Water Main Cut Leads to High Voltage Equipment Failure at Mall

Location: Salmon Arm

Regulated industry sector: Electrical - High voltage electrical system (greater than 1000V)

Incident overview

While cutting a concrete floor at a mall, a contractor accidentally cut a water main elbow, causing water to spray over a protective barrier and onto high voltage equipment. This wet a 25kv sub-station, triggering the utility's overcurrent protection system upstream. The sub-station's own overcurrent protection failed to operate, due to an inoperable main breaker that was previously identified through maintenance and inspection years prior but never repaired. This failure caused the utility's overcurrent devices to act as the safety mechanism, de-energizing the electrical equipment at the mall.