[pwg]

Does anyone know if this 'experiment' became permanent?:

Planned U.S. Power System Experiment Means Some Clocks Will Speed Up

http://spectrum.ieee.org/tech-talk/energy/the-smarter-grid/p...

Because if it did, then at least in the US, the 60Hz grid frequency is no longer a 'good' stable time-of-day clock reference.

Anecdotal evidence (my own old 60Hz line-synced alarm clock) prior to this experiment kept very good time (drift of 1-2 minutes over a year or more). Ever since this announcement, it has drifted fast such that I need to reset it about once a month for it to be reasonably accurate. And the drift now after a month or two is on the order of 5+ minutes.

[tankenmate]

If you use a tuned quartz crystal oscillator you shouldn't have any problems.