Understanding the "Check Grid CT / Installation Limit / Grid CT Lost" Error

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myenergi troubleshooting guide

Check Grid CT / Installation Limit / Grid CT Lost

This message appears when the system detects a problem with the Grid CT setup or readings. It is a common issue and often easy to fix with basic checks.

Important safety information

Some steps involve checking wiring or the physical installation of a CT clamp. This must only be done by a suitably qualified person. If you are unsure, speak to your installer before doing any work.

System configuration note

The device must either be set as a Master or paired to one. If it is not, this message will appear even if there are no other devices on the system.

Troubleshooting

Possible causes and solutions

Expand each section to see the possible problem, symptoms and recommended solution.

Multiple CTs set to “Grid”
Problem

Only one CT (or one set of three for three-phase) should be assigned as the Grid CT. Having more than one causes conflicting readings.

Symptom

One CT may read zero or show incorrect values.

Solution

Check all devices. Only one should show the tilde (~) symbol, which means it’s set as the Grid CT. Change any others from Grid to NONE in the menu.

Grid CT configuration example
Grid CT not fitted or activated
Problem

If the Grid CT has not been installed or activated, the system cannot measure or control power flow.

Symptom

No grid readings or power diversion.

Solution

Look for the tilde (~) symbol to confirm the CT is present. If missing, contact your installer to fit and activate the Grid CT.

Grid CT activation example
Incorrect Grid CT placement
Problem

The Grid CT must monitor all electricity flowing into and out of the property. Incorrect placement leads to false readings.

Symptom

Readings that don’t match usage or exports.

Solution

The CT should be fitted on the live cable from the electricity meter. In setups using a Henley block or split consumer unit, confirm the CT is positioned before any branch circuits.

Grid CT placement example
Grid CT installation example
Faulty or disconnected Grid CT
Problem

A damaged or unplugged CT will stop readings or show unstable data.

Symptom

Data loss or erratic readings.

Solution

Check connections are secure. Replace the CT if it’s damaged or not working correctly.

CT clamp
Improper installation
Problem

Incorrect wiring or loose fittings cause poor readings.

Symptom

Missing or inaccurate measurements.

Solution

Have the installer check that wiring follows myenergi’s CT fitting guidance.

Exceeding installation limits
Problem

The CT’s rated current limit has been exceeded.

Symptom

“Installation Limit” or overload messages.

Solution

Ensure current is within the CT rating. Fit a higher-rated CT if required.

CT installation reference
Loose or damaged connections
Problem

Loose or corroded CT wiring disrupts signal.

Symptom

Inconsistent or dropped readings.

Solution

Secure or replace any damaged wiring or terminals.

CT wiring connection example
Firmware or software issues
Problem

Outdated firmware or software can cause CT errors.

Symptom

Incorrect or inconsistent readings.

Solution

Update to the latest firmware and reboot the system.

Electrical interference
Problem

Electrical noise or nearby high-current cables can affect CT readings.

Symptom

Unstable data or fluctuating readings.

Solution

Route CT cables away from other high-power wiring or use shielding.

Environmental factors
Problem

Moisture, cold, or heat may degrade CT performance.

Symptom

Unreliable readings or gradual drift.

Solution

Protect the CT from damp or extreme temperature exposure.

Wireless CT connectivity

Impact of harvi connectivity

If your system uses a harvi and it disconnects due to range or interference, CT readings will stop temporarily and an error will display. Once the connection is restored, normal operation resumes automatically.

See Troubleshooting harvi connectivity issues for further help.

Quick checks

Steps for self-resolution

These checks can help identify some of the common causes of Grid CT errors.

  1. Ensure only one device is set as Grid CT (tilde symbol ~ visible).
  2. Check CT is installed on the live cable from the electricity meter.
  3. Confirm the Grid CT is present and connected correctly.
  4. Update all device firmware and restart if necessary.

Need help with the installation?

Any checks involving wiring, CT connections or the physical installation must only be carried out by a suitably qualified person. Contact your installer if you are unsure.

myenergi Support · Grid CT Troubleshooting Guide

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