When the lights go out over a large part of a city the size of Auckland, questions must be asked. How did this happen? Who allowed it to happen? Whose head must roll?
The certainty that these questions will be asked is the one thing that can usually ensure these things do not happen. An inquiry promised by the Minister of Energy should not be limited to how the fire occurred at the Penrose substation and why sprinklers were not installed over the cables that caught fire, or who was at fault.
Inquiries are inclined to explain how a mishap occurred and suggest a way to ensure the same thing does not happen again. They are less inclined to pinpoint blame to individuals, and invariably decide a "system" was at fault.
By that they mean a deficiency in a management procedure, and they will make a long list of specific recommendations for additional procedures. The electricity line company will undertake to carry them out to the letter, and it will. It will have fixed that problem, but not the next one.
The most reliable way to ensure essential public services do not fail is to set up a system in which everyone is accountable for the decisions they are entrusted to make. Everyone should work with those questions in the back of their mind. How did this happen? Who allowed it to happen? Whose head must roll? It may sound cruel but it works. It tends to ensure the right thing is done and "accidents" are avoided.