How do I fix PV Insulation Protection (Alarm 1033) on a Solis?

Note the timing. Morning, late afternoon or rain reports are usually moisture and clear when dry. Then: Measure string to earth resistance, it should be above 20 kOhm. Re-cable the string if low.

Solis

PV ISO-PRO

PV Insulation Protection (Alarm 1033)

Low PV insulation. PV ISO-PRO 01 is negative to ground, PV ISO-PRO 02 is positive to ground.

Common causes

Morning dew or rain lowering insulationDamaged PV cable insulationN to PE connection issueOutdated firmware threshold

What to check

STEP 1

Note the timing. Morning, late afternoon or rain reports are usually moisture and clear when dry.

STEP 2

Measure string to earth resistance, it should be above 20 kOhm. Re-cable the string if low.

Escalate if

All checks pass but alarm persists in dry conditions

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