Enphase
ACVOOR Branch

AC Voltage High on Branch (Voltage Rise)

AC voltage on a specific branch is high — typically due to cable resistance and high export current causing voltage rise along the branch.

Common causes
Undersized AC branch cable for the number of MIsLong cable run between MIs and consumer unitHigh simultaneous export from all MIs
What to check
STEP 1
Measure voltage at the consumer unit and at the far end of the AC branch. A difference of more than 2–3 V indicates cable resistance issue
STEP 2
Check AC cable size matches design spec for the number of MIs and cable length
Escalate if
Cable is correct size and length and voltage rise is excessive — DNO grid voltage issue
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More Enphase fault codes

ACVOOR
AC Voltage Out of Range
ACFOOR
AC Frequency Out of Range
DC Res Low
DC Resistance Low (Ground Fault / GFDI)
DC Too Low
DC Input Voltage Too Low
DC Too High
DC Input Voltage Too High
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