UFC 3 -520-01
June 10, 2002
Refer to MIL -HDBK-1004/5, 400-Hertz Medium Voltage Conversion/
Distribution and Low Voltage Utilization Systems, for further information regarding the
design of 400-Hertz power systems.
Provide all facilities with a revenue -metering installation ahead of the main
disconnecting device at the service entrance. This requirement applies to military
residential housing also. Submetering provisions should also be provided for multiple
tenants in a facility or for monitoring energy usage throughout a large facility.
Use watthour meters conforming to ANSI C12.1, Code for Electricity
Metering. In general, electronic meters are preferred.
If electromechanical meters are used, apply ANSI C12.10, Electromechanical
Watthour Meters , except that the numbered terminal wiring sequence and case size can
be the manufacturer's standard. Watthour meters can be the drawout switchboard type
or the socket-mounted type, depending on which type is most appropriate for the
application. Watthour meters should have a 15-minute, cumulative form, demand
register meeting ANSI C12.4, Mechanical Demand Registers, and should be provided
with not less than two and one -half stators. Watthour demand meters should have
factory-installed electronic pulse initiators meeting ANSI C12.1. Pulse initiators should
be solid-state devices incorporating light-emitting diodes, phototransistors, and power
transistors. Initiators must be totally contained within watthour demand meter
enclosures, must be capable of operating up to speeds of 500 pulses per minute with no
false pulses, and must require no field adjustments. Initiators should be calibrated for a
pulse rate output of 1 pulse per one -fourth disc revolution of the associated meter and
must be compatible with the indicated equipment.
Where required, install submetering provisions for energy-consuming
mechanical/electrical systems such as lighting, large motor, or HVAC systems.
Do not use meters as the principal metho d of service disconnect. Paragraph
5-1 provides the disconnect requirements for service connections.
POWER FACTOR CORRECTION . Power factor correction is not routinely
applied to interior electrical systems. Refer to Appendix C for guidance if power factor
correction is necessary.