User's Manual

P a g e | 7
BEFORE INSTALLATION
Review and follow the instructions in this section before installing UBIQUITI SM-MI-250 micro inverters .
Layout PV System
The optimal PV array layout will need to be planned before installation. The layout/plan will affect the wiring and
cabling schemes and will need to be adjusted accordingly. The layout will also need to account for the constraints
of the distance between each PV module due to the cable length. Please complete reading this user manual before
installing the system.
Compatibility and Capacity
UBIQUITI SM-MI-250 micro inverters are electrically compatible with PV modules that have a voltage range of 22 ~
36V and a maximum input power of 300W. For more information, refer to the Technical Specifications section on
page 16.
For a list of electrically-compatible PV modules and racking systems, refer to the UBIQUITI website at
www.UBIQUITIsolar.com. Before ordering the PV module connector, make sure the connector type is compatible
with both the micro inverter and PV module.
Electrical Compatibility
Model PV MPPT Voltage Range PV Module Connector Type
SM-MI-250 22V ~ 36V MC-4 Locking
Voltage and Capacity
Maximum number of SM-MI-250s per AC Branch Circuit Over current Protection
240V with 12AWG AC Trunk Cable 12 20Amp Breaker
WARNING!
DO NOT exceed the maximum number of micro inverters in an AC branch circuit as listed above.
WARNING!
Each AC branch circuit must be protected by a dedicated circuit breaker of 30A or less if using 10 AWG
trunk cable, or 20A or less if using 12 AWG trunk cable.
Utility Service Requirements
The M215 Microinverter works with split phase 240 VAC service only. Measure AC line voltage at the electrical
utility connection to confirm that it is within the ranges of 211 ~ 264V.
Lightning Surge Suppression
Lightning does not actually need to strike the equipment or building where the PV system is installed to cause
damage. Often, a nearby strike will induce voltage spikes in the electrical grid that can damage equipment.
UBIQUITI’s micro inverters (SM-MI-250) have built-in integral surge protection, which is much higher than
traditional inverters. However, if the surge has sufficient energy, which exceed built- in protection limits then the
device could potentially be damaged. As UBIQUITI’s limited Warranty does not cover “extraordinary and
unexpected manifestation of the forces of nature,” such as lightning strikes, it is recommended to install surge
protection as part of any solar installation. We recommend the following protection devices, which have been
tested to ensure that they do not interfere with power line communications. Please install as per manufacturer’s
instructions: