunny Mini Central
5000/6000 stops operation. The local public
utility company should solve this problem.

The maximum grid voltage for feeding

max. 260 V!

operation is 260 V!

2. Disconnect the grid (switch off the circuit break­er), secure it against accidental reactivation and
ensure that it is disconnected.

Off!

1. 2. 3.

Before opening the Sunny Mini Central

5000/6000 check whether the AC

output is safely isolated from supply!

3. Unscrew the lid from the enclosure of the Sunny
Mini Central 5000/6000 and remove the lid.

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Photovoltaic inverter

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4. Connect the AC cable as illustrated in the figure

L

on the side. Use the cable gland that is included
in the delivery of your Sunny Mini Central
5000/6000. Phase (L) and Neutral (N) may not
be mixed up.

NL1

230 Vac:

N

Connection of „L“ and „N“

Installation Guide SMC50_60-11:SE2006 Page 27

Installation SMA Technologie AG

5. Connect the PE conductor of the grid cable.

Connection of PE conductor

6. Fasten the lid to the enclosure of the Sunny Mini Central 5000/6000 by tighten­ing the six screws. Don’t forget the lock washers. The notches of the lock washers
should face to the lid.

Do not switch on the circuit breaker yet! The Sunny Mini Central
5000/6000 may only be connected to the AC grid when the PV
strings have been connected and the device is tightly closed.

Page 28 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Installation

PV String (DC) Connection

Connect the PV strings as follows:

1. Check the PV generator connections on their
correct polarity and compliance with the maxi­mum string voltage of 600 V DC, see chapter

4.2 „Requirements: PV-Modules” (page 18).

The voltage from the strings is very dangerous! Be very careful
and pay attention to all applicable safety regulations!

2. Measure the DC voltages between each PV plug
connector of a string and ground potential. Fol­low the safety instructions!

3. If the measured voltages are constant and their
total approximately corresponds to the open-cir­cuit voltage of the string, a ground fault has oc­cured in this string. The ratios of voltages
approximately indicate where the ground fault
can be found.

PE

When you have found a ground fault in a string, only connect it to
the Sunny Mini Central 5000/6000 after you have removed the
cause for the ground fault in the PV generator.

4. Repeat steps 2 and 3 for each string.

5. Connect the trouble-free PV strings to the Sunny
Mini Central 5000/6000. Make sure to connect
them with correct polarization.

++

-

-

6. Close off the unneeded DC input sockets using
the protective caps supplied in the accessories
kit.

Installation Guide SMC50_60-11:SE2006 Page 29

String A

String B

Installation SMA Technologie AG

5.3 Reverse Current

Information about the design of generators for PV plants with
Sunny Mini Central

In contrast to the „Sunny Mini Central“ string inverters, mostly three and more strings
are connected in parallel within a PV generator of a „Sunny Mini Central 5000/
6000“ (SMC). In case of such large generators failures may occur that are uncritical
in string plants: module currents misrouted by short circuits can load a PV module with
a so called reverse current that may exceed the normal maximum current (short cir­cuit current) of the PV module.

When can a reverse current occur?

In principal, a reverse current can only occur when modules are connected in parallel
and the open terminal voltage (open-circuit voltage Uoc) of the individual parallel
strings is different. In normal operation mode, this is mostly avoided due to the fact
that the strings are identical. Even in the special case of shadowing no considerable
reverse current occurs as shadowing has no significant impact on Uoc.

In normal operation no excessive reverse current can occur in a PV plant that has
been accurately designed!

Thus, a reverse current can only arise in case the open terminal voltage of a module
string is significantly below the open circuit voltage of the other strings connected in
parallel due to a failure in the PV generator (e.g. short circuit of one or several mod­ules). At worst, the voltage applied to the defective string is in the range of the re­maining generator's MPP voltage (UMPP). Due to the internal diode structure of the
PV cell a reverse current flows through the defective generator string. This reverse
current may cause an extreme heat all the way to the destruction of the string's mod­ules depending on the current intensity!

The failures indicated below may result in reduction of the open terminal voltage of
a generator string and thus in a reverse current in case of connection in parallel:

• Short circuit of one or several modules,

• Short circuit of one or several cells in the module,

• Double ground fault of a module and/or the wiring.

Even if these failures are very unlikely and rare in the field precautions must be taken.
This failure involves a high potential for damages and dangers. All modules of the
affected Strings can be damaged and cause secondary damages due to the high

Page 30 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Installation

thermal impact. It is therefore not amazing that UL certifiers in the USA already con­sider this aspect and that the reverse current resistance is a value specified by default
in US datasheets of PV modules.

Current of the defective string =
Sum of the current of the other strings

+

-

L

N

Installation Guide SMC50_60-11:SE2006 Page 31

Installation SMA Technologie AG

How can one avoid reverse currents within the modules?

Bypass diodes that are currently state of the art in module design have no impact on
the reverse current within the module but only reduce the effects of possible shadow­ing.

You have the following possibilities to cope with the reverse current problems:

1. String Technology

All components of a string (modules, cables, plug connectors) must be designed for
the remaining generator short-circuit current as reverse current. This always applies
in case of parallel connection of a maximum of two strings as the resulting reverse
current of a (damaged) string can achieve at most the value of the short circuit current
of the (faultless) string.

2. String Diodes

Due to so called string diodes connected in serial circuit with the individual strings
only the reverse current within the respective string is avoided. Disadvantage: the di­ode is permanently in serial circuit with the respective generator string and the re­spective string current flows through it. Respectively high permanent losses result. In
addition, failure of the diode may cause a loss of the protective function or failure of
the entire string.

3. String Fuses

String fuses connected in serial circuit with the individual strings allow to limit the re­verse current in the respective string to the permitted maximum. The losses at the
string fuses are lower than the losses you would observe with string diodes. A string
fuse failure can be identified by a fuse control or an "intelligent" failure control of the
PV panel.

The first option is to be considered for the design of a cost-efficient plant. The Sunny
Mini Central 5000/6000 is therefore delivered with MC and Tyco plug connectors
that have a rating of 30 A current.

Design Tips

The following is specifically to be checked and/or ensured:

1. Do all strings have the same number of modules connected in serial circuit?

2. What is the maximum reverse current in a defective string under nominal condi­tions?
Example: Generator consisting of 4 strings of modules with short circuit current
of 5 A maximum reverse current is 3 x 5 A = 15 A.

3. Are the modules suitable for such a reverse current?

4. Are the plug connections of the modules and the inverter suitable for such a re­verse current?

5. Is the string cabling suitable for such a reverse current?

Page 32 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Installation

5.4 Activation

You can activate the Sunny Mini Central 5000/6000 when:

• The lid has been tightly screwed on.

• The AC (grid) cable has been correctly connected.

• All the DC (PV) strings have been connected and all unused DC plug connectors

on the underside of the inverter have been closed with the protecting caps.

Proceedings for Activation

1. Switch the circuit breaker on.

2. Check whether the LEDs indicate trouble-free
operation of the Sunny Mini Central 5000/
6000 based on the following table. If this is the
case commissioning has been successfully com­pleted.

If the lower yellow LED repeatedly blinks once a second for four
times, immediately disconnect the grid voltage and the PV gener­ator from the Sunny Mini Central 5000/6000. The input voltage is
too high. The inverter might be damaged!

On!

Off

Check whether string voltages comply with limiting values stated in chapter 4.2 „Re­quirements: PV-Modules” (page 18). If the values are too high, the planner / installer
of the PV generator must modify the strings.

If the LED blinks again when the PV plant is reconnected to the inverter although
string voltages have been checked to be ok, disconnect the PV panel again and con­tact SMA Technologie AG (see chapter 11 „Contact” (page 55)).

Installation Guide SMC50_60-11:SE2006 Page 33

Installation SMA Technologie AG

Green Red Yellow Status

off off OK (feeding)

permanently on

blinking fast

(3 x per second)

blinking slowly

(1 x per second)

shortly turns off

(approx. 1 x per

second)

off

permanently on

off off OK (Stop)

permanently on off failure

off off

permanently on permanently on failure

off off OK (derating)

permanently on off failure

off

permanently on

off failure

permanently on OK (Initialization)

OK (waiting, grid moni-

toring)

off OK (stand-by)

off / blinking failure

off failure

off / blinking failure

You will find a detailed description of failure messages and their causes in the „Op­erating Instructions“.

Page 34 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Opening and Closing the Sunny Mini Central

6 Opening and Closing the Sunny Mini Central

If the inverter has to be openend always follow the safety instruc­tions given in chapter 2 „Safety Instructions” (page 9).

6.1 Opening the Sunny Mini Central

Caution: Stick to the order specified below!

1. Switch off the AC connection.

2. Prevent accidental reconnection!

3. Disconnect the PV generator from the Sunny Mini Central 5000/6000 by pulling
off all the connectors.

4. Wait 30 minutes! (This is necessary to let the internal capacitors dis­charge.)

5. Remove the six screws on the lid and pull the lid slightly forward.

6.2 Closing the Sunny Mini Central

Caution: Stick to the order specified below!

1. Attach the lid to the enclosure of the Sunny Mini Central 5000/6000 by tighten­ing the six screws. Don’t forget the lock washers. The notches of the lock washers
should face to the lid.

2. Connect the PV generator.

3. Switch on the AC circuit breaker. This activates the Sunny Mini Central 5000/

6000.

4. Check whether the LEDs of the Sunny Mini Central 5000/6000 indicate trouble­free operation.

Installation Guide SMC50_60-11:SE2006 Page 35

Opening and Closing the Sunny Mini Central SMA Technologie AG

Page 36 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Technical Documentation

7 Technical Documentation

7.1 Sunny Mini Central 5000

7.1.1 Data PV Generator Connection

Max. input open-circuit voltage U

Input voltage, MPP operation U

Max. input current I

Max. input power P

Recommended generator
power

All-pole disconnector on DC input side DC plug connector

Surge voltage protection thermally monitored varistors

Voltage ripple U

Personnel protection Ground Fault monitoring

Internal consumption in operation < 7 W (stand-by)

Pole confusion prevention by short-circuit diode

7.1.2 Data Grid Connection

Nominal output power P

Permanent output power at 45 °C 5500 W

Peak output power P

Nominal output current I

Harmonic distortion of output
(with KUnom < 2 %, PAC > 0,5 PACnom)

Short-circuit resistance Imax = 30 A

Operating range, grid voltage U

Operating range, grid frequency f

All-pole disconnector on grid side independent disconnection device (MSD),

Phase difference (related to basic wave of
current)

Overvoltage category III

Test voltage 2 kV (1 s unit / 60 s type test)

Surge voltage test 4 kV (1.2/50 µs)

Internal consumption in stand-by 0.25 W

0 600 V (at -10 °C module temperature)

PV

PV

PV max

PV

PP

ACnom

ACmax

ACnom

T

HDIAC

AC

AC

cos Phi 1

250 V ... 600 V DC
(250 V DC at 230 V AC)

26 A

5750 W

6350 Wp

< 10 % of input voltage

(Riso > 2 MΩ)

5000 W

5500 W

21.7 A

4 %

198 ... 260 V AC
(adjustable 180 ... 265 V)

49.8 ... 50.2 Hz
(adjustable 45.5 ... 54.5 Hz)

(2 independant systems)

(serial interface: 6 kV)

Installation Guide SMC50_60-11:SE2006 Page 37

Technical Documentation SMA Technologie AG

7.2 Sunny Mini Central 6000

7.2.1 Data PV Generator Connection

Max. input open-circuit voltage U

Input voltage, MPP operation U

Max. input current I

Max. input power P

Recommended generator
power

All-pole disconnector on DC input side DC plug connector

Surge voltage protection thermally monitored varistors

Voltage ripple U

Personnel protection Ground Fault monitoring

Internal consumption in operation < 7 W (stand-by)

Pole confusion prevention by short-circuit diode

0 600 V (at -10 °C module temperature)

PV

PV

PV max

PV

250 V ... 600 V DC
(250 V DC at 230 V AC)

26 A

6300 W

7000 Wp

PP

< 10 % of input voltage

(Riso > 2 MΩ)

7.2.2 Data Grid Connection

Nominal output power P

ACnom

Permanent output power at 45 °C 6000 W

Peak output power P

Nominal output current I

Harmonic distortion of output
(with KUnom < 2 %, PAC > 0,5 PACnom)

ACmax

ACnom

T

HDIAC

Short-circuit resistance Imax = 30 A

Operating range, grid voltage U

Operating range, grid frequency f

AC

AC

All-pole disconnector on grid side independent disconnection device (MSD),

Phase difference (related to basic wave of

cos Phi 1

current)

Overvoltage category III

Test voltage 2 kV (1 s unit / 60 s type test)

Surge voltage test 4 kV (1.2/50 µs)

Internal consumption in stand-by 0.25 W

5500 W

6000 W

24 A

4 %

198 ... 260 V AC
(adjustable 180 ... 265 V)

49.8 ... 50.2 Hz
(adjustable 45.5 ... 54.5 Hz)

(2 independant systems)

(serial interface: 6 kV)

Page 38 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Technical Documentation

7.3 Description of Devices

You will find a detailed device description in the Operating Instructions.

General Data

Protection Degree according to
DIN EN 60529 IP54

Dimensions (width x height x depth) approx. 430 mm x 600 mm x 250 mm
Weight approx. 63 kg

External interfaces

Data transmission via powerline optional
Data transmission via separate data cable optional,
RS232 / RS485, electrically separated
Data transmission via radio optional

Efficiency

Max. Efficiency ηmax 96 %
European weighted efficiency ηeuro > 95.1 %

The efficiency of the Sunny Mini Central depends on the input voltage coming from
the PV modules. The lower the input voltage, the higher the efficiency.

96

95

94

93

92

Overall efficiency [%]

91

90

0 2000 3000 4000 5000 6000

Installation Guide SMC50_60-11:SE2006 Page 39

250 V

300 V

400 V

500 V

Sunny Mini Central 5000 / 6000

1000

Output power [W]

Technical Documentation SMA Technologie AG

7.4 Sunny Mini Central Operating Parameters

Any unauthorized modifications of the operating parameters can

• Result in serious injuries or casualties due to altered internal
safety precautions within the Sunny Mini Central

• Void the operating permission of the Sunny Mini Central

• Void the warranty of the Sunny Mini Central

Never change the operating parameters without explicit permis­sion and instructions!

The parameters with a grey background are only visible when in installer mode.

Name Unit Range Default

Betriebsart/
Operating Mode

Default GER/ENS

dFac-MAX Hz/s 0.005 ... 4.0 0.25

dZac-MAX mOhm 0 ... 20000 350

E_Total kWh 0 ... 200000

Fac-Delta- Hz 0 ... 4.5 0.19

Fac-Delta+ Hz 0 ... 4.5 0.19

Fan test 0 1 0

h_Total h 0 ... 200000

Inst.-Code

NiTest/
testcurrent Zac

Riso kOhm 0 ... 10000 1000

Speicherfunktion/
Memory Function

Speicher /
Storage

T-Max-Fan °C 0 ... 100 90

T-Start s 5 ... 1600 10 / 300

T-Start-Fan °C 0 ... 100 70

T-Stop s 1 ... 1800 2

T-Stop-Fan °C 0 ... 100 50

Uac-Max / Vac-Max V 180 ... 300 260

Uac-Min / Vac-Min V 180 ... 300 198

Usoll-Konst/
Vconst-Setval

mA 0 ... 25000 16000

V 250 ... 600 600

MPP, UKonst, Stop,
Turbine, MPP

permanent / volatile permanent

MPP

none

Page 40 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Technical Documentation

The following parameters appear in parameter list but cannot be modified:

Name Unit Range Description

Plimit W 5000 /

6000
SMA-SN Serial Number of the Sunny Mini Central
Software-BFR Firmware version of the operation control unit

Software-SRR Firmware version of the current control unit

Upper limit of AC output power

(BFR)

(SRR)

Installation Guide SMC50_60-11:SE2006 Page 41

Technical Documentation SMA Technologie AG

Page 42 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Checking the heat dissipation

8 Checking the heat dissipation

You only need to check the heat dissipation, in case you recognize that the fans are
severely clogged or the Sunny Mini Central is often in the operation mode Derating.
Whether the Sunny Mini Central works in the operation mode Derating or not, de­pends on the ambient temperature and the efficiency of the ventilation. I. e. a device
with clogged filters (insufficient ventilation) and a low ambient temperature, may sel­dom or even not change to the mode Derating. But a device with sufficient ventilation
and a high ambient temperature may relatively often change to the mode Derating.

8.1 Cleaning the fans

If the filters are only clogged with loose dust you can clean them with a vacuum clean­er. If the fans are still clogged, you have also the possibility to remove the fans for
cleaning them.

The fans are mounted on a plate on the bottom side of the Sunny Mini Central. To
clean the fans please follow the steps below:

1. Remove the six screws on the bottom side of the
Sunny Mini Central.

Pac 903W
Upv 330V

2. Carefully remove the plate with the fans and dis­connect the cable leading to the inside of the in­verter.

3. Unlock the connectors of the fans and remove
them carefully.

4. The fans are mounted to the plate with four nuts
each. Undo the four nuts and remove the fans, the
spacers and filters located behind each fan.

5. To clean the fans, spacers and filters use a soft
brush or cloth. Do not use air pressure for cleaning the fans. This will damage
the fans.

Installation Guide SMC50_60-11:SE2006 Page 43

Checking the heat dissipation SMA Technologie AG

6. When the fans are clean, reinstall them using the above steps in reverse order.
Pay attention to the direction of the fans. Do not forget to reconnect the plugs of
the fans. After reinstalling the fans, check their function (see following chapter).

Page 44 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Checking the heat dissipation

8.2 Testing the fans

You can verify the operation of the fans in two ways:

• Set the parameter „Fan Test“ to „1“ (with Sunny Data, Sunny Data Control or

with the data logger Sunny Mini Central Control).

• Use the jumper on the control board of the Sunny Mini Central (see figure below).

For setting the jumper for the fan test, proceed as follows. Stick to the order specified
below!

1. Open the Sunny Mini Central 5000/6000 as described in chapter 6.1 „Open­ing the Sunny Mini Central” (page 35).

2. Put the jumper in the slot shown in the picture below. The jumper is included in
delivery

3. Close the Sunny Mini Central as described in chapter 6.2 „Closing the Sunny
Mini Central” (page 35) and switch it on again.

4. The Sunny Mini Central can not detect the jumper, until you deactivate and re­activate it.

Position of the jumper

After setting the jumper, switch on the Sunny Mini Central. Check the air flow of the
fans. The Sunny Mini Central aspirates the air from the bottom side and blows it out
on the sides of the device. Pay attention to strange sounds, they might be a hint for
an incorrect installation or a defective fan.

When you finished testing the fans you have to reset the parameter „Fan-Test“ to „0“,
or you have to remove the jumper.

Installation Guide SMC50_60-11:SE2006 Page 45

Checking the heat dissipation SMA Technologie AG

8.3 Cleaning the Fins

The fins are mounted on both sides of the Sunny Mini Central. To clean the fins follow
the steps below.

1. Turn off the Sunny Mini Central by following the steps 1 to 4 of chapter 6.1
„Opening the Sunny Mini Central” (page 35)

2. Remove the six screws on both sides of the Sunny Mini
Central.

3. Take out the fins. Behind the fins are the filters. Clean
the filters and fins with a soft brush, cloth or air pres­sure.

4. When the fins and filters are clean, reinstall them us­ing the above steps in reverse order. Don’t forget the
lock washers. The notches of the lock washers should
face to the enclosure.

Page 46 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Exchanging Varistors

O

9 Exchanging Varistors

The Sunny Mini Central 5000/6000 is a very complex technical device. Therefore
there are only a few possibilities to repair failures on site. Please do not try to make
repairs otherwise than described in this document. Make use of our exchange service
and the repair service of SMA Technologie AG.

If the red status LED is permanently on during operation please first make sure that
there is no ground fault in the PV generator.

1. Disconnect the grid (switch off the circuit break­er), secure it against accidental reactivation and
ensure that it is disconnected.

ff!

1. 2. 3.

Ensure that the AC voltage is off before

you open the Sunny Mini Central 5000/

2. Disconnect the PV plug connectors of all strings.

String A

String B

Disconnect the PV strings!

3. Measure voltages between one PV plug connec­tor of each string and the ground potential. Fol­low all applicable safety instructions!

PE

++

6000!

-

-

Measure voltages between PV plug

connectors and the ground potential.

The voltage from the strings is very dangerous! Be very careful
and pay attention to all applicable safety regulations!

4. If the voltages measured are constant and their total is approximately equal to
the open-circuit voltage of the string, there is a ground fault in this string. Its ap­proximate position can be deducted from the ratios of voltages.

Installation Guide SMC50_60-11:SE2006 Page 47

Exchanging Varistors SMA Technologie AG

5. Repeat points 3 and 4 for each string.
If you have found a ground fault it is probably unnecessary to exchange the
varistors. Make sure to remove the ground fault instead. This should normally
be done by the installer of the PV plant. In this case proceed with point 10, but
without reconnecting the faulty string! Protect its PV plug connectors against
touching (e. g. by protective caps or insulation strip with sufficient electric
strength).

If you have not found any ground fault in the PV generators, probably one of
the thermally monitored varistors has lost its protective function. The varistors
are subject to wear and tear and their function is reduced in the course of their
aging or in case of repeated strain placed on them by surge voltages. You can
now check the varistors as described below while following the safety instruc­tions given in chapter 2 „Safety Instructions” (page 9).

6. Unscrew the lid of the Sunny Mini Central 5000/6000 and remove it. Test safe
isolation from supply.

7. Test all varistors for an electric connection between terminals 2 and 3. If there
is no electric connection the varistor is useless. The position of varistors in the
Sunny Mini Central 5000/6000 can be seen in chapter 3.1 „Device Descrip­tion” (page 11).

8. Replace the defective varistor by a new one as
shown in the figure on the left. Ensure correct
orientation of the varistor! Please contact SMA
if you have not received special tools to move

Unlock the varistor

with the

extractor tool

the terminals (included in delivery of replace­ment varistors). However, the terminal contacts
can also provisionally be released one by one
with a suitable screwdriver. The failure of a
varistor is normally due to circumstances that
apply to all varistors in a similar manner (tem-

Remove varistor

perature, age, induced surge voltages). We
therefore strongly recommend not only to ex­change the defective one, but all two. These
varistors are specially manufactured for use in

3

2

1

the Sunny Mini Central 5000/6000 and are not
commercially available. They have to be pur­chased from SMA Technologie AG direct (SMA
order name:“SB-TV4“).

The wire with the little
dent must be inserted

into the terminal

number 1 when you

install the new varistor

Page 48 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Exchanging Varistors

In case there are no spare varistors available the Sunny Mini Cen­tral 5000/6000 still can feed electricity into the grid. The input is
not protected against overvoltages in this case. Replacement varis­tors should be obtained as soon as possible. In systems with a high
risk of overvoltages, the Sunny Mini Central 5000/6000 should not
be operated with defective varistors.

9. Attach the lid to the enclosure of the Sunny Mini Central 5000/6000 by tighten­ing the six screws. Don’t forget the lock washers. The notches of the lock washers
should face to the lid.

10. Connect the faultless strings of the PV panel. En­sure correct allocation to strings.

-

11. Close off the unneeded DC input sockets using

++

-

the protective caps supplied in the accessories
kit.

String A

String B

12. Switch on the circuit breaker.

On!

13. Check whether the LEDs of the Sunny Mini Cen­tral 5000/6000 show trouble-free operation.

Off

If you have found neither a ground fault nor a defective varistor there probably is a
fault in the Sunny Mini Central 5000/6000. Please contact the SMA hotline in this
case to discuss further proceedings.

Installation Guide SMC50_60-11:SE2006 Page 49

Exchanging Varistors SMA Technologie AG

Page 50 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Sizing of a Circuit Breaker

10 Sizing of a Circuit Breaker

Example for the sizing of a circuit breaker for the AC line of a photovoltaic in­verter for utility interaction in terms of temperature.

Photovoltaic plant with 9 inverters type Sunny Mini Central SMC 6000 with 3
inverters per phase

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Required data of the used inverters:

• max. output current: 26 A

• max. permissible rating of the circuit breaker for one inverter: 40 A

The type of cable as well as the type of cable installation and several other conditions
have influence on the maximum rating of the circuit breaker for the inverter.

In this example we assume that the cable used (6 mm²) can be used for nominal cur­rents up to 32.2 A in this example.

Selection of the circuit breakers:

• The maximum possible nominal current of the cable used and the maximum pos­sible rating for the inverter now define the maximum possible nominal current of
the circuit breakers.

• 32 A are possible in our example for one inverter.

However, the thermal suitability of the line circuit breaker still needs to be checked.

Installation Guide SMC50_60-11:SE2006 Page 51

Sizing of a Circuit Breaker SMA Technologie AG

Several aspects that have affect on the load must be considered when you select a
circuit breaker. These aspects are specified in the data sheets of the circuit breakers.

Example for the sizing of a 32 A circuit breaker with B characteristics for the
AC line of a photovoltaic inverter for utility interaction while the circuit breakers
are installed right next to each other without gap (with respect to the thermal
conditions).

One vendor of circuit breakers for example specifies the ratings for an ambient tem­perature of 50 °C.

Aspects that have an affect on the load specified in the data sheets:

• Reduction of the tolerable current because of continuous load > 1 h = 0.9

• Reduction of the tolerable current due to installation of 9 circuit breakers right
next to each other without gap = 0.77

• Increase of the tolerable current resulting from ambient temperatures of 40 °C in
the distribution box = 1.07

c

b

a

a. In photovoltaic applications continuous loads of over 1 h are possible.
b. The coefficient is 1 in case there is only one single circuit breaker.
c. Resulting from the sizing of the circuit breakers for ambient temperatures of

50 °C.

Page 52 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Sizing of a Circuit Breaker

Result:

The nominal current of the circuit breaker is

Inr = 32 A x 0.9 x 0.77 x 1.07 = 23.7 A

The circuit breaker selected for this installation is not suitable due to the fact that the
maximum tolerable current of the circuit breaker is below the maximum current of the
used inverter. It will trip in normal operation.

A solution for this plant would be the installation of the circuit breakers with an 8 mm
gap between each unit. This would result in a reduction coefficient of 0.98 instead of

0.77. This would result in a maximum current of 30 A.

A further solution could be the installation of circuit breakers with a rating of 40 A.
In this case all different aspects have to be evaluated again with respect to this
change. An installation of the circuit breakers in the distribution box without gap be­tween the units would result in a nominal current of Inr = 40 A x 0.9 x 0.77 x 1.07
= 29.6 A.

SMA recommends the installation described above with a gap between the circuit
breakers.

As well as the thermal rating of the circuit breakers and all other factors as specified
in section „Sizing of a circuit breaker for the AC line of a photovoltaic inverter for
utility interaction” (page 19), of course the applicable DIN VDE standards
need to be taken into account. The main ones that apply here are:

• DIN VDE 0100 Part 410 and/or the international standard IEC 60364-4-41:1992

• DIN VDE 0100 Part 430 and/or the international standard IEC 364-4-43:1977
and IEC 364-4-473:1977

• DIN VDE 0298 Part 4

a

also

a. The standards listed here are standards that apply in Germany. Please note that

other standards apply in other countries. Beside the standards above other stan­dards may be applicable in special installations.

Installation Guide SMC50_60-11:SE2006 Page 53

Sizing of a Circuit Breaker SMA Technologie AG

Page 54 SMC50_60-11:SE2006 Installation Guide

SMA Technologie AG Contact

11 Contact

If you have any questions or technical problems with the Sunny Mini Central 5000/
6000 our hotline will be glad to help you. Please keep the following data ready when
calling SMA:

• Type of inverter used

• Number and type of connected modules

• Communication

• Serial number of Sunny Mini Central 5000/6000

Address: SMA Technologie AG
Hannoversche Strasse 1 - 5
34266 Niestetal
Germany

Tel.:[phone] - 499
Fax:[phone] - 4699
[e-mail]
www.SMA.de

Installation Guide SMC50_60-11:SE2006 Page 55

Contact SMA Technologie AG

Page 56 SMC50_60-11:SE2006 Installation Guide

SMATechnologie AG

www.SMA.de

Hannoversche Straße 1–5
34266 Niestetal
Germany
Tel. [phone] - 0
Fax [phone] - 100
www.SMA.de

SMA Technologie AG

SMA America, Inc.
12438 Loma Rica Drive, Unit C
Grass Valley, CA 95945
USA
Tel. [phone]
Fax [phone]
www.SMA-AMERICA.com

SMA Solartechnology China
Room 20F, InternationalMetro Center,
Building A , City Square No. Jia 3,
Shilipu Road, Changyang District
100025 Beijing, PR. China
Tel. [phone]
Fax [phone]
www.SMA-CHINA.com

Page 58 SMC50_60-11:SE2006 Installation Guide