[Gooserider]

Leak detectors are good, and IMHO should be done as 'kill power NOW' when triggered. I would also make them fairly independent of the rest of the system. One approach I've seen that I liked involved using a common basement type leak detector (used to detect sump pump failures, etc.)

These work by having two electrodes with a short gap between them, if dry there is no electric flow, and all is well. If the electrodes get wet, current flows between them and triggers the alarm. In this case the user modded the electrodes by lining the bottom of his case with two peices of aluminum screen seperated by a paper towel. In case of flood, the towel soaked up the water, shorted the electrodes and set off the alarm. The alarm had a piezo screamer, and he just bridged a relay across the terminals for the power shutdown which didn't keep the screamer from working so the box essentially would turn itself off and scream for help at the same time.

Simple and elegant....

Gooserider