On Thursday, 1 October 2026, at 11:05 a.m., the 50 kV busbar protection system at the Gösgen substation was triggered, causing the 50 kV circuit breakers to trip immediately.

The outage affected 10,335 customers and 125 transformer substations in eight municipalities: parts of Gretzenbach, Däniken, Winznau and Obergösgen, as well as Lostorf, Stüsslingen, Niedergösgen and Schönenwerd.

After 15 minutes, the substation was successfully re-energised. From 11:20 a.m., all customers were once again supplied with electricity.

The exact cause of the incident is still under investigation.