in 2023 the equipment associated with our Solar install caught fire while we were away on holidays. NSW Fire Brigade and an electrician were called to assist and both confirmed the fire was a result of incorrect termination of wiring. We contacted the company that installed the system, who then sent an electrician who confirmed the issue and reported he had been asked to visit all sites setup by the same contractors.
Should we have reported this to a governing body, and if so who?
In NSW only electricity incidents associated with safety have mandatory reporting, and with these incidents there must have been some form of medical treatment:
As NSW Fire Service were involved in the incident, they would have kept records and made reports if required.
I hope the installer took responsibility for any damage caused, as they would be negligent and should have covered any damaged caused by their contractors.
Overall responsibility in NSW for regulated electrical work and the licensing of elecricians:
In New South Wales, this responsibility falls to NSW Fair Trading and the Building Commission NSW, operating under the Home Building Act 1989 and the Electricity Supply Act 1995.
As @phb commented mandatory reporting is only required for specific circumstances. To note NSW also provides for reporting (formal complaint) directly to the Building Commission NSW:
Given it is some time since the incident some uncertainty as to the priority if any the Commission might assign to a complaint. They may also consider it a resolved complaint. For future reference and the benefit of others reading this topic - there are avenues to formally notify the governing body in NSW. Since regulation varies between states and the territories those elsewhere should look for the relevant body locally. There a significant differences as to which body/s are assigned the responsibility.
In your example there was trade work done by a licensed person/s on a residential building. To the best of the knowledge of those advising the work was defective. Further a consequence of the work was that it caused damage to other structures. IE as well as the immediate electrical works? The circumstances appear to meet the criteria for making a complaint. It would also be important to include the details of how the installer responded and whether you were satisfied with the outcome. Also to note your concern as to other installs by the same contractor which as you are not able to act on or resolve.
If you choose to make a complaint (for information purposes only) feel welcome to provide an update at some time in the future. It may also prove useful to contact the Building Commission NSW more directly for advice on whether there is a better way to lodge a formal record of your experiences and concerns.