100007 on an AlphaESS inverter: Insulation_fault - PV insulation resistance low
Short answer
On an AlphaESS inverter, 100007 means: Insulation_fault - PV insulation resistance low. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 24 September 2026 · 2 sources
What it means
On the SMILE-G3
The manual says: Insulation_fault - PV insulation resistance low.
Part involved: PV array cabling.
Likely causes:
- PV cable connection unreliable or PV cable damaged (earth leakage on DC side).
On the SMILE-G3 three-phase (T4/T5/T6/T8/T10)
The manual says: Insulation_fault (three-phase).
Likely causes:
- PV cable connection unreliable or damaged.
Is it safe?
On the SMILE-G3
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: typically re-tests at next start-up; persists while fault exists.
Manual reset: Restart of the inverter by installer (power-down/power-up sequence) if it does not clear.
On the SMILE-G3 three-phase (T4/T5/T6/T8/T10)
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: re-tests at start-up.
Manual reset: Restart of the inverter by installer (power-down/power-up sequence) if it does not clear.
What you can check
On the SMILE-G3
- Read the code in the AlphaCloud app/web portal (or the LED pattern on the unit) and note it with the time. Check the inverter's AC isolator and the consumer-unit breaker for the inverter are ON. Report persistent or repeating codes to your installer - AlphaESS says 'call the service' if it does not clear. Do not touch the PV cables or DC isolator; an insulation fault means a possible earth fault on live DC wiring.
On the SMILE-G3 three-phase (T4/T5/T6/T8/T10)
- Read the code in the AlphaCloud app/web portal (or the LED pattern on the unit) and note it with the time. Check the inverter's AC isolator and the consumer-unit breaker for the inverter are ON. Report persistent or repeating codes to your installer - AlphaESS says 'call the service' if it does not clear.
What the engineer will check
On the SMILE-G3
- Insulation-resistance test of each PV string to earth; inspect connectors, roof cabling and junction boxes for water ingress or damage.
Who to ask for: MCS PV/battery installer familiar with AlphaESS.
Certification: MCS-certified solar PV installer (MIS 3002) or competent electrician (BS 7671 / Part P in England & Wales); DC work only by PV-trained installer.
On the SMILE-G3 three-phase (T4/T5/T6/T8/T10)
- Insulation resistance test of PV strings; inspect cables.
Who to ask for: MCS PV/battery installer familiar with AlphaESS.
Certification: MCS-certified solar PV installer (MIS 3002) or competent electrician (BS 7671 / Part P in England & Wales); DC work only by PV-trained installer.
What you might notice
Sources
- Installation, Operation & Maintenance Manual of SMILE-G3-S3.6/S5/B5 (V01, 14.08.2023) ↗ · V01 · page p.81 (printed) · Reviewed 24 September 2026
- Installation, Operation & Maintenance Manual of SMILE-G3-T4/T5/T6/T8/T10 (LED version, V04, 2024) ↗ · V04 · page p.124 (printed) · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026