FailureMode
Energy meter installation position error
- ID
fm:energy-meter-installation-error- IRI
https://solarlattice.org/kb/fm/energy-meter-installation-error- Status
- active
- Also known as
- PV connected on grid side of meter, meter orientation incorrect, phase assignment switched between charger and meter, feed-in at night, installed the wrong way round
This fault means the energy meter or its current transformers were installed wrong. The meter may be backwards, the CTs or their leads may be reversed, or the PV feeder may be connected on the grid side instead of the load side. The usual sign in monitoring is unrealistic meter values. Grid feed-in at night is another sign. If PV is on the grid side of the meter, the energy balance shows total generation equal to direct consumption, and PV output is counted as extra load. To confirm, check that the meter's neutral is on the grid side and that the CTs face the right way. Then measure each phase current and compare it with the meter's live readings and polarities. Switch the PV inverter on and off while watching the meter. If the power flow does not change, the PV is not on the load side. A power factor well away from unity suggests the voltage references and CTs are not matched phase to phase. To fix it, reconnect the meter correctly and recommission it. On three-phase hybrid systems, also make sure the inverter grid-port phases match the corrected meter phases.
<!-- review notes
- sentence 2: support check: partial - Unrealistic values and night grid feed-in are both given as symptoms, but 'usual sign' ranking is not stated.
- sentence 6: support check: partial - u35 says PF outside ±0.9 to ±1 means check voltage ref and CTs are matched phase-to-phase; 'suggests' is close, but it frames it as a check, not a diagnosis of swapped phases here.
- sentence 7: review: partial - Reconnecting and recommissioning is supported, but the Solis phase-alignment check applies to hybrid systems in Unbalanced Mode, and the sentence generalizes it to all three-phase hybrid systems.
-->
Claims
caused_by
c1 drafted · lead
Installation error
The meter is mounted backwards, CTs or their secondary leads are reversed, or the PV feeder lands on the grid side of the meter.
review note: support check: partial - Passages support meter reversed, CTs/leads reversed, and PV on grid side as installation faults, but don't name the generic 'installation error' stressor explicitly beyond 'installed wrong way round'; mostly supported.
affects
c2 drafted · lead
Energy meter
presents_as
c3 drafted · lead
Unrealistic meter values proposed
The Energy Meter has been installed the wrong way round.
- 240154
tbl=88.r1 h=23b7c5792a07
- 240154
tbl=88 h=883cfebb83c2
- 243910
sec=h54 h=3b5e487495bd
c4 drafted · lead
Meter wiring reversed
review note: support check: partial - Passages state meter/CT/lead orientation reversed causes wrong readings, but a 'meter wiring reversed' symptom is only loosely stated (wrong way round).
c5 drafted · lead
Grid feed-in at night proposed
Possible causes include a reversed meter, reversed CTs or reversed CT secondary leads.
c6 drafted · lead
Generation equals consumption reading proposed
Happens when PV is connected on the grid side of the meter: the meter only ever sees power drawn, so PV output gets counted as load.
detected_by
c7 verified · fact
Inverter switching meter check proposed
Switch the PV inverter on or off and watch the meter's live readings. If the size or direction of the power flow does not change, PV is not on the load side.
verified by: review-workflowverified on: 2026-10-24
c8 drafted · lead
Phase current measurement
Compare the measured phase currents and polarities with the meter's web interface readings. A mismatch points to a faulty meter, CT, cable or voltage-tap installation.
review note: support check: partial - u2 says mismatches between measured currents and web interface readings/polarities indicate incorrect installation (steps 1-4, 8), but 'faulty meter, CT, cable or voltage-tap' omits CT ratio setting (step 8) and is slightly mapped.
c9 drafted · lead
Visual inspection
Check the meter orientation (neutral on the grid side), the CT orientation and the CT location. Photos of CT placement help with verification.
mitigated_by
c10 drafted · lead
Meter wiring check
Reconnect and recommission the meter.
- 240154
tbl=88.r1 h=23b7c5792a07
- 243910
sec=h54 h=3b5e487495bd
c11 drafted · lead
Phase wiring correction
After you correct the meter phase rotation, also check that the inverter grid-port phases line up with the meter phases.
review note: review: partial - The Solis passage supports correcting the meter's phase rotation and then checking that the inverter grid-port phases match, but it describes phase-rotation miswiring, not an installation position error, so the link to this failure mode is not stated.
distinguished_from
c12 drafted · lead
Meter CT ratio misconfiguration — told apart by Phase current measurement
Both faults can cause export at night. If primary and secondary CT currents do not agree with the ratio, or the ratio set in the meter is wrong, the cause is the CT ratio. If the CTs or meter are reversed, the polarity is wrong.
review note: support check: partial - u2 says current mismatches vs CT ratio indicate wrong CT ratio and orientation errors cause night feed-in, but it doesn't explicitly use polarity to discriminate or state both faults cause export at night.
Referenced by
Data