joule Pulsa PV, Installation Manual

22

Locating the Unit

Step 2 – Install the AC Branch Circuit Junction Box

Risk of Electrical Shock. 

•  Be aware that installation of this equipment includes risk of electric shock. Do not 

install the AC junction box without first removing AC power from the Enphase Sys-

tem.

•  Use electrical system components approved for wet locations only. 

•  When stripping off the Engage Cable sheath, make sure that the conductors are not 

damaged.

•  Loose cables might become a tripping hazard. Dress the Engage Cable to minimize 

this potential.

•  Do NOT exceed the 17 Microinverters in an single phase AC branch circuit, and 

protect each Microinverter AC branch circuit with a 20 A maximum breaker (or in 

accordance with local installation code).

•  Size the AC cable/wire size to account for voltage drop. Select conductor diameter 

based on the distance from the beginning of the Microinverter AC branch circuit to 

the breaker in the AC mains.

•  All components of system wiring must be considered, including internal voltage 

drop within the length of Engage Cable. Typically, three wire sections and several 

wire  terminations  must  be  quantified.  There  is  also  some  resistance  associated 

with each circuit breaker. As all of these resistances are in series, they add together. 

Since the same current is flowing through each resistance, the total voltage drop is 

total current times the total resistance. 

•  For a single-phase system, the total resistance is equal to two times the one-way 

resistance. For a three-phase system, each of the three line currents and resist-

ances must be calculated.

Standard guidelines for voltage drop 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.

•  Install an outdoor rated, weather-proof AC junction box at a suitable location on the 

mounting rail (typically at the end of a row of PV modules).

•  Provide an AC connection from the AC junction box back to the electrical utility 

connection, using equipment and practice as required by local standards.

•  Enphase  Microinverters  are  designed  to  operate  phase-to-neutral.  When  multi-

ple phases are present at sites with single phase 230V service, connect only one 

phase to each Microinverter branch. Connecting multiple phases to a Microinverter 

branch circuit will damage or destroy the Microinverters.

Step 3 – Position the Enphase Engage Cable 

Electrical Installation