Hi, I'm writing from across the ditch. I haven't yet seen anything released to the public from the NZ WorkSafe investigation into the spectacular (and vehicle-damaging) blowout of a Tritium charging station in Christchurch Nov 2019. I'd be a bit surprised if Worksafe ever did make a public release of their findings, and I doubt Tritium would want to publish a detailed technical report on this incident... so I think any outsider will only be able to guess at the electrical component which emitted that "loud bang" and what generated a shock-wave big enough to cause the front-panel to "explode off". However it seems pretty likely to me that some variation in the power supply to this unit could cause an overcurrent situation which -- due to a design, build, or operational fault in this particular charging station -- was not handled in a failsafe manner.
Failsafe shutdown of the power flows in a fast-DC charging station is quite a technical challenge, one that is far beyond my bare-bones knowledge of power-engineering. However I was interested to read (and I think the readers of this thread may also be interested to read) a press-release-cum-salespitch from Littelfuse (https://www.techbriefs.com/component/co ... cles/34153
) which briefly explains some of the issues in safety-design for fast-DC charging
"All electrical systems, including DC chargers, will eventually experience some level of overcurrent. Unless removed in time, even moderate over-currents can quickly overheat system components, damaging insulation, conductors, and equipment; large overcurrents can even melt conductors and vaporize insulation. Very high overcurrents produce magnetic forces capable of bending and twisting bus bars, and uncontrolled overcurrents can damage chargers, leading to fires, poisonous fumes, and explosions that can injure or kill anyone nearby."
Fortunately: that explosion merely blew out a panel, and no person was harmed.
<rant>There have been many, far more spectacular, safety-fails at petrol stations. And it's a dirty open-secret that there are many excess leukaemia deaths caused each year by the normal operations of petrol stations, see e.g. https://www.dailymail.co.uk/health/arti ... ealth.html
. But our human-perception of safety risks is heavily influenced by spectacular incidents, such as the heavily-reported spectacular crash of a jetliner (every few years) which kills a few hundred people in a single incident somewhere in the world, and the non-reporting of the non-news that each day more than 3000 more people die on our world's roadways.</rant>