We more or less had one of these.
It was third shift at Purolator Courier's data center. We'd just finished the night's batch run, we were running the backups, CICS was getting ready to come back up.
We had had some squirrelly underfloor sensors all day, because the cleaning people had been in to vacuum under the floor which always stirs up dust and sets them off. It would kick the trouble alarm rather infrequently through the overnight. We'd yawn, wake up, go over to the annunciator panel, hit "Reset" and that would be it.
A gung ho tape jockey had come in to relieve the shift supervisor, who had retired to the shift supervisor's office for a nap after a hard night of pressing the "Enter" key. GHTJ sits bolt upright at the next sounding of the alarm and goes over to the annunciator panel, opens it, and apparently not realizing it's a trouble alarm figures he'd save the night's work by hitting the Halon Dump Abort switch so that we wouldn't have to evacuate the data center - halon being not very breathable, you see. However, the annunciator cover was open and his head was in the innards, and his aim was a bit off...
Yup.
Right for the Emergency Power Cutoff.
BAM! The breakers all popped, lights went off, fans sighed to a halt here in the operations room. The one where the tape drives and consoles and printers were. We knew with a sinking feeling that the same thing was happening on the floor above us, where the CPUs and DASD (Direct Access Storage Device, "Disks" to those of you from Rio Linda) were now sighing to a halt, their circuit breakers tripped and un-resettable except by an IBM Customer Engineer.
In the deafening silence, the phone rang. It was the Indianapolis air hub, which all of a sudden had sudden blank screens as all its planes came in for sorting the night's volume of packages...
Whoops.
The next night there was a plexiglass cover over the Emergency Power Cutoff switch. The Gung Ho Tape Jockey I think went back to hanging tapes. I don't remember.