enphase IQ7 - Branch Circuit Capacity; Utility Service Requirements; Wire Lengths and Voltage Rise

IQ7/IQ7+/IQ7X/IQ7A Microinverters Installation and Operation Manual
13 © 2023 Enphase Energy Inc. All rights reserved. September 2023
IOM-00028-1.0
2.3 Branch circuit capacity
Plan your AC branch circuits to meet the following limits for a maximum number of microinverters per
branch when protected with a 20 A (maximum) over current protection device (OCPD).
Maximum* IQ7 Series Microinverters per AC branch circuit
Breaker IQ7 IQ7+ IQ7X
IQ7A
240 VAC 16 13 12
11
208 VAC 13 11 10
11
*Limits may vary. Refer to local requirements to define the number of microinverters per branch in your area.
2.4 Utility service requirements
The Enphase IQ Series Microinverters work with single-phase service. Measure AC line voltages at
the electrical utility connection to confirm that it is within the range shown in the following table.
240 VAC, single phase
L1 to L2
211 to 264 VAC
L1, L2 to ground
106 to 132 VAC
208 VAC, single phase
L1 to L2
183 to 229 VAC
L1, L2 to ground
106 to 132 VAC
NOTE: All 208 VAC installations require that you use the IQ Gateway to commission the
Enphase microinverters to propagate correct grid profile settings for 208 VAC trip points.
2.5 Wire lengths and voltage rise
Select the appropriate AC conductor size to minimize voltage rise when planning the system. Select
the correct wire size based on the distance from the microinverter AC branch circuit's beginning to
the load center breaker. Enphase recommends a voltage rise of less than 2% for the sections from the
microinverter AC branch circuit to the breaker in the load center.
Enphase provides guidance about choosing wire size and maximum conductor lengths in the Voltage
Rise Technical Brief at enphase.com/support. Refer to this brief for voltage rise values in IQ Cables
and how to calculate voltage rise in other wire sections of the system.
Standard guidelines for voltage rise on feeder and AC branch circuit conductors might not be
sufficient for microinverter AC branch circuits that contain the maximum allowable microinverters.
This is due to the high inherent voltage rise on the AC branch circuit.
Best practice: Center-feed the branch circuit to minimize voltage rise in a fully-
populated branch. This practice greatly reduces the voltage rise as compared with an
end-fed branch. To center-feed a branch, divide the circuit into two sub-branch circuits
protected by a single OCPD. Using the IQ Aggregator is a convenient way to do this.