Solectria Renewables PVI 2500 User manual

PVI 1800/PVI 2500
INSTALLATION AND OPERATION MANUAL
Residential/Commercial
Grid-Tied Photovoltaic Inverter
© 2008, Solectria Renewables
Subject to Change REV A

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
2
DOCR-070570-A
IMPORTANT SAFETY INSTRUCTIONS
This manual contains important instructions that shall be followed during installation and maintenance of
the PVI 1800/PVI 2500 Inverter.
To reduce the risk of electrical shock, and to ensure the safe installation and operation of the inverter, the
following safety symbols are used to indicate dangerous conditions and important safety instructions.
WARNING: This indicates a fact or feature very important for the safety of the user
and/or which can cause a serious hardware damage if not applied appropriately.
Use extreme caution when performing this task.
NOTE: This indicates a feature that is important either for optimal and efficient use or
optimal system operation.
EXAMPLE: This indicates an example.
SAVE THESE INSTRUCTIONS

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
3
DOCR-070570-A
IMPORTANT SAFETY INSTRUCTIONS
 All electrical installations shall be done in accordance with the local and national electrical codes
ANSI/NFPA 70, NEC. The PVI 1800 and 2500 inverters are listed to UL1741/IEEE1547 (and
comply with IEEE 62.41).
 The PVI 1800/PVI 2500 contains no user serviceable parts. Do not open the inverter case as this
will damage the NEMA4, IP65 seal. Please contact Solectria Renewables or a Solectria
Renewables authorized system installer for maintenance. (See page 44 or Solectria Renewables
website, www.solren.com for Solectria Renewables contact information and authorized system
installers.)
 Before installing or using the PVI 1800/PVI 2500, please read all instructions and caution
markings in this manual and on the PVI 1800/PVI 2500 unit as well as the PV modules.
 Connection of the PVI 1800/PVI 2500 to the electric utility grid must be done after receiving prior
approval from the utility company and performed only by qualified personnel.
 Completely cover the surface of all PV-arrays with opaque (dark) material before wiring them or
use other methods to ensure safety from shock hazard. PV arrays produce electrical energy when
exposed to light and could create a hazardous condition.
SAVE THESE INSTRUCTIONS

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
4
DOCR-070570-A
Table of Contents
1 Introduction ................................................................................................................... 5
2 Installation ..................................................................................................................... 9
2.1 Checking for Shipping Damage ............................................................................ 9
2.2 Inverter Mounting ................................................................................................. 9
2.3 Electrical Connection and Connection to Electrical Utility Grid,
Surge/Lightning Arrestors and Grounding Electrode Conductors ........................ 14
3 Commissioning the Inverter and PV System ................................................................ 19
4 Power, Ground Fault, Error LED Indicators and LCD Display .................................... 21
4.1 Power, Ground Fault and Error LED Indicators ................................................... 21
4.2 The LCD Display .................................................................................................. 23
5 Trouble Shooting........................................................................................................... 30
6 Warranty........................................................................................................................ 33
6.1 Warranty Policy .................................................................................................... 33
6.2 Return Material Authorization Policy ................................................................... 36
7 Technical Data .............................................................................................................. 37
Appendices .................................................................................................................... 42
Appendix A: Terminal assignment RS 485 / RS232 .................................................... 42
Appendix B: PVI 1800 / 2500 Brochure / Datasheet ................................................... 43
Appendix C: Example PV String Sizing Tables .......................................................... 43
Appendix D: Contact Information & Authorized Dealers and Installers ..................... 44

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
5
DOCR-070570-A
1 Introduction
The PVI 1800/PVI 2500 is a residential/commercial single phase, grid-tied PV inverter designed to be
inter-connected to the electric utility grid. With this manual the PVI 1800/PVI 2500 can be installed and
operated safely. This installation guide is used as reference for the commissioning and as a guideline on
how to use the inverter most effectively.
Feeding power into the grid involves conversion of the DC-voltage from the PV-array to grid compatible
AC-voltage by “inverting” DC to AC. This unit feeds power into a standard 240 VAC split phase
electrical system or two legs (phase to phase) of a 208 VAC, 3-phase commercial, industrial or
institutional facility’s electrical system that is connected to the electric utility grid.
If the PV system and inverter are providing the same amount of electrical power that the facility is using
then no power is taken from or fed into the utility grid. If the facility is using more power than the PV
system is providing, then the utility grid provides the balance of power. If the facility is using less power
than the PV system is generating, then the excess is fed into the utility grid.
Be sure to look into local regulations regarding net metering/inter-connection in your local area. Note
that some utilities need to change their revenue kWh meter for proper net metering measurement or
incentives/billing.
Fig. 1 Grid tied inverter application
Photovoltaic
Array PVI 1800/PVI 2500
Inverter
Electric Utility
Grid

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
6
DOCR-070570-A
The string PV concept
The use of string PV concept significantly reduces the cabling costs on a photovoltaic system. The use of
just one, two (or in some cases 3) parallel strings of PV modules in series has proven advantageous by
delivering a high operating voltage to the solar inverter. This advantage is primarily reflected in a higher
efficiency of the inverter. Careful optimization of the overall inverter system’s cost and efficiency lead to
the choice of a 400V DC maximum system voltage for the PVI 1800 and 2500 for use with 1kW to 3kW
PV arrays per inverter.
Data acquisition, display and communication
The integrated data acquisition, display and communication capability of the PVI 1800/PVI 2500 allows
comprehensive tracking of data for understanding of system performance. All error messages and
operating conditions of the PVI 1800/PVI 2500 as well as the PV system can be shown on the display.
Downloading data from the PVI 1800/PVI 2500 for analysis on a PC is also possible over the data
interfaces (RS232 or 485).
These functions allow complete and continuous monitoring of the photovoltaic system. Read-out of data
over the integrated interface and its display is only possible when the solar system is in operation.
An optional full-featured, “inverter-direct” data acquisition and logging gateway and web-based service is
available from Fat Spaniel. You can purchase this from Solectria Renewables or Fat Spaniel. It plugs
into the inverter and to the facility’s internet service.
Technical structure of the PVI 1800/PVI 2500
A high frequency switching bridge circuit operating in connection with a high frequency transformer
provides galvanic isolation of the photovoltaic system from the building’s AC power (and electrical
utility grid). The PV voltage and current are optimized in such a way that fluctuations which are caused
by differing sunlight strengths and PV module temperatures can still end up producing the maximum
possible power.
Internal regulation of the PVI 1800/PVI 2500 is achieved using microcontrollers, which control the
function of MPP (Maximum Power Point) tracking.
The input PV voltage window is designed to cover a range of 125 to 400 VDC from the PV array. This
means that many combinations of modules and strings from different manufacturers can be used.
The inverter has nearly no standby power consumption and night–time losses (0.2 W). Even when
running, the control circuit power use of the inverter is reduced to a minimum, which helps give the
inverter high operational efficiency.
The housing and heat sink for the PVI 1800/PVI 2500 is manufactured using a heavy aluminium extrusion
with an anti-corrosion finish. The housing is designed to NEMA4 and IP65 to be dust-proof and resistant to
water spray. The heat sink (and fan on the PVI 2500) are designed in such a way that operation of the
inverter is possible at ambient temperatures of -4° F (–20° C) to +131° F (+55° C) at full rated power (at
240VAC or 208VAC).

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
7
DOCR-070570-A
The heat sink serves to conduct away heat generated from energy losses in the power electronics. Internal
temperature regulation provides protection against excessively high temperatures inside the PVI 1800/PVI
2500. The maximum power processed from the PV array is automatically reduced to limit excessive inverter
temperature.
The PVI 1800/PV2500 will only operate in parallel with the utility grid. AC grid monitoring is done by
microcontrollers set up to meet the requirements of UL1741/IEEE1547. This includes grid voltage or
frequency fluctuations outside of the required limits, anti-islanding and other limitations and requirements,
which ensure that the inverter shuts down immediately if the grid goes down, or if the grid gives surges, sags,
changes frequency or otherwise shows signs of instability. If this happens, the inverter will check the grid
and reconnect to the grid 5 minutes after the grid is back to normal. (The display then shows: “Waiting for
restart”.) Disconnecting from the grid is important to protect the electrical and utility line workers who may
be working to restore the grid as well as electricians working at a site with PV systems.
Power grid faults that will cause the PVI 1800/PVI 2500 to isolate itself from the power grid:
 AC grid voltage
The grid voltage must not go outside the range of +10/-12% of the nominal 240 or 208V AC grid
voltage (as per IEEE Std 1547, § 4.2.3). The inverter will isolate itself from the power grid if these limits
are exceeded either way. The PVI 1800/2500 is factory set to 208 or 240VAC. A qualified installer can
reconfigure the grid voltage setting in the field using a computer, Solectria provided software and an
available serial communication cable.
 AC grid frequency
The power grid frequency can be within a range of +0.5Hz, -0.7Hz of the nominal 60Hz grid frequency
(as per IEEE Std 1547, § 4.2.4). The inverter will isolate itself from the power grid if these permitted
limits are exceeded either way.
Another important safety feature is galvanic isolation of the utility grid and the PV array as well as ground
fault detection and interrupt (GFDI) of the PV array. The PV array negative is grounded inside the inverter
(and must not be grounded at any other point).

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
8
DOCR-070570-A
Diagram of the PVI 1800/PVI 2500 Features
Fig. 2 PVI 1800/PVI 2500 Features Diagram
(1) AC conduit fitting and conductors to building/grid (10 AWG, XHHW-2 wire) PV
(2) PV array ground fault interrupt (GFDI) fuse
(3) DC conduit fitting and conductors (10 AWG, XHHW-2 wire)
(4) Grounding Electrode Conductor connection point (on side of heat sink)
(5) Fan Connection (used on PVI 2500)
(6) RS-232/485 communication ports and caps
(7) LCD display and key pad
(8) LED indicators for basic operating status
(9) Fan assembly (on PVI 2500 only)
(10) Inverter Serial Number on bottom plate
9
8
7
6
1
2
4
5
3
10

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
9
DOCR-070570-A
2 Installation
WARNING: Before installing the PVI 1800/PVI 2500, read all instructions and caution
markings in this manual and on the PVI 1800/PVI 2500 as well as on the photovoltaic
modules.
WARNING: Electrical installation shall be done in accordance with all local electrical
codes and the National Electrical Code (NEC), ANSI/NFPA 70.
WARNING: Connecting the PVI 1800/PVI 2500 to the electric utility grid must only be
done after receiving prior approval from the utility company and installation completed only
by qualified personnel/licensed electrician(s).
2.1 Checking for Shipping Damage
The PVI 1800/PVI 2500 inverters are thoroughly checked and tested rigorously before they are shipped.
Even though they are delivered in a rugged, heavy cardboard box, the inverters can be damaged in
shipping which is typically the fault of the shipping company.
Please inspect the inverter thoroughly after it is delivered. If any damage is seen please immediately
notify the shipping company. If there is any question about potential shipping damage, contact Solectria
Renewables. A photo of the damage may be helpful.
Do not accept unit if visibly damaged or note visible damage when signing shipping company receipt.
Report damage immediately to the shipping company. Do not remove the unit from packaging. If it is
determined that the unit must be returned, an RMA# must be obtained from Solectria Renewables.
2.2 Inverter Mounting
The PVI 1800/PVI 2500 inverter is made up of a sealed NEMA 4 /IP65 corrosion resistant aluminum
enclosure containing all electrical and electronic components.
NOTE: If the PVI 1800/PVI 2500 is mounted outside, make sure the mounting & wiring is
completed, at least to the AC and DC disconnects or junction box(es) in case of rain during
the installation process (for example overnight rain). Since the AC and DC connections are
wired to the disconnects and or junction box(es) only, there is no need to open the inverter
enclosure during hook-up. The inverter enclosure is factory sealed and must NOT be opened
at any time in the field or the NEMA4, IP65 seal will be compromised and this will void the
warranty.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
10
DOCR-070570-A
Notes regarding mounting and placement of the inverter
Criteria for device mounting:
 Because the inverter is in a NEMA4/IP65 sealed enclosure, the inverter can be mounted outdoors.
 The very longest life for the inverter can be achieved by mounting it in a clean, dry and cool location
even given the unit’s robust construction and design for efficient cooling. It is recommended to keep
the unit out of direct rain.
 For optimal electrical efficiency, use the shortest possible AC and DC wires and use the maximum
allowable wire size. (10AWG minimum is recommended for all connections, both AC and DC.)
 Avoid installation in close proximity to people or animals, as there is a small amount of high-
frequency switching noise.
 Install the inverter in an accessible location following NEC and local codes. Note NEC requirements
for disconnect door clearances and proximity to other equipment and building walls.
 Although not required, installation at eye-height allows easy reading of the indicator LEDs and the
LCD display.
 For optimal inverter life and performance, do not mount the inverter in direct sunlight, especially in
hot climates, although the inverter is designed to function at full power continuously in up to 131o F
(55o C) ambient temperatures. In hot climates if the unit must be mounted in direct sunlight a silver
or white metal sun-shield is highly recommended. It is recommended that the inverter be mounted on
the north (or east) side of buildings or on the north side of a PV array (which can provide some
shade). Following these guidelines can help prevent the unit from going automatic into de-rating due
to excessively high inverter case temperature.
 In hot climates, the housing and heat sink can reach 176o F (80
o C) and must be mounted on an
appropriate material for this temperature as well as one that meets NEC and local codes. The inverter
should not be mounted where people are likely to touch the case or heat sink due to the high potential
temperature.
CAUTION: Please follow these guidelines:
 The inverter weight is about 35 lbs. (16kg). Be sure method used for fastening the unit to the wall
will safely hold this weight.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
11
DOCR-070570-A
 The ambient temperature must be between –4o F (–20o C) and +131o F (+55o C) for full continuous,
full power operation. (The inverter will automatically reduce power or shut down to protect itself if
the ambient air temperature rises above 131o F (55o C).)
 The National Electrical Code (NEC) requires that the inverter be connected to a dedicated AC circuit
and no other AC outlets or device may be connected to this circuit. See NEC Section 690.64. The
NEC also imposes limitations on the size of the inverter and the manner in with it is connected to the
utility grid. See NEC Section 690.64.
 The cooling air enters at the bottom and exhausts at the top of the unit.
 A minimum distance of 6 inches (152mm) must be clear above and below the inverter for ventilation.
 The inverter must be mounted directly on a flat (wall) surface. (Do not mount to open studs or any
horizontal or vertical beams or struts as this can hinder proper cooling performance). The inverter
must be mounted vertically (see mounting photos).
 If you are installing the inverter in a utility vault or electrical closet, the air circulation must be
sufficient for heat dissipation – provide external ventilation, to maintain an ambient condition of less
than 131o F (55o C). The ambient temperature should be kept as low as possible.
 See photo and use dimensional diagrams for correct mounting of the inverter.
Painted plywood board in basement (BPVS)
Typical mounting on plywood board (Sunlight Solar) Optional panel assembly available
Fig. 3 How to mount the inverter
Optional double panel assembly available

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
12
DOCR-070570-A
Fig. 4 PVI 1800/PVI 2500 Dimensional Diagram

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
13
DOCR-070570-A
Fig. 5 PVI 1800/PVI 2500 Mounting Screw Pattern
Mounting Details
Using the mounting diagram Fig. 5, for screw positions on, wall. Four #10 or #12 screws can be used.
It is recommended to use stainless steel screws, especially if used outdoors. Be sure to verify sheer and
pullout strength of anchors or other wall attachments.
NOTE: Always use all 4 mounting screws. It is easiest to layout the 4 screw mounting
pattern using Fig. 5, pre-install the 4 screws, backed out about 1/8-3/16” from the wall
surface, install the inverter, then tighten the screws. The square mounting pattern for the
screws is about 12-5/8” x 12-5/8”. A cardboard template is also included in the box with
the inverter.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
14
DOCR-070570-A
NOTE: The inverter is set up with pre-wired AC and DC connections to make it very easy
and quick to connect to a DC disconnect to the left of the inverter and an AC disconnect to
the right. (Connections can also be made to junction boxes.)
2.3 Electrical Connection and Connection To Electrical
Utility Grid
Fig. 6 Simplified electrical connection diagram
Location and Mounting the Inverter
NOTE: Choose the inverter location keeping in mind where the disconnects, and/or
junction boxes and kWh meter (if needed) will be located. It is best to mark on the wall
(or create a diagram) where all of the components are to be located. The inverter is set up
with pre-wired AC and DC connections to make it very easy and quick to connect to a
DC disconnect to the left of the inverter and an AC disconnect to the right.
Refer to Figure 2 for Locations of Features, AC and DC Wires, etc.
WARNING: All electrical installations shall be done in accordance with all local electrical
codes and the National Electrical Code (NEC), ANSI/NFPA 70.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
15
DOCR-070570-A
The negative DC photovoltaic connection is grounded within the inverter through the ground fault
detection and interrupt circuit (GFDI). The PV negative should not be grounded at any other
point in the system. The PV positive must never be grounded at any time.
AC and DC (PV) Connections:
The PVI 1800 and PVI 2500 inverters are pre-wired with 54” (1.35 meter) wires for both the DC (PV)
input and the AC connection to the building/grid (so that a 48” long conduit can be used leaving 6” of
conductors available for connection in the disconnect, junction box, etc.). The units are also equipped
with conduit fittings that are NEC code-compliant for use with both metallic and non-metallic flexible
1/2” conduit (the conduit fittings are included on the unit as well as the wires but the conduit needs to be
added during installation). This design allows installation and wiring of the inverter to be done without
opening the inverter.
Lightning and Surge Protection:
The inverter is designed with certain protections against surges in voltage including certification to
UL1741/IEEE1547 (including ANSI/IEEE 62.41/62.42 as required in the NY SIR), however added
protection and solid grounding provisions are important for best protection against utility surges and
surges created by indirect lightning strikes.
The installation of a Delta lightning surge arrester or other UL listed arrester of the correct specification is
recommended on both the DC and AC sides of inverter. This can be installed on the outside of the DC
disconnect and wired using the manufacturer's directions. This device gives important added protection
from indirect lightning strikes and resulting surges that provide protection beyond the inverter's UL1741
requirements. It is suggested to drive a ground rod specifically for the PV array. It is also a very good
idea to have the lightning protection system of the building checked and upgraded if needed before the
PV system is installed. (are there air conductors along the roof line of the building above the PV array?
Do you see a copper ground wire running from the air conductors to a ground rod?) These added
protections are especially important for areas prone to thunder storms and possible nearby lightning
strikes. Although these added precautions will not guarantee that there will be no damage from lightning,
they can help prevent or limit potential damage.
Grounding Electrode Conductor:
As with all PV systems, a Grounding Electrode Conductor must be installed per NEC690.47 (and
250.166). This conductor should be sized according to these NEC requirements. This conductor should
be terminated on the labeled ground point located at the bottom end of the left heat sink fin. A ¼-20
stainless steel hex cap screw should be used with an appropriate ground lug.
WARNING: The inverter should not be opened at any time. The unit is sealed at the factory
and its UL listing will no longer be valid and the warranty will be void if opened, as the seal
cannot be guaranteed.
AC Voltage:
The PVI 1800 and PVI 2500 are both 240V AC grid connected devices. They are also both suitable for
208V AC grid-connected use. For example, connection to 2 phase legs of a 208V AC, 3-phase service
(where acceptable by code). Neither unit (PVI 1800 or PVI 2500) can be used with a 120V AC
connection and no neutral connections can be made to the inverters. The units are factory pre-set for
240VAC unless ordered as a 208VAC unit. Also software and a cable are available for use by a qualified
installer to change the setting to whichever voltage is required. A PC must have a 9-pin “D” RS-232 port.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
16
DOCR-070570-A
Multiple Units:
Multiple PVI 1800 or PVI 2500 units can be used at the same location/facility assuming all codes are
followed including NEC, local building codes and area utility guidelines. If multiple units are used, each
inverter should have its own dedicated circuit breaker, and a PV string must only be wired to one inverter
(although multiple PV strings can be used on each inverter up to unit ratings and power levels).
AC Circuit Breakers:
A dedicated AC circuit breaker in the home or building circuit panel is required for the PV inverter. For
both the PVI 1800 and PVI 2500, a 15 Amp, 208/240V AC rated 2–circuit breaker is required.
AC and DC Disconnects:
It is recommended that the PV system AC and DC disconnects be located beside the inverter if possible
but must conform to local code for your installation. This placement will make the best use of the “pre-
wired” inverter feature and save installation time, material and effort as well as making a simple, reliable
system. If local code requirements call for the AC and/or DC disconnect(s) to be mounted in another
location, you can consider relocating the inverter also to the required location or add a small junction box
or termination box to connect the PVI wires to building wiring going to disconnect location(s). Fig. 7
shows a typical installation with the AC and DC disconnects located on either side of the inverter.
Fig. 7 A typical PVI 1800 or PVI 2500 installation with AC and DC disconnects. (AC disconnect is
on the right, DC disconnect on the left. PVI 2500 shown.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
17
DOCR-070570-A
Suggested AC Disconnect: 240V AC, 30A, 2 Blade, NEMA 3R
Part Number Manufacturer
Rain-proof NEMA 3R, no fuse DU22IRB Square D
Rain-proof NEMA 3R, fusible
Rain-proof NEMA 3R, no fuse
TG3221R
TGN3321R
GE
GE
Pull-out disconnect, 3R, no fuse 3800 Millbank
For some installations, code compliance may include indoor, NEMA 1 rated disconnects which are less
expensive. For whichever disconnect is selected, you will also need the proper listed ground bar kit. (No
neutral kit is needed, as no neutral line should enter the disconnect.)
Connecting the AC Inverter Wire:
WARNING: The wiring of the PV inverter’s AC and DC wires must only be done with the
building AC circuit breaker off and the PV array disconnected or covered with an opaque
material (or other method to assure the PV wiring is not live). Both AC and DC disconnects
should be off.
If the connection of the AC wires that are provided on the inverter is to be made to an AC disconnect or
junction box, mount the disconnect or junction box. (Make sure the disconnect or junction box is close
enough to the inverter so that the inverter wires will reach the disconnect or junction box via a conduit
and so that an adequate length of wire will be available inside disconnect or junction box to make the
connections/terminations to the L1, L2 and ground point.) As shipped, the conduit fittings included on
the inverter have the wires but no conduit in them. The conduit is to be fitted during installation.
Measure and cut the 1/2” liquid-tight metallic or non-metallic flexible conduit to connect between the
inverter’s AC conduit fitting and the disconnect or junction box. Next, install conduit fitting on the
disconnect or junction box. Thread the inverter’s AC wires through conduit and into disconnect or
junction box conduit fitting. Fit the conduit into the conduit fittings on inverter and disconnect or
junction box and tighten. If needed, cut off the inverter AC wires to correct length(s) inside the
disconnect or junction box. Finally, terminate inverter wires in disconnect or junction box. Black wires
are L1 and L2. Green is the AC equipment ground.
Connection Wiring To Electrical Utility Grid And Grid Impedance:
The PVI 1800/PVI 2500 must be connected to the grid with 2 conductors and a ground wire.
The grid impedance value at the connection point should be as low as possible to avoid an increase of the
AC-voltage to non-permissible values while the inverter feeds to the grid. Minimizing wiring impedance
also results in higher system efficiency.
EXAMPLE: The impedance is the sum of the electricity grid impedance at building
distribution and all impedance values of conductors and connections.
Single conductor impedance values are:

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
18
DOCR-070570-A
 Approximately 0.40 Ω for a 100 feet (76.2 m) 12 AWG conductors
 Approximately 0.24 Ω for a 100 feet (76.2 m) 10 AWG conductors
 Approximately 0.15 Ω for a 100 feet (76.2 m) 8 AWG conductors
 Conductor impedance of < 0.40 Ω is recommended
The total impedance phase to phase of the grid plus the interconnecting AC conductors should be less
than 1.2 Ω.
Suggested DC Disconnects: 600V DC, 30A, 1-3 Circuits
Part Number Manufacturer
Rainproof NEMA 3R HU361RB Square D
3 circuit, fused version H361RB Square D
Rain proof NEMA 3R THN2261RDC GE
For some installations code-compliance may include indoor, NEMA 1 rated disconnects which are also
available (typically less expensive). Also, for lower power/lower voltage configurations in which the
maximum OCV (Open Circuit Voltage) of the PV array in cold weather extremes is less than 250V DC,
per NEC690-7 (1.25X PV OCV, for example) it may be adequate to use 250V DC rated disconnects as
well.
The PVI 1800 and PVI 2500 inverters are not capable of back-feeding currents into the PV array from the
AC source including into short circuit(s) or fault(s) in the PV array or string(s). This allows some
flexibility regarding PV string configurations including parallel strings with and without string fusing. If
string fusing is required, for example on a large 2-3 string system, the fused H361RB disconnect can be
used. No separate fused PV combination is required. Refer to Square D Data Bulletin 3136DB0301
5/2003 for information. There are many one and two string configurations that do not need fusing.
PV String Configurations:
There is a huge number of PV module string combinations that will work well with the PVI 1800 and PVI
2500 inverters given the very large DC voltage range in which the inverter can operate. See string sizing
in Appendix C for several examples.
Connecting the DC (PV) Inverter Wire:
WARNING: Follow PV module manufacturer’s directions. PV-arrays produce electrical
energy when exposed to light and could create a hazardous condition. (One method used to
assure safety from shock is to completely cover the surface of all PV-arrays with opaque /
dark material before wiring them.)
WARNING: Before connecting the connectors of the PV-panel to the DC disconnect
enclosure and before connecting the DC inverter wire, check the correct polarity and
admissible PV-panel voltage between the (+) and the (-) cable connectors of the PV panel.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
19
DOCR-070570-A
The PV-panel open circuit voltage must be below 400V DC (Vpv < 400V DC) under all
conditions as per NEC 690-7 using multiplier for cold weather OCV. Please read the
Technical Info section and see PV string sizing table in Appendix C.
WARNING: Even when in the off position, the DC disconnect will remain live on the PV
side (“line”) when the PV modules are in daylight.
If the connection of the DC (PV) wire provided on the inverter is to be made to a DC disconnect or
junction box, mount the DC disconnect or junction box. (Make sure the disconnect or junction box is
close enough to the inverter so that the inverter’s DC wires will reach the disconnect or junction box via a
conduit and that an adequate length of wire will be available inside the disconnect or junction box to
make connections/termination to positive (+) switched terminals, negative (-) PV wire, and ground bar. It
may be convenient to use a neutral kit for terminating multiple PV negatives.)
The conduit fittings included on the inverter are open, as shipped (although the wires are inside conduit
fittings, they have no conduit in them). Measure and cut the 1/2” metallic or non-metallic flexible
conduit to go between the inverter’s DC conduit fitting and the DC disconnect or junction box. Next,
install a conduit fitting in the DC disconnect or junction box. Thread the inverter’s DC wires through the
conduit and into the DC disconnect or junction box conduit fitting. Fit the conduit into fittings and tighten
fittings. If needed, cut off inverter’s DC wires to the correct length inside the DC disconnect or junction
box. Finally, terminate inverter wires in the DC disconnect or junction box. Red wire is positive (+),
white is negative (-) and green is ground.
3 Commissioning the Inverter and PV System
The inverter is mounted, all connections are made and you are ready to power it up.
NOTE: Make sure all tools; parts, etc. are removed from the vicinity of the inverter before
turning on.
WARNING: Make a final check for correctness of all AC and DC wiring to the inverter
and in the system.
NOTE: With the PV modules connected and inverter disconnects still off, it is a good
precaution to check PV polarity once more simply by carefully using a 600V, DC rated
digital volt meter and probing the positive (+) and negative (-) PV connections in the
disconnect.

PVI 1800/PVI 2500(Rev A) Installation and Operation Manual
20
DOCR-070570-A
Turning on the inverter:
 Turn on the dedicated 2-circuit 240/208VAC circuit breaker on the home/building electrical panel
 Turn on the AC disconnect
 Turn on the DC disconnect
 Watch the LED indicators for initialization (all three LEDs on)
 Watch for blinking green LED and high frequency switching sound (this means that the inverter is
on-line and beginning to feed power into the AC circuit), the inverter is operating normally
 Last, look for a steady green LED indicating the inverter has stabilized at Maximum Power Point
Operation:
The control electronics will be active as soon as DC (PV) voltage reaches 125V DC. The inverter will go
on-line with the utility/building grid when the DC voltage first exceeds 150V DC. Next, the inverter will
load the array, bringing the DC voltage down from 150V DC to no less than 125V DC.
Once there is enough PV power at 125V DC to back feed AC power switching will automatically feed
power to the grid.
Because the inverter goes completely off line at night or in dark conditions when no power can be
produced, the standby losses are less than 0.25 Watt, adding 1-2% additional energy production annually
compared to some competitor’s inverter designs that remain on all the time.
Operating states, GFDI status and error indications shown by the LED indicators, an extensive data is
shown by the LCD display which are described in chapter 4, “Power, GFDI, Error LED Indicators and
LCD Display”.
4 Power, Ground Fault, Error LED Indicators and LCD Display
The inverter operates automatically without the need for user interaction or maintenance.
The PVI 1800/PVI 2500 automatically starts feeding AC power into the grid every morning as the sun
rises, as soon as sufficient DC voltage and PV power is available. The inverter microcontroller runs
through various checks before going online with the grid and feeding power into the grid.