Ubiquiti MICROINV250W Users Manual

SM

INSTALLATION

MICROINVERTER

and OPERATION USER

MANUAL

UBIQUITI

-MI-250

P a g e | 1

PVP-0001 Ver1.2
Contact Information

2580 Orchard Parkway
San Jose, CA 95131

http://www.ubnt.com/contact/
[e-mail]
[e-mail]

FCC Compliance

Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this
device must accept any interference received, including interference that may cause undesired operation.

Warning: Changes or modifications to this unit not expressly approved by the party responsible for
compliance could void the user authority to operate the equipment.

Other Information
Product information is subject to change without notice. All trademarks are recognized as the property of their
respective owners.
To comply with FCC RF exposure compliance requirements, a separation distance of at least 20 cm must be

maintained between the antenna of this device and all persons. This Transmitter must not be co-located or
operating in conjunction with any other antenna or transmitter

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference in a residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television reception,
which can be determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:

—Reorient or relocate the receiving antenna.
—Increase the separation between the equipment and receiver.
—Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
—Consult the dealer or an experienced radio/TV technician for help.

P a g e | 2

Contents

IMPORTANT SAFETY INFORMATION ......................................................................3

Safety Symbols ..................................................................................................................................... 3

Safety Instructions ................................................................................................................................ 3

ABOUT UBIQUITI MICRO INVERTERS ....................................................................5

General Overview ................................................................................................................................. 5

Advantages of UBIQUITI Micro Inverters ............................................................................................ 5

TECHNICAL SPECIFICATIONS ................................................................................................................ 6

BEFORE INSTALLATION ..............................................................................................7

Layout PV System ................................................................................................................................. 7

Compatibility and Capacity .................................................................................................................. 7

Utility Service Requirements ............................................................................................................... 7

Lightning Surge Suppression ................................................................................................................ 7

AC Cable terminal connector ............................................................................................................... 8

UBIQUITI SM-MI-250 INSTALLATION PROCEDURE ..........................................9

Important Notification.....................................................................................................14

GFDI fault ............................................................................................................................................ 14

Disconnecting a Micro Inverter .......................................................................................................... 14

P a g e | 3

IMPORTANT SAFETY INFORMATION

READ THIS FIRST & SAVE THESE INSTRUCTIONS.

This manual contains important instructions for the installation and maintenance of UBIQUITI SM-MI-250 micro
inverters. Before installing, please read these safety instructions specifically. Take special care to follow the
warnings indicated on the unit itself as well as the safety instructions listed below.

Safety Symbols

To reduce the risk of injury and to ensure the continued safe operation of this product, the following safety
instructions and warnings are marked in this manual.

DANGER!
This indicates the risk of electric shock. The presence of high voltage levels may constitute to injury or
death to users and/or installers.

WARNING!
This indicates important information where failure to comply may result in safety hazards or cause
damage to this product.

Safety Instructions

Read all instructions and cautionary marks in the manual carefully before starting the installation.

DANGER!
Do not tamper or open this product. Opening this product may result in electric shock and void product
warranty.

DANGER!
Do not attempt to repair this product; it does not contain user-serviceable parts. Repairs and internal
servicing should only be performed by UBIQUITI authorized service personnel.

DANGER!
Perform all electrical installations in accordance with all applicable local electrical codes and the National
Electrical Code (NEC), ANSI/NFPA 70.

WARNING!
Only qualified electrical personnel should perform the electrical installation and wiring of this product.

WARNING!
Be aware that even without an external voltage source connected, the SM-MI-250 micro inverter may
contain high voltages and there is a risk of electrical shock.

WARNING!
Connect the UBIQUITI micro inverter to the utility grid only after receiving prior approval from the
electrical utility company.

WARNING!
The temperature of heat sinks outside of the device can reach over 85°C in normal operation. To avoid
human body burns, use caution while servicing micro inverters.

DANGER!

Do not disconnect the DC power source from the UBIQUITI micro inverter without first disconnecting the
AC power source. Both AC and DC power sources must be disconnected before servicing. Be aware that
DC power/voltage is generated when the photovoltaic array is exposed to light.

WARNING!

Switch off the circuit breakers before installation and wirings.

DANGER!

For safety remove all conductive jewelry or equipment during the installation or service of the device
parts, connector and/or wiring.

WARNING!

Do not stand on a wet location while doing installation and wirings.

WARNING!

Enclose the outer covering well before switching on the circuit breakers.

WARNING!

SM-MI-250 inverters should be installed as instructed in this manual. Failure to comply with these
precautions or with specific warnings elsewhere in this manual violates safety standards of design,
manufacturing, and intended use of the device. The manufacturer holds no liability for customer’s failure
to comply with these precautions.

WARNING!

When a GFDI (Ground fault) fault occurs, the LED will blink orange and red light alternately. Please
refer to page 15 for more introductions.

This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to
the following two conditions: (1) this device may not cause interference, and (2) this device must
accept any interference, including interference that may cause undesired operation of the device.

P a g e | 4

Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts
de licence. L'exploitation est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas
produire de brouillage, et (2) l'appareil doit accepter tout brouillage radioélectrique subi, même si le
brouillage est susceptible d'en compromettre le fonctionnement.

P a g e | 5

ABOUT UBIQUITI MICRO INVERTERS

General Overview

Thank you for choosing UBIQUITI’s SM-MI-250 micro inverters as a key component in your solar power system.
SM-MI-250 converts DC power (generated by the solar module) to AC power (powers your home appliances). The
UBIQUITI micro inverter is installed on the back of each solar module; and connects directly to the electric utility
grid without the need for a string or central inverter. The AC output from SM-MI-250 micro inverter is
synchronized and in-phase with the frequency range and voltage of the electric utility grid.

Advantages of UBIQUITI Micro Inverters

Optimal Energy Harvest – UBIQUITI’s micro inverters maximize the power produced from your Photovoltaic (PV)
array. Every PV module in solar system having its own inverter means having its own separate MPPT. Maximum
Power Point Tracking (MPPT), which monitors performance and maximizes the power harvested from each solar
module under varying environmental conditions. Sometimes performance of an individual PV module may be
affected by module mismatch, shading caused by trees or chimneys, or obstructions from leaves and other debris,
with separate MPPT of each module, if the performance of an individual PV module is reduced due to shading, the
overall production from the entire array is not affected, only the production of the individual PV module that is
being shaded will get affected. This typically results in improved power harvest of up to 20% from the solar PV
systems operated by string inverters, which represents significant cost/performance advantages.

Improved Safety – UBIQUITI micro inverters convert DC power to AC at module level; thus, eliminating the need
for high voltage DC wiring and making the solar system intrinsically safer. By eliminating DC wiring, specialized DC
practices and equipment are not required for installation. And arching problems which are associated with
string/traditional inverters are not involved.

Increased Lifetime and Reliability – UBIQUITI micro inverters are more reliable and have a longer life cycle than
the traditional string or central inverters. Typically, string/central inverters will need to be replaced at least once
over the lifetime of the solar module adding significantly to the overall cost of the solar PV system. UBIQUITI’s
solar micro inverters are designed to operate in real world conditions and achieve a peak efficiency of 95.7% at
temperature ranging from -40°C (45°F) and 65°C (150°F) without degradation of performance. The micro inverter
fully potted housing is designed for outdoor installation and complies with the NEMA 6 environmental enclosure
rating standards.

Enhanced Monitoring System – UBIQUITI’s enhanced monitoring system can view the performance of each
module in the PV array, a capability not available with string inverters. This provides users/installers with detailed
real-time information that can be used to pinpoint the location for performance issues and provide guidance for
maintenance, ensuring the solar system’s performance is optimized over the lifetime of the installation.

Simplified PV Array Design and Installation – With UBIQUITI micro inverters, the PV array design and installation
can be simplified because solar modules can be installed at any available space on rooftops. With conventional
inverters, the PV array design and installation are generally more complicated due to the effects shading has on
the overall performance of the PV array. When using UBIQUITI micro inverters, installers do not need to match the
performance levels of adjacent solar modules to optimize the performance of the entire array. Integrated
grounding also makes UBIQUITI solar installations easier, faster and cheaper to implement.