Wire Lengths And Voltage Rise; Lightning And Surge Suppression - enphase IQ 7 Installation And Operation Manual

Wire Lengths and Voltage Rise

When planning the system, you must select the appropriate AC conductor size to minimize voltage rise.
Select the correct wire size based on the distance from the beginning of the AC branch circuit to the
breaker in the load center. Enphase recommends a voltage rise total of less than 2% for the sections from
the 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 Enphase
Q Cables and on 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 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.

Lightning and Surge Suppression

Enphase Microinverters have integral surge protection greater than most traditional inverters. However, if
the surge has sufficient energy, the protection built into the microinverter can be exceeded, and the
equipment can be damaged. For this reason, Enphase recommends that you protect your system with a
lightning and/or surge suppression device. In addition to having some level of surge suppression, it is also
important to have insurance that protects against lightning and electrical surges. Enphase has tested the
devices in the following tables.
Residential
•
Citel DS72-RS-120 surge protector; data sheet
•
Delta LA-302 lightning arrestor; website
•
Midnite solar surge protection device MNSPD-300 or
MNSPD-300FM (with flush mount box); website
NOTE: Protection against lightning and resulting voltage surge must be in accordance with
local standards.
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© 2021 Enphase Energy Inc. All rights reserved.
IQ Microinverter for ACM Applications
Commercial
•
Citel DS73-RS-G surge protector; data sheet
•
Delta LA-303 lightning arrestor; website
January 06, 2021