Solar Lattice

Fault codes › SMA › Sunny Island 4548-US / 6048-US

SMA SI-US W401

Code
W401
Shown as
Reverse power protection (generator)
Vendor severity
1
Page
214
ID
fc:sma-sunny-island-us-w401
IRI
https://solarlattice.org/kb/fc/sma-sunny-island-us-w401
Status
active
Also known as
W401, w401, SMA W401, Reverse power protection (generator)
Category
Inverters
Class warning drafted · lead
Production not stated
Clears not stated

Decoded

Reports reverse power flow; look at backup generator.

What can be behind Reverse power flow

Failure modes that present as the reported condition, and the tests that tell them apart.

Defined in

The manufacturer's own cause and corrective text is not reproduced here.

Same condition on other equipment

SMA
SMA SI-US W501, SMA SI-US W502, SMA SI-US W503, SMA SI-US W504

Claims

defined_in

c1 drafted · lead SI4548-6048-US-BE-en-21W

has_event_class

c2 drafted · lead Warning (device continues, a condition is flagged)

from the Type column

reports

c3 verified · fact Reverse power flow

verified by: review-workflowverified on: 2026-10-23

affects

c4 drafted · lead Backup generator

applies_to

c5 drafted · lead Sunny Island 4548-US / 6048-US

Data