User Manual

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Planning for a Three-Phase IQ Microinverter System – North America

Transformer Specification (Table of Various Voltage Configurations)

Utility voltage

configurations

Nominal voltages between the lines and neutral/ground

L1 to L2

L2 to L3

L3 to L1

L1 to N/G

L2 to N/G

L3 to N/G

208Y/120V

208

120

No transformer would be specified for interconnection

480Y/277V

480

277

Specify a 480 delta:208Y/120V transformer or 480 delta:240 high-leg delta transformer

480 delta

(*corner grounded)

480

Specify a 480 delta:208Y/120V transformer or 480 delta:240 high-leg delta transformer

240 delta

240

Install a 240V to 120/240V auto-transformer for powering the Envoy (Hammond 170 “Auto”)

240 high-leg delta

240

120

208

No transformer would be required for interconnection of IQ System

600Y/347V

600

347

Specify a 600 delta:208Y/120V transformer or 600 delta:240 high-leg delta transformer

Multiple IQ Envoys on a Single Site — Filtering Communication Domains

Enphase IQ Microinverter systems use power line communications (PLC) to communicate module level data

between the microinverters and the IQ Envoy. Each IQ Envoy can communicate with a maximum of 600 IQ

Microinverters. The PLC signal is at 110kHz in an IQ System. In a commercial scale system, the IQ Envoy is

continuously polling the microinverters for their recent power production, temperature, voltage, amperage,

and frequency data. To ensure good communication between the IQ microinverters and the IQ Envoy, install

power line filters or transformers to:

• Prevent cross-domain communications between multiple IQ Envoys.

• Minimize electrical noise at frequencies near 110kHz.

• Minimize the distances between the IQ Microinverters and the IQ Envoys.

When multiple IQ Envoys are on a single utility transformer, use a filter to isolate each IQ Envoy and its

associated microinverters from the other IQ Envoys and IQ Microinverters. This is particularly important for

large-scale projects.

In a large-scale project, each sub-system or communication domain generally consists of a single IQ Envoy,

a single panel board, a power line filter, and the branch circuits off that panel board. A filter prevents power-

line communication signals from one IQ Envoy communication domain from interfering with other

communication domains. The filter also eliminates electrical noise from site loads.

With multiple communication domains, the total number of filters can be one less than the total number of

communication domains. For example, if all other communication domains have filters, the last

communication domain can be installed without a filter (n – 1).

If the system contains fewer than 600 microinverters with a single IQ Envoy on-site (a single communication

domain), a filter is not required to isolate communication domains from each other, but may be used to

ensure a clean PLC environment free of electrical noise.

For sites with multiple IQ Envoys, the conductors and conduits of each communication domain must be kept

physically separated from the conductors and wiring of other communications domains by at least 12 inches.

Coupling of the signals can occur between the conductors and conduits when run together, especially on

long conduit and wire runs.