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DESIGN GUIDANCE FOR ELECTRICAL POWER SYSTEMS SERVING
Subj:
NONLINEAR HARMONIC LOADS
(C) Building Wiring Systems shall include dedicated neutral conductors for
each 120 volt outlet serving nonlinear equipment. Shared neutral
conductors shall not be used for outlets connected to different phases of
the same electrical distribution panel. Where shared neutral conductors
are used for 208/120 volt systems provide a neutral rated for 1.73 times
the ampacity of the paralleled phase conductors. Two paralleled neutral
conductors, each having the ampacity of the phase conductors may be
required. Where double-sized neutrals are not feasible or practical
consider a neutral overcurrent sensor to trip an upstream circuit breaker
without Interrupting the neutral conductor.
(d) Construction Cost. The above policy will Increase the construction
cost of the typical facility by a nominal percentage. This cost increase
is justified to provide the customer a more flexible facility and will
result In a reduced life cycle maintenance cost.
4. Action: NAVFACENGCOM Engineering Field Divisions, Public Work Centers,
and Public Works Departments, shall Incorporate this criteria Into the design
of new buildings and for modifications to existing facilities, which include a
high concentration (15 to 20 X) of harmonic loads. Scopes of work for
Architect/Engineer designs must contain this criteria.
5. Point of Contact: For further information please contact
Mr. Charles Mandeville at NAVFACENGCOM Headquarters, Autovon 221-0069 or
commercial (703) 325-0069
ommander for
Distribution:
eering and Design
COMSPAWARSYSCOM
COMNAVCOMTELCOM
COMPACNAVFACENGCOM
COMLANTNAVE'ACRNGCOM
COMWESTNAVFACENGCOM
CO NORTHNAVFACENGCOM
CO SOUTHNAVFACRNGCOM
CO CHESNAVFACENGCOM
CO SODTHWESTNAVFACENGCOM
CO ENGFLDACT NORTHWEST SILVERDALE WA
CO NCEL
COPWCGREATLAKES
CO PWC NORFOLK
CO PWC SAN FRANCISCO BAY
CO PWC PEARL HARBOR
CO PWC PENSACOLA
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