Warning What does this mean?
Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.
SAJ Inverter Code 29 — L2 DCI Error Explained and What to Do
Code 29 on a SAJ inverter is an L2-phase DCI error: the inverter detected too much DC current leaking into its AC output on phase 2, and stopped feeding the grid. DCI (DC injection) is tightly limited because DC on the AC network can saturate transformers and disturb grid protection. Note the code and restart once — if 29 is constantly present, SAJ's own manual says to contact your distributor or SAJ technical support.
What should I do first?
Two quick questions — we'll point you to the right starting point.
Is this code still showing on your inverter's display?
Is your system producing power right now?
What this code means
DCI stands for DC injection — a small DC component riding on top of the AC the inverter exports. In a perfect world the inverter's output would be pure alternating current, but real electronics always produce a trace of DC offset. Grid codes strictly limit how much DC an inverter may inject (typically a fraction of a percent of rated current), because DC on the AC network can saturate distribution transformers, corrode earthed metalwork, and confuse protection devices elsewhere on the network.
SAJ monitors this continuously, and on three-phase models it watches each phase separately: codes 28, 29, and 30 correspond to DCI errors on phases L1, L2, and L3. So code 29 specifically means the phase-2 measurement crossed the limit. (On single-phase SAJ models the same fault appears simply as code 28, "DCI Error.") When it trips, the inverter stops feeding the grid — that is the safe, standards-compliant response, not a malfunction of the protection.
A one-off DCI trip is often transient. Grid disturbances, switching events on the network, or a momentary imbalance can push the DC offset past the threshold for a fraction of a second, and the inverter will usually resume normal operation on its next attempt. What matters is the pattern: an occasional 29 that clears itself is a grid hiccup; a 29 that is always present indicates something persistent — a genuine output-stage issue, a wiring or grounding problem on the AC side, or drift in the inverter's own current sensing.
SAJ's troubleshooting guidance for the DCI error is notably brief, which itself is informative: "If this error always exists, contact your distributor or call SAJ technical support." There is no homeowner adjustment for DCI — no setting to tweak, no cable to reseat — because the measurement and the limits are internal to the inverter's certified design.
What is this downtime costing you?
Rough estimate while your system isn't producing. Adjust the numbers to match your setup.
≈ – kWh of lost production per day.
Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.
Common causes
- A transient grid disturbance or switching event pushing the DC offset past the limit for a moment — the most common cause of an occasional code 29.
- Imbalance, distortion, or a local network event affecting phase L2 specifically.
- Drift or a fault in the inverter's own AC current sensing, making a normal output look like excessive DCI.
- A wiring or grounding issue on the AC side altering how the output current is measured.
- A genuine internal fault in the inverter's output stage producing real DC offset.
Safe steps to try
Work top to bottom, ticking off each step as you complete it. 0 of 5 done.
Is your inverter still under warranty?
Before paying for a repair, check — your installer may fix this free.
Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.
When to call an electrician
Call your installer or distributor if code 29 persists after a restart. Persistent DCI errors need professional measurement of the inverter's AC output and may become a warranty case with SAJ — there is no homeowner-side fix, and repeated blind restarts only extend your downtime. If the error appeared suddenly alongside other electrical anomalies in the house (flickering lights, tripping breakers), mention that to the technician, as it points toward a grid-side cause.
Frequently asked questions
What does DCI actually mean?
DC injection — direct current leaking into the alternating current your inverter exports. Grid codes cap it at a tiny fraction of rated output because DC on the AC network can saturate transformers and disturb protection equipment.
Is code 29 dangerous?
The code itself is a protection message, and the inverter responded safely by stopping grid feed-in. It is not an emergency — but a code 29 that never clears needs professional diagnosis rather than repeated restarts.
Why phase L2 specifically?
On three-phase SAJ inverters, DCI is monitored per phase: 28 is L1, 29 is L2, 30 is L3. Code 29 means the phase-2 measurement crossed the limit. On single-phase models the same fault shows as code 28.
Will code 29 clear by itself?
Transient trips often do — the inverter retries and resumes when the disturbance passes. If it is still there after a full restart (AC and DC off, five-minute wait), treat it as persistent and contact your distributor.
Need a professional?
This fault may need professional diagnosis. Contact a qualified solar electrician in your area.
Sources: meaning and troubleshooting verified against the manufacturer's documentation — SAJ R5 Series Solar Inverter User Manual (saj-electric.com) — Chapter 7 Fault Code and Troubleshooting: codes 28/29/30 listed as 'L1/L2/L3 DCI Error'; DCI Error troubleshooting: 'If this error always exists, contact your distributor or call SAJ technical support.' Also listed as '29 Phase2 DCI Error' in the SAJ CH2 Series User Manual error table (de.saj-electric.com).