We all have to go, but this is bizarre, poor fellow

[Rod Speed]

But they don't all shut at the same time and it makes more sense to have them available during the day as well.

[Fredxx]

Whereas you work and provide such a glowing example of a worker?

[Davey]

Indeed. Much industrial equipment involves safety devices being inactive when the equipment is first commissioned, as all such safety devices need to be set up from scratch. The trick is to do it all in a safe and controlled sequence. That was my working life. But you cannot account for the unexpected interference, such as the night-time painters who masked off and painted over a breather hole, but left the masking in place, and when we next pumped water in and out of the 70,000 gallon tank, it collapsed like a giant beer can. Cue agitated out-of-breath Mexican (we were at 7,000 feet ABSL): "!El tanque grande es ...!" and motion of hands squeezing a ball. Oops. A wonderful thing, industrial insurance.

[Sam Plusnet]

I worked on cabinets which had 5 separate interlocks, each designed to cut power off if you opened it up. Of course, each of those interlocks had to be tested, separately, and that involved defeating all the other interlocks and then opening the cabinet.

Dangerous business, these safety checks.

[SteveW]

For me, depending upon the customer (sometimes even the same customer for different contracts), some wanted locked panels with no door interlocks and with isolators inside, some wanted door interlocked isolators with defeaters and some wanted them without defeaters - the latter obviously requiring stopping the equipment and then restarting it with the doors already open and the isolator turned on with pliers, before testing and diagnosis could begin.

Control system interlocks often had to be overridden during testing, although we could always ensure a safe state before overriding one - such as a vessel being unpressurised and open to atmosphere or a radiation source not being present begind a gamma gate and the system to bring one in being locked off.