where does acceptable freq deviation come from?

[madsenate]

Where does the 0.5Hz value of "acceptable freq deviation" come from. Because on west coast, if util freq is of by more than 0.1hz, the world has come to an end.

Are communications questions really on the NETA test? These are not covered by NETA specs.

[Kalbi_Rob]

Where does the 0.5Hz value of "acceptable freq deviation" come from. Because on west coast, if util freq is of by more than 0.1hz, the world has come to an end.

Are communications questions really on the NETA test? These are not covered by NETA specs.

IEEE 446-1995 includes numerous discussions over Industrial and Commercial Practices including table 3-7 Typical range of input power quality and load parameters of a major computer manufacturer.
268
Section 3.11.3.3 discusses the various effects of frequency variations such as:
"The manufacturer’s tolerance on 60 Hz equipment ranges from ±0.5 Hz to ±1%, with the majority of the equipments limited to ±0.5 Hz. Time-related peripheral devices are most sensitive to frequency (clocks, card readers, magnetic tapes, disks). "