Operating handle on disconnect switch failed to properly operate
Incident Investigation
Operating handle on disconnect switch failed to properly operate
March 2, 2019
Electrical
Reference Number:
II-821568-2019 (#*11265)
The switch was rendered inoperable and needed to be replaced.
When operating a 480Volt, 600Amp rated fused switch for a ski lift during testing, a cam mechanically connected to the operating handle broke. The switch was no longer usable to energize or de-energize the system.
A main switch, integral to an approved set of switchgear, was designed to energize and de-energize all branch circuits and bussing within the switchgear. The switch had a design lifetime of 2000 cycles. The switch was operated each morning during start-up of lift operations.