Installation manual

Safety, Installation, and Operations Manual

Power Unlocked by Design

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 sufcient 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 sufcient 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 COMMERCIAL

y Citel DS72-RS-120 surge protector; data sheet

y Delta LA-302 lightning arrestor; website

y Midnite solar surge protection device MNSPD-300 or

MNSPD-300FM (with ush mount box); website

y Citel DS73-RS-G surge protector; data sheet

y Delta LA-303 lightning arrestor; website

NOTE: Protection against lightning and resulting voltage surge

must be in accordance with local standards.