Diseño de Sistemas Eléctricos I:
Residencial y Comercial
Dr. Lionel R. Orama Exclusa, PE
enero de 2006
Introducción al Diseño
I.
¿Qué es diseño?
A.
B.
Trabajo en equipo (arq., inci, inme, inel)
Interesante, pero con complicaciones
1.
2.
3.
C.
D.
E.
F.
18-Jan-2006
el papel aguanta todo
el campo no
la sociedad tampoco
Limitaciones (“constraints”) que cumplir
Certificado por Ingeniero Licenciado
Existen Códigos y Reglamentos
Ética
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Puerto Rico’s Laws
• Electrical Design must be certified by a
licensed engineer
• Graduate from a Credited University
• Board Exams (“reválida”) must be approved
•Fundamental, Professional
• Active Member of CIAPR
•Two years of supervised engineering
experience
• The design must comply with:
• National Electrical Code (NEC)
• “Reglamento Complementario al Código
Eléctrico Nacional (AEE)”
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Proceso de Diseño
II. Proceso
A.
Propuestas de diseño, arq. Solicita costos de
electricidad para el proyecto
En general, INEL último en comenzar y terminar
una vez se aprueba la propuesta
La AEE tiene que Endosar el proyecto
B.
C.
1.
2.
Si la carga computada >50kVA (200A)
Pasos para solicitar endoso
a.
b.
c.
Estudio de campo; líneas y voltaje disponibles
Proyectos grandes, estudio de corto circuito
Punto de conexión, donde se conectaran las líneas del
edificio con las de la AEE
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Electrical Design for Buildings
• Electrical systems do not exist on a vacuum
– They are part of a product, a sub-system of an
equipment or an structure
• In this course we will confine ourselves to
design of electrical systems for buildings
– Residential - small and large dwellings units, multiple
dwellings (apartments)
– Commercial – general purpose units, offices, dining
– Industrial – basic, light industrial facilities
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El diseño en sí
A.
Computo de cargas
1.
2.
Tablas para estimados (RS Means-Electrical Cost Data,
otros), para propuesta
Por diseño, utilizando como guía el NEC
B. Circuitos ramales de iluminación
C. Circuitos ramales de receptáculos
D. Circuitos ramales para cargas de potencia
1.
2.
3.
E.
F.
Acondicionadores de aire
Elevadores y escaleras automáticas
Otros, equipos de cocina, etc.
Alimentadores y paneles de distribución
Subestación y bases de contadores
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National Electrical Code (NEC)
• National Fire Protection Association (NFPA) &
the American National Standards Institute
(ANSI) regards the Code as purely advisory
• States make it mandatory i.e. it becomes Law
with the exceptions, provisions, clarifications
that the State decides to adopt, hence the
“Reglamento Complementario al Código
Eléctrico Nacional” in Puerto Rico
• Can be difficult to read and understand
– Reading the NEC from beginning to end is worst
than reading a dictionary from beginning to end
20-Jan-2006
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NEC Article 90 - Introduction
90-1 Purpose
a) Practical Safeguarding. The purpose of the
code is the practical safeguarding of persons
and property from hazards arising from the
use of electricity
b) Adequacy – compliance (with the Code) and
proper maintenance will result in an
installation free from hazard but not
necessarily efficient, convenient or adequate
for good service or future expansion of
electrical use.
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National Electrical Code
Article 90 - Introduction
90-1 Purpose
c) Intention. This Code is not intended as a
design specification nor an instruction
manual for untrained persons.
90-2 Scope
a) Covered
1. Installation of electric conductors and equipment
within or on public and private buildings or other
structures (mobile homes, recreational vehicles,
floating bldg, yards, carnivals, parking, other lots,
and industrial substations.
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National Electrical Code
Article 90 - Introduction
90-2 Scope
b) Not Covered
1. Installations in ships, watercrafts other than
floating bldg, railway rolling stock, aircraft, or
automobile vehicles other than mobile homes and
recreational vehicles.
2. Installations underground in mines
3. Installations of railways for generation,
transformation, transmission, or distribution to
operate rolling stock, signaling and
communications
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National Electrical Code
Article 90 - Introduction
90-2 Scope
b) Not Covered
4. Installations of communication equipment under
the exclusive control of communication utilities
located outdoors or in building spaces
exclusively for such installations.
5. Installations under the exclusive control of
electric utilities for the purpose of
communications, metering, generation, control,
transformation, transmission or distribution of
electric energy.
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National Electrical Code
Article 90 - Introduction
90-3 Code Arrangement
Introduction and nine chapters
Ch. 1-4 apply generally
Ch. 5-7 special occupancies, special equipment or
other special conditions. Ch. 1-4 apply except as
amended by Ch. 5-7 for the particular conditions.
Ch. 8 covers communications systems and it is
independent of the other chapters except where
they are specifically referenced therein.
Ch. 9 are Tables
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National Electrical Code
Article 90 - Introduction
90-8 Wiring Planning
a) Future Expansion and Convenience.
• Future expansion via ample space in raceways
• Convenience via readily accessible distribution
centers
b) Number of Circuits in Enclosures.
• The number of wires and circuits confined in a
single enclosure will be varyingly restricted.
• Limiting the number of circuits in a single
enclosure will minimize the effects from a short
circuit or ground fault in one circuit.
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Reglamento Complementario al
Código Eléctrico Nacional (AEE)
•
•
Published by the Puerto Rico Electric Power Authority
(PREPA) – the authority having jurisdiction
Defines electrical constructions in three types
1. Tipo 1 – instalaciones eléctricas interiores y exteriores
2. Tipo 2 – distribución eléctrica – urbanizaciones o lotes
3. Tipo 3 – extensiones de líneas eléctricas – instalaciones
de líneas para llevar facilidades eléctricas desde líneas
de la AEE hasta urbanizaciones, lotes y edificios
*For every installation over 50kVA it includes substations
23-Jan-2006
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Reglamento Complementario al
Código Eléctrico Nacional
Seccion II Disposiciones Generales
Artículo A. Propósito
Establece, junto al NEC, las normas y requisitos mínimos
necesarios para garantizar la seguridad de personas y
estructuras en la instalación de conductores y equipo
eléctrico en Puerto Rico.
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ANSI Std Y32.9 – 1972 (1989)
The standard provides a basis for
1) Showing the general physical location and
arrangement of the sections of the required
wiring system
2) Identifying the physical requirements for
various types of materials needed to provide
the electrical installation in buildings
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Drafting Graphic Symbols
• Electrical layouts shall be drawn:
– to an appropriate scale or figure dimensions noted
– on drawing sheets separate from the architectural
or structural drawings or the drawing sheets for
mechanical or other facilities.
– Clearly. DO NOT lay out on the same drawing
sheet all different electrical systems to be installed
in the same building area. Use separate drawing
sheets for different systems such as signal system
outlets and circuits vs. lighting and power branch
circuit wiring.
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Drafting Graphic Symbols
• Outlet and equipment locations with respect to
the building should be shown as accurately as
possible on the electrical drawing sheets to
reduce reference to architectural drawings.
• All branch circuits, control circuits, and signal
system circuits shall be laid out in complete
detail on the electrical drawings, including
identification of the number, size, and type of
all conductors.
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Drafting Graphic Symbols
Complete drawings of the design shall have:
• Floor plan layout, to scale, of all outlet and
equipment locations and wiring runs
• A complete schedule of all of the symbols used with
appropriate description of the requirements
• Riser diagram showing the physical relationship of
the service, feeder and major power runs, unit
substations, isolated power transformers,
switchboards, panel boards, pull boxes, terminal
cabinets, and other systems and equipment.
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Drafting Graphic Symbols
4) Where necessary for clearness. a single line diagram showing the
electrical relationship of the component items and sections of the
wiring system.
5) Where necessary to provide adequate information, elevations,
sections and details of equipment and special installations, and
details of special lighting fixtures and devices
6) Sections of the building or elevation of the structure showing floorto-floor, outlet, and equipment heights, relation to the established
grade, general type of building construction, etc. Where
practicable, suspended ceiling heights indicated by figure
dimensions on either the electrical floor plan layout drawings or
on the electrical building section or elevation drawings
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Drafting Graphic Symbols
7) Where necessary to provide adequate information,
plot plan to scale, showing the relation of the building
or structure to other buildings or structures, service
poles, service manholes, exterior area lighting, exterior
wiring runs, etc
8) In the case of exterior wiring systems for street and
highway lighting, area drawings showing the complete
system
9) Any changes to the electrical layout should be clearly
indicated on the drawings, when such changes are
made after the original drawings have been
completed, and should be identified on the drawing by
a revision symbol
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Examples of Electrical Symbols on an
Architectural Plan
Outlet (“salida”)– a point on a
wiring system where current
is taken to supply utilization
equipment
• receptacle outlet – an
outlet where one or more
receptacles are installed
receptacle outlets symbols
single
duplex
IG
WP
Insulated Ground
Water Proof
Ground Fault Circuit
Interrupter
triplex
GFCI
F
Fan
C
Clock
Floor Outlet
Floor Single
Floor Duplex
Single
Floor Special
Purpose
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R
D
Range
Clothes Dryer
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Examples of Electrical Symbols on an
Architecturallighting
Planoutlets symbols
lighting outlet – an outlet
intended for the direct
connection of a lampholder,
lightning fixture, or a
pendant cord terminating in
a lampholder.
incandescent
incandescent
wall
surface fluorescent
X
RX
J
surface or
pendant exit
X
recessed exit
RX
junction box
J
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surface fluorescent
wall
surface or
pendant exit (wall)
recessed exit (wall)
junction box wall
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Examples of Electrical Symbols on an
Architectural Plan
Switch symbols
S
single-pole
S2
double-pole
S3
three-way
S4
four-way
SD
door
SDS
dimmer
SK
key
SWP
water proof
Circuiting symbols
cable or raceway
contains two wires
three wires on
cable or raceway
wiring concealed in
ceiling or wall
wiring concealed in
floor
wiring exposed
CO
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Examples of Electrical Symbols on an
Architectural Plan
push button
lighting panel
buzzer
power panel
bell
heating panel
telephone
(private system)
T
transformer
TV
television outlet
telephone
(outside line)
T
thermostat
M
motor
circuit breaker
overcurrent protection
device
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System voltages
There may be several system voltages available to
supply a given load but not all service voltages are
available for any load.
• 3Ø service may not be available for residential loads
• For 3Ø service a minimum load may be required
• Minimum service voltage may be specified for large loads
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RC Secc IV. Artículo N: Clases de
servicio
1. Monofásico, 120/240 V, 3 hilos. Es el servicio más común para
cargas monofásicas.
120 V
240 V
120 V
Voltaje primario de distribución - Al presente la AEE tiene 4 voltajes
de distribución: 4.16, 7.2, 8.32 y 13.2 kV. Las subestaciones de
distribución se conectan al sistema de transmisión a través de 38 ó
115 kV y sus capacidades varían desde 3.0 MVA hasta 50.0 MVA.
Toda subestación nueva se construye a 13.2 kV y su capacidad será
de 22.4 MVA si se conecta a voltaje 38 kV (estrella-estrella). Si la
subestación se conecta a 115 kV su capacidad podría ser de 33.6 ó
44.8 MVA (delta-estrella), según las proyecciones de carga.
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120 V
240 V
120 V
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a
c
b
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1Ø transf. connections
(a) and (b) show two
secondary coils
rated at 120 V
connected in
parallel to supply a
two-wire 120 V
circuit. No longer
used.
(c) and (d) show two
secondary coils
rated at 120 V
connected in series
to supply a threewire 120/240 V
circuit.
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RC Secc IV. Artículo N: Clases de servicio
2. Trifásico, 208Y/120 V, 4 hilos. Común para cargas trifásicas
pequeñas.
120 V
208 V
208 V
120 V
208 V
primario en ∆
120 V
Sirve cargas trifásicas a 208 y cargas monofásicas a 208 y 120 V
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3Ø transformer connections – ∆Y four wire grounded secondary
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RC Secc IV. Artículo N: Clases de servicio
3. Trifásico, 480Y/277 V, 4 hilos. Común para cargas trifásicas
mayores.
277 V
480 V
480 V
277 V
480 V
primario en ∆
277 V
Sirve cargas trifásicas a 480 y cargas monofásicas a 277 y 480 V
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Otros (NO en RC)
Trifásico, 240 V (ó 480) V, 3 hilos.
A
240 V (ó 480 V)
B
C
240 V (ó 480 V)
primario en ∆
Sirve cargas trifásicas a 240 V (ó 480 V) entre las fases A, B y C
Sirve cargas monofásicas a 240 V (ó 480 V) entre dos fases
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RC Secc IV. Artículo B: Asuntos Generales
• Se requiere subestación (1Ø ó 3Ø) para cualquier tipo de
edificio con carga calculada mayor de 50 kVA.
• Cualquier edificion con carga estimada que no exceda 75
kVA 1Ø ó 150 kVA 3Ø puede servirse de un transformador
o banco de transformadores instalado en poste de
hormigón de 40 pies mínimo (o entre dos postes de
hormigón de 40 pies mínimo o estructura de metal
certificada para servir graveros, hormigoneras y edificios en
construcción).
• En areas con problemas de espacio se permitirá, con
permiso de la AEE, subestaciones 1Ø de 75 kVA en postes
de la AEE si la subestación sirve más de un cliente.
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References
1. NFPA 70, National Electrical Code, NFPA, 2005.
2. Reglamento Complementario al Código Eléctrico Nacional,
AEE, 2000.
3. ANSI Std Y32.9 – 1972 (1989) American National Standard
Graphic Symbols for Electrical Wiring and Layout Diagrams
Used in Architecture and Building Construction. American
National Standard Institute.
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