Installation guidance
Current Transformer (CT) Guide
Understand the CT clamps supplied with your myenergi product, how they should be installed and the important rules to follow when using additional CTs.
How many CTs are supplied?
zappi, eddi and libbi come with one wired CT clamp as standard. The 22 kW 3-phase zappi comes with three CTs as standard.
One wired CT clamp supplied as standard.
One wired CT clamp supplied as standard.
Three CT clamps supplied as standard.
Additional CT clamps: If you would like to see real-time generation from your solar or wind system displayed on your product's LCD screen, you will need an additional CT, available as an optional extra. In some cases, extra CT clamps are required, for example for 3-phase installations.
Grid CT: golden rules
The Grid CT measures electricity imported from and exported to the grid. Its position, orientation and phase are important for accurate readings.
- Only ONE Grid CT per phase. Check for only one ~ symbol in Linked Devices Info.
- Measure all import and export current. The Grid CT must be located so it can see ALL import and ALL export current. It should always be upstream of any junction box.
- Check the arrow direction. The arrow should point in the direction of import (for example, towards the consumer unit if fitted on the Live cable).
- Use the same phase as the Master device. The Grid CT must be in the same phase as the Master myenergi device.
All other CTs
Follow these rules when installing CT clamps for measurements other than the Grid CT.
CT orientation
- The arrow should point towards the consumer unit.
3-phase harvi CTs
- When using harvi in 3-phase mode, the CT inputs correspond to the phase number (for example, CT1 = Phase 1). This helps avoid phase shifting or phase misalignment.
CT dos
CT clamps offer flexibility when setting up your myenergi system. The following points explain what is supported.
- CTs can be wired to ANY myenergi device in the network.
- harvi can be used to make ANY CT wireless.
- The cable can be extended up to 100m. Twisted-pair cable must be used, for example one pair of CAT5.
- The cable can be shortened.
- A CT can be clipped around two or more conductors feeding appliances of the same type (for example, two Live cables from two inverters that are on the same phase).
- CTs can be close to other CTs.
- Wires can be swapped around in the device to reverse the direction of the readings (for example, change import to export).
- CTs can be grouped with other CTs of the same type so that the power reading is summed (for example, east and west solar generation).
- A CT can be used on the Neutral conductor. The direction of the arrow or wires must be reversed.
- A CT can be set to None if you want to exclude the reading.
CT technical information
The CT specification and cable-extension guidance are available below.
CT specification and extending CT cables
CT specification
The turns ratio of our CTs is 2500:1. This means that 100A on the primary will give an output of 40mA on the secondary.
| General Spec: 16mm Current Transformer | |
|---|---|
| Reference | CT100-16-05 |
| Window Size | 16mm |
| Weight | 100g |
| Input Current | 100A |
| Output Current | 40mA |
| Accuracy | +/- 10% |
| Output Protection | 10V |
| Frequency | 50-60Hz |
| Temperature Ratings | -40˚C to +70˚C |
| Housing | PA66 (UL 94-V0 |
| Output Wire | 5m UL1015 24 AWG, twisted pair |
| Standards | ANSI C24.13 / IEC 60044-1 |
Extending CTs
The CT comes with a 5m cable. If there is a need to extend the CT sensor cable, twisted-pair cables like CAT5 or telephone cables must be used. Only use one pair.