Hi all

I'd like to add another string of panels, and potentially another inverter at a later stage.

With that, do I have to re-do the entire registration process on the following Scenarios:

1. Keep existing inverter, but add additional panels to current strings (system can take it)

2. Add inverter and run additional strings on this.

In scenario 2, I understand a CoC would have to be re-done and the wiring between the Main DB and Inverter DB would need to be re-done to larger cable, currently 6mm2.

And then lastly, would I have to redo the registration if I add an additional battery but system remains the same as it is currently?

I live in COJ. The technical regulations for the two cities are the same. They derive from the same national regulations.

My system is registered. I was told that if I changed inverter or panels I would have to re-register because the efficiency of the system will have changed.

Even like-for-like changes may require registration. My registration letter from the City is for an inverter with a specific serial number at specific GPS co-ordinates.

8 hours ago, Bl4d3 said:

1. Keep existing inverter, but add additional panels to current strings (system can take it)

2. Add inverter and run additional strings on this.

The registration letter from CoCT I have gives approval for a size (5kVA) and type (hybrid) of inverter. Can't see why you can't add batteries and panels to your heart's desire.

1 hour ago, frivan said:

Can't see why you can't add batteries and panels to your heart's desire.

Agree, if there is nothing on the letter there is nothing they can compare it to and nothing they can complain about! Stuff eksdom, the less they know the better.

COCT only cares about changes that affect the grid-facing characteristics of the system (AC side). Pure DC-side changes do not affect the grid and therefore usually don’t trigger re-registration or a new COC.

Scenario 1: Add more panels to the existing inverter (within inverter limits)
No re-registration required
No amended COC required
Why:
Panels are on the DC side. Inverter model, rating, and export capability remain unchanged
Anti-islanding and grid protection are unchanged
Important conditions:
Must remain within inverter:
Max PV power
Max Voc (cold conditions!)
MPPT current limits
No AC wiring or protection changes
This is why COCT does not require an amended COC for DC-side-only upgrades the COC covers the electrical installation, not panel count.

Scenario 2: Add a second inverter with additional strings:
Re-registration required
New or supplementary COC required
Why:
Inverter capacity changes
AC wiring and protection change
Grid connection characteristics change
You’ll need: Updated SSEG application
Updated Single Line Diagram (SLD)
Export limit confirmation
Cable upgrade if existing wiring (e.g. 6 mm²) is no longer adequate
This is a material system change and must be declared.

Bottom line:

If the AC side and inverter configuration stay the same, COCT doesn’t care.

Once you change inverter count, AC wiring, or export capability, paperwork is required.

This is why DC-side upgrades do not need an amended COC, even though many people assume they do.