SMA SUNNY CENTRAL 250U User manual

DisconACDC_SCUS-IUS103110 | 98-4009010 | Version 1.0
US
Accessories for Sunny Central
Disconnect Unit for
Sunny Central 250U /500U / 500HE-US/CA and
Sunny Central CP
Installation Guide

SMA America, LLC
2 DisconACDC_SCUS-IUS103110 Installation Guide

SMA America, LLC 
Installation Guide DisconACDC_SCUS-IUS103110 3
Copyright © 2010 SMA America,LLC. All rights reserved.
No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form
or by any means, electronic, mechanical, photographic, magnetic or otherwise, without the prior
written permission of SMA America,LLC.
Neither SMA America,LLC nor SMA Solar Technology Canada Inc. makes no representations,
express or implied, with respect to this documentation or any of the equipment and/or software it may
describe, including (with no limitation) any implied warranties of utility, merchantability, or fitness for
any particular purpose. All such warranties are expressly disclaimed. Neither SMA America,LLC nor
its distributors or dealers nor SMA Solar Technology Canada Inc. nor its distributors or dealers shall
be liable for any indirect, incidental, or consequential damages under any circumstances.
(The exclusion of implied warranties may not apply in all cases under some statutes, and thus the
above exclusion may not apply.)
Specifications are subject to change without notice. Every attempt has been made to make this
document complete, accurate and up-to-date. Readers are cautioned, however, that
SMAAmerica,LLC and SMA Solar Technology Canada Inc. reserve the right to make changes
without notice and shall not be responsible for any damages, including indirect, incidental or
consequential damages, caused by reliance on the material presented, including, but not limited to,
omissions, typographical errors, arithmetical errors or listing errors in the content material.
All trademarks are recognized even if these are not marked separately. Missing designations do not
mean that a product or brand is not a registered trademark.
The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and
any use of such marks by SMA America,LLC and SMA Solar Technology Canada Inc. is under
license.
SMA America, LLC
3801 N. Havana Street
Denver, CO 80239 U.S.A.

SMA America, LLC
4 DisconACDC_SCUS-IUS103110 Installation Guide
IMPORTANT SAFETY INSTRUCTIONS
SAVE THESE INSTRUCTIONS
This manual contains important instructions for the Disconnect Unit for Sunny Central 250U /500U
/ 500HE-US/CA and Sunny Central CP accessory, that must be followed during installation and
maintenance of the accessory.
The Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA and Sunny Central CP are
designed and tested according to international safety requirements, but as with all electrical and
electronic equipment, certain precautions must be observed when installing and/or operating the
Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA and Sunny Central CP. To reduce
the risk of personal injury and to ensure the safe installation and operation of the Disconnect Unit for
Sunny Central 250U /500U / 500HE‑US and Sunny Central CP, you must carefully read and follow
all instructions, cautions and warnings in this installation guide.
Warnings in this document
A warning describes a hazard to equipment or personnel. It calls attention to a procedure or practice,
which, if not correctly performed or adhered to, could result in damage to or destruction of part or all
of the SMA equipment and/or other equipment connected to the SMA equipment or personal injury.
%"/(&3
DANGER indicates a hazardous situation which, if not avoided, will result in death or serious injury.
8"3/*/(
WARNING indicates a hazardous situation which, if not avoided, could result in death or serious
injury.
$"65*0/
CAUTION indicates a hazardous situation which, if not avoided, could result in minor or moderate
injury.
/05*$&
NOTICE is used to address practices not related to personal injury.

SMA America, LLC 
Installation Guide DisconACDC_SCUS-IUS103110 5
Other symbols in this document
In addition to the safety and hazard symbols described on the previous pages, the following symbol
is also used in this installation guide:
Markings on this product
The following symbols are used as product markings with the following meanings.
Information
This symbol accompanies notes that call attention to supplementary information that you must
know and use to ensure optimal operation of the system.
Warning regarding dangerous voltage
The product works with high voltages. All work on the product must only be
performed as described in it‘s documentation.
Electric arc hazards
The product has large electrical potential differences between its conductors. Arc
flashes can occur through air when high-voltage current flows. Do not work on the
product during operation.
Beware of hot surface
The product can become hot during operation. Do not touch the product during
operation.
Observe the operating instructions
Read the documentation of the product before performing any work. Follow all safety
precautions and instructions as described in the documentation.
UL1741 is the standard applied by Underwriters Laboratories to the AC/DC-
Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA to certify that it
meets the requirements of the National Electrical Code®, the Canadian Electrical
Code® CSA C22.1 and IEEE‑929‑2000. IEEE 929-2000 provides recommendations
regarding the proper equipment and functionality necessary to ensure compatible
operation when power generation is connected to the utility grid.

SMA America, LLC
6 DisconACDC_SCUS-IUS103110 Installation Guide
General warnings
8"3/*/(
All electrical installations must be done in accordance with the local codes and National Electrical
Code® ANSI/NFPA 70 or the Canadian Electrical Code® CSAC22.1.
Before installing or using the Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA
and Sunny Central CP, read all of the instructions, cautions, and warnings on the AC/DC-Disconnect
Unit for Sunny Central 250U /500U / 500HE-US/CA and Sunny Central CP in this installation
guide.
Before connecting the Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA and
Sunny Central CP to the power distribution grid, contact the local power distribution grid company.
This connection must be made only by qualified personnel.
Wiring of the Disconnect Unit for Sunny Central 250U /500U / 500HE-US/CA and Sunny Central
CP must be made by qualified personnel only.

SMA America, LLC Table of Contents
Installation Guide DisconACDC_SCUS-IUS103110 7
Table of Contents
1 Notes on this manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.1 Target group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.2 Validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3 Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4 Differences between variants of the Disconnect Unit . . . . . . . . 11
2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1 Appropriate usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3 The Disconnect Unit for Sunny Central . . . . . . . . . . . . . . . 15
3.1 Operating principles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Identifying the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . . . 15
4 Scope of delivery and storage . . . . . . . . . . . . . . . . . . . . . 16
4.1 Unpacking and inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5 Installation of the Disconnect Unit . . . . . . . . . . . . . . . . . . 18
5.1 Choosing the installation site . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.1 Ambient conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.2 Characteristics of the base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.3 Position of the mounting holes and bottom entry sleeves . . . . . . . . . . . . . . . 19
5.1.4 Minimum clearances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1.5 Dimensions and weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.2 Installing the Disconnect Unit onto the base . . . . . . . . . . . . . . . 24
5.3 Opening the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.4 Preparation of the cable entries . . . . . . . . . . . . . . . . . . . . . . . . 27
5.5 Inserting cables into the Disconnect Unit. . . . . . . . . . . . . . . . . . 29

Table of Contents SMA America, LLC
8 DisconACDC_SCUS-IUS103110 Installation Guide
6 Electrical connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1 Overview electrical connections . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1.1 Disconnect Unit for Sunny Central 250U/500U . . . . . . . . . . . . . . . . . . . . . 30
6.1.2 Disconnect Unit for Sunny Central 500HE-US/CA and SunnyCentralCP. . 31
6.2 Cable requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2.1 Cable requirements for DC, AC and PE connection . . . . . . . . . . . . . . . . . . . 32
6.2.2 Additional cable requirements for DC connection . . . . . . . . . . . . . . . . . . . . 32
6.3 Connecting DC cables to the Disconnect Unit . . . . . . . . . . . . . 33
6.3.1 Connection sequence DC switches 600V . . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.3.2 Connecting DC cables to DC load break switch with screw terminals . . . . . 34
6.3.3 Connecting DC cables to DC load break switch with cable lugs . . . . . . . . . 36
6.3.4 Connecting sequence for single DC load break switch, 600V . . . . . . . . . . 38
6.3.5 Connecting sequence for single DC load break switch, 1,000V. . . . . . . . . 39
6.4 Connecting AC cables to the Disconnect Unit . . . . . . . . . . . . . 40
6.4.1 Additional cable requirements for AC connection . . . . . . . . . . . . . . . . . . . . 40
6.4.2 Arranging AC cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.4.3 Overview AC connection to power distribution grid. . . . . . . . . . . . . . . . . . . 42
6.4.4 Overview AC connection to the inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6.4.5 Connecting AC cables to busbars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.5 Connecting protective earth . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.5.1 Additional cable requirements for PE connection . . . . . . . . . . . . . . . . . . . . . 53
6.5.2 Connecting protective earth to busbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.6 Closing the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.7 Affixing information about grounded path . . . . . . . . . . . . . . . . 58
7 Operating the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . 60
7.1 Arrangement of the switches. . . . . . . . . . . . . . . . . . . . . . . . . . . 60
7.2 Switching on the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . 61
7.3 Switching off the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . 62
7.4 Securing against reconnection – Lock-Off function. . . . . . . . . . 63
8 Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

SMA America, LLC Table of Contents
Installation Guide DisconACDC_SCUS-IUS103110 9
8.1 Disconnect Unit for Sunny Central 250U/500U . . . . . . . . . . . 65
8.2 Disconnect Unit for Sunny Central 500HE-US/CA. . . . . . . . . . 66
8.3 Disconnect Unit for Sunny Central CP. . . . . . . . . . . . . . . . . . . . 67
9 Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

SMA America, LLC
10 DisconACDC_SCUS-IUS103110 Installation Guide