To expand my question a bit: As I understand it, the frequency of the net is very, very precisely regulated to 60.0000000 Hz over the long term, so that electric clocks will be accurate. I am unclear whether pdh was merely exercising a bit of levity, or if the actual standard is a bit off from 60 Hz, and clocks are designed to take that into account.
For comparison, the "60 Hz" field rate of NTSC television is actually slightly less than that, resulting in strange "drop frame" features in the SMPTE time code, among other things.
