Symptom: the grid fails and the essential loads go dark — or the backup trips within
seconds of every outage.
For trained/authorized installers only. Simulated-outage testing opens live breakers
with the customer’s loads attached — brief them first.
Check first
- What was on the backup at the moment of failure? Peak load history and the customer’s
account — one appliance too many is the leading cause.
- Battery state at the time — an empty or threshold-parked bank has nothing to give;
that branch is Battery Not Discharging.
- Which device tripped — inverter alarm, backup MCB, or an RCD? An RCD points to
Nuisance Tripping.
Prove the fix
Re-run the black-start test with the real essential loads: open the grid breaker, loads
ride through, clean return on restore, no RCD trip. 📷
Escalate when
- Overload trips repeat with measured load inside the platform’s ratings — hardware check.
- Any suspicion the Grid supply ever reached the Backup port.
- Transfer behaviour is erratic after the above causes are cleared.
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