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Before reading this article please be sure to check the following guides:
One of the main symptoms of a CT issue is incorrect readings, this may present as PV mirroring the home loads, no home loads being read, export to the grid at night, and no PV production readings, amongst other symptoms.
Incorrect readings may affect the system's performance as this information is needed for the system to execute its logic accordingly
Performing the tests below may help in identifying CT issues
TABLE OF CONTENTS
- aGate 1.1
- aGate 1.3
- Testing protocol for load CT installs (either upstream or split panel)
- Testing protocol for non-backup PV installed according to Split PV CT Guide
aGate 1.1
Check the basics first!
- Confirm the CT configuration (Main Panel Consumption Metering, Sub-panel Consumption Metering, PV production metering)
- Confirm that the arrows on the CT clamps are pointing toward the load and not the power source
- Confirm CT clamps are correctly placed around L1 and L2 (check for polarity)
Main Panel and Sub-Panel Consumption Metering
Main panel not connected to the non-backup lugs
- Confirm CT3 is clamped to L1 and CT4 to L2
- Confirm The total current of the main panel must not exceed 200A
- Confirm L1 and L2 are bundled correctly with factory wires (L1 has a black tip, L2 has a red tip) see Ref 1 Below
| Ref 1 | |
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PV production metering
Split PV is connected to the sub-panel and allowed to export power to the grid
For this remote load-side connected PV, it is best practice to utilize the FranklinWH aPbox for measurement and control of the PV array. The CT’s do not offer control of this PV and without control, off-grid stability may be negatively affected.
- Confirm CT3 is clamped to L1 and CT4 to L2
- Confirm Meter 2 is being used for this purpose
- Confirm L1 and L2 are bundled correctly with factory wires (L1 has a black tip, L2 has a red tip) see Ref 1 Below
- Turn everything back on and confirm that the remote PVis producing (may take up to 5 minutes)
- Confirm if readings are correct, you may compare them to the inverter's app (if available)
aGate 1.3
Check the basics first!
- Confirm the CT configuration (Main Panel Consumption Metering, Sub-panel Consumption Metering, PV production metering)
- Confirm that the arrows on the CT clamps are pointing toward the load and not the power source
- Confirm CT clamps are correctly placed around L1 and L2 (check for polarity)
Main Panel and Sub-Panel Consumption Metering
Main panel not connected to the non-backup lugs
- Confirm CT3 is clamped to L1 and CT4 to L2
- Confirm the CTs are connected to the CT3 and CT4 ports on the EMS
- CT3 Wiring White Wire: Connect to the terminal marked CT3 +. Black Wire: Connect to the terminal marked CT3 -
- CT4 Wiring White Wire: Connect to the terminal marked CT4 +. Black Wire: Connect to the terminal marked CT4 -
- Confirm the original built-in grid CT has been removed and insulated (this could create double readings)
- Check that Utility Grid CT is enabled in the settings and Secondary solar is disabled
PV production metering
Split PV is connected to the sub-panel and allowed to export power to the grid
- Confirm CT2 is clamped to the PV leg and the arrow is pointing towards the panel
- CT2 Wiring: White Wire: Connect to the terminal marked "CT2 +". Black Wire: Connect to the terminal marked "CT2 -"
Testing protocol for load CT installs (either upstream or split panel)
- Turn Off PV Breakers:
Begin by switching off any photovoltaic (PV) breakers. - Turn Off Battery Breakers (Optional):
This step may be skipped as you become more familiar with checking direct battery performance. - Grid Feed Comparison:
- Use the Franklin app to compare the grid feed readings with the utility meter.
- If there is a valid reason for these values to differ, investigate accordingly.
- Typically, CTs (current transformers) are installed to capture all loads behind the service meter, so the numbers should align.
- Mismatch Investigation:
- If the values do not match, check the individual leg readings using FleetView or the FWH app.
- Compare these readings with on-site measurements from a clamp-on meter, confirming each leg separately.
Handling Multiple CT Sets:
- If multiple CT sets feed the meter, disconnect one set.
- Test the same location using the connected set, then repeat the process for the other set.
- This is particularly important for split-load panels where built-in CTs are still active.
CT Adjustment:
- Adjust or flip CTs as necessary until the readings align.
- Isolate L1 and L2 individually during this process unless both sides show incorrect readings.
- Focus on correcting the side with the discrepancy.
Testing protocol for non-backup PV installed according to Split PV CT Guide
Turn Off the PV Breaker:
- Locate and turn off the PV breaker in the top left section of the aGate.
Turn Off aPbox Breakers:
- Switch off any aPbox breakers.
Note: If turning off either breaker causes the PV you are monitoring to disappear, you may be working in the wrong location.
- Switch off any aPbox breakers.
Verify PV Production Readings:
- Check PV production in FleetView or the FWH app.
- If the readings do not align, use a clamp-on meter to confirm the values.
Diagnose Incorrect PV Readings:
- If the system shows the PV indicator as active but displaying 0 kW, and the grid shows back feed (depending on the load), the PV meter may be reading in reverse.
- In this case, the CTs need to be flipped.
- Flipping individual legs is typically unnecessary but may be required if the issue persists.