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Settings can be configured incorrectly without any visible error. The utility meter cannot be fooled. Run these three live tests at commissioning and repeat them after any CT, meter, or export-setting rework — they are the only reliable proof that the sensing chain and control loop are working.
For trained and authorised installers only. These tests involve switching real loads and opening real breakers. Brief the customer before starting and confirm the site is ready for brief supply interruptions.

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Before you start

  • System commissioned to the point of a live display.
  • CT or meter physically installed per Direction & Location.
  • A known heavy single-phase load identified and available — kettle, geyser, iron-class (per phase on the Kent G3).
  • Eyes on both the inverter display and the utility meter.

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Test 1 — CT Direction (convention-proof)

This test proves the CT is at the right location and pointing the right way without relying on anyone’s remembered arrow convention.
1

Set the starting condition

Grid ON. DC switch OPEN — no PV generating. Battery idle.
2

Confirm import on the display

The inverter display must show the site importing from the grid. With no PV and real loads running, import is the only correct reading.
3

Step the heavy load

Switch on the high-current load. The grid import figure on the display must rise by the load’s approximate wattage, and the sign must remain import.
4

Record and photograph

Capture the display reading with the load on. Note the import value.
Pass: import shown before and after the load step, correct sign, figure rises with the load. Fail: sign is flipped, reading is zero, or figure moves in the wrong direction. Fix physically — see Direction & Location — before continuing.

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Test 2 — Per-Phase Mapping (Kent G3 only)

Run Test 2 only after Test 1 passes. This test confirms that each CT is on the correct conductor and connected to the correct terminal pair.
1

Step a known load on L1 only

Switch on a load you are certain is single-phase on L1. Use a single-phase socket on the L1 circuit — not a multi-phase outlet.
2

Confirm only L1 responds

The L1 reading on the display rises. L2 and L3 stay flat. Photograph the display.
3

Repeat for L2

Switch the L1 load off. Step an L2 load. Only L2 rises on the display.
4

Repeat for L3

Switch the L2 load off. Step an L3 load. Only L3 rises on the display.
Pass: each phase reading responds only when that phase is loaded. Fail: the response appears on a different phase, or more than one phase moves. Fix the CT-to-conductor or lead-to-terminal mismatch — see Meter & Phase Matching.

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Test 3 — Zero-Export Witness (export-limited sites)

This test is mandatory on all export-limited sites, and specifically required on Kent M1 sites before sign-off [KNB-VAL-07]. Configure all export settings before running it.
1

Set the conditions

Pick the hardest available window: PV generating at a high level, site load minimised. This maximises the surplus the control loop must manage.
2

Watch the utility meter — not only the inverter display

Monitor the utility meter for several continuous minutes. Include the moment of a sudden load drop (switch off a load mid-test) to stress the loop’s reaction time.
3

Evaluate the export trace

Brief momentary blips on load steps are expected and acceptable — that is the loop reacting. Sustained export above the configured limit is a fail.
4

Record and photograph

Capture the utility meter during the test window. Note the maximum observed export and the duration.
Pass: no sustained export above the set limit on the utility meter; only momentary blips on load steps. Fail: sustained export — see Wrong-CT Symptoms first, then if the CT is confirmed good, Zero Export — The Concept for the settings investigation.

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Record it

Each test result needs a line in the commissioning record:
TestConditionReading / resultPhoto ref
Test 1 — DirectionGrid ON, PV OFFImport: ___ W📷
Test 2 — Per-phase (L1)L1 load steppedL1 rise: ___ W, L2/L3 flat📷
Test 2 — Per-phase (L2)L2 load steppedL2 rise: ___ W, L1/L3 flat📷
Test 2 — Per-phase (L3)L3 load steppedL3 rise: ___ W, L1/L2 flat📷
Test 3 — Zero-exportPV high, load lowMax sustained export: ___ W📷
Follow the commissioning record with a settings snapshot — a screen capture or photograph of every relevant setting as configured and witnessed.

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Common mistakes

PV output can mask the import and make the sign look correct even when it is not. The test condition is grid ON, PV OFF.
DISCOM penalties are based on the utility meter reading. Watch the utility meter for Test 3 — not the inverter screen.
A multi-phase outlet loads more than one phase simultaneously. Use a confirmed single-phase socket for each per-phase step.
CT direction correct, phases crossed is still a wiring fault — it just fails silently on a lightly loaded site.