Underground transformer explosion causes widespread power outage in Halifax

A transformer located in an underground vault on Barrington Street in downtown Halifax exploded and caught fire, igniting other materials in the vault. The explosion caused a power outage affecting more than 8,500 Nova Scotia Power customers at its peak. Smoke travelled through underground conduits and sewer pipes into nearby buildings, triggering fire alarms and prompting fire crews to evacuate people from buildings on Barrington Street. Part of the street was closed between Sackville and Prince streets. Firefighters had to wait for confirmation that the vault was de-energised and grounded before they could enter and extinguish the fire. The fire was brought under control by around 9:30pm. Power was progressively restored to customers, with the final connections completed by around 5:30am the following morning.

The fire occurred within an underground electrical vault, and smoke spread through electrical conduits and sewer pipes into surrounding buildings before the fire was contained.

1. Underground vault fires require careful de-energisation and grounding verification before fire crews can safely enter, which can extend response times.
2. Smoke from underground electrical fires can travel through conduits and sewer systems into nearby buildings, triggering false alarms and requiring evacuation planning beyond the immediate incident site.
3. Utilities should have clear protocols for rapid feeder switching to minimise the duration and scale of outages during vault fires.

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