UFC 3 -520-01
June 10, 2002
MIL -HDBK-1012/3, Telecommunications Premises Distribution Planning, Design,
and Estimating provides detailed guidance regarding telecommunications
USACE Technical Instruction 800-01, Design Criteria provides guidance
regarding facility planning and design.
Unified Facilities Guide Specifications (UFGS). UFGS are a joint effort of
the USACE, NAVFAC, and AFCESA. UFGS are intended for use in specifying
construction services or activities for the military services.
ELECTRICAL LOAD CRITERIA.
During the preliminary design stage, evaluate expected facility loading in
accordance with MIL -HDBK-1004/1. This document provides suggested demand and
load factors for analysis purposes. Include system losses in the overall estimated load
requirements; use 6 percent of the maximum load demand as a first approximation of
Evaluate the load growth design allowance based on the type of facility and
its expected mission over time. Include a minimum of 10 percent to 20 percent
allowance for load growth unless it is certain that no future expansion is planned. This
allowance provides some margin for unexpected changes during the design process
and results in a more robust electrical system.
As part of the electrical system design process, evaluate the local commercial
system reliability. If the data is available, review a 5 -year history of service outages,
including the date, time, location, duration, and cause of each outage. The commercial
system reliability will influence facili ty electrical design decisions.
Continue to evaluate the electrical loading throughout the detailed design
phase. Verify that the preliminary design load estimates continue to be acceptable or
modify the design accordingly.
In accordance wi th NEC Article 220.35 (2002 Edition) , the calculation of a
feeder or service load for existing installations can use actual maximum demand to
determine the existing load under the following conditions:
2-2.5.1 The maximum demand data is available for a 1 -year period. If the maximum
demand data for a 1 -year period is not available, the calculated load can be based on
the maximum demand (measure of average power demand over a 15-minute period)
continuously recorded over a minimum 30 -day period using a recording ammeter or
power meter connected to the highest loaded phase of the feeder or service, based on
the initial loading at the start of recording. Ensure the recording reflects the maximum
demand of the feeder or service when the building or space is occ upied and includes by
measurement or calculation the larger of the heating or cooling equipment load, and
other loads that might be periodic in nature due to seasonal variations.