But the latest one, cause unknown and blame unattached at this stage, is troubling because the vulnerability of parts of the system is no secret. Back in 2011, the risk of fire at substations such as Penrose was identified as possibly leading to a "high-impact failure".
Part of that substation, where yesterday's fire broke out, is having $20 million spent on upgrading it. If that part of the system had been identified as a weak point, why has the work not been done sooner?
Taxpayer and consumers' money has funded the nearly $2 billion spent on fortifying national grid operator Transpower's network through Auckland over the past seven years, and lines company Vector spends hundreds of millions of dollars more on its system. Take a look at the fixed component - Transpower and Vector's share - of ever increasing power bills and you get the picture.
The highly paid heads of these monopoly businesses are making the right noises about the priority being to get power back on before starting any blame game.
But once the electricity's back on, the public need to know where responsibility lies.
Transpower and Vector say (appropriately) they can't guarantee the power will stay on all the time. They'd have to duplicate every asset to get close to that and there's no appetite for a such a multi-billion-dollar spend-up. They say it's getting power back on quickly after a big cut that really counts.
In Auckland, they're getting plenty of practice at that.
Grant Bradley is Business Herald energy reporter.
