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INTRODUCTION TO

ELECTRICAL SYSTEM DESIGN

EEE 3 2nd Sem, AY 2011 - 2012

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What Electrical System Design

When Before, during, and after a construction project

Who Electrical Engineer, Architect, Owner, Contractor, Builders

Why Produce a working/electrical plan

- visualize the project- avoid wasting resources (materials, effort, time)- documentation and assessment of the design- coordination of whos

How Sizing and arranging electrical equipment, conductors,

devices and instruments to safely and effectively transferelectric energy from a source of power to lamps, motors, andother functional devices which operate on electricity.Then putting it on paper as a plan.

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RESPONSIBILITIES

What are the responsibilities of an electrical designer?

1) Study and establish the electrical needs of the unitand characteristics of the power supply.

2) Scale details of the overall electrical system to meet thelimitations of budgeted funds.

3) Ensure conformity to applicable codes and standards.

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Characteristics of a good electrical system design

Reliability

The electrical system provides continuity of electrical supply takinginto consideration the nature of activities within the building orfacilities.

Flexibility

The layout and type of equipment should readily accommodatechanges in the locations of electrical loads and future requirementssuch as additions, extensions or modifications to the system.

AccessibilityThe design of the system must provide ease of access to equipmentfor maintenance and repair.

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PRELIMINARY CONSIDERATIONS

1. Determine the characteristics of the building/facilities- Type of building: industrial plant, office building, school,hospital, etc.

- Small or large

- Single-storey or multilevel

2.Standardize equipment types and ratings- Standardization results in significant economy, both for theinitial capital requirements and inventory of replacement parts.

- Lack of standardization complicates maintenance, therebyreducing the efficiency of maintenance personnel.- The use of special, nonstandard equipment and voltages mayseriously impair expansion or modification of the electricalsystem at a later date.

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THE PHILIPPINE ELECTRICAL CODE

1. Purpose

- The primary objective of the code is to establish basic

material quality and electrical work standards for thesafeuse of electricity for light, heat, power, communications,signaling, and other purposes.

2. Classification of Code rulesa. Wiring design rules

b. Installation rules

c. Manufacturing rules

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BASIC ELEMENTS OF ELECTRIC DISTRIBUTION SYSTEM

Main

DistributionPanel

DistributionPanel

DistributionPanel

Lighting

Panelboard

Lighting

Panelboard

Lighting

Panelboardfeeders

sub-feeders

sub-feeders

branch circuits

branch

circuits

branch

circuits

branch

circuits

service

entrance

This diagram is a single-line diagram

used for power flow analysis

SOURCESIDE

LOADSIDE

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MainDistribution

Panel

Distribution

Panel

DistributionPanel

Lighting

Panelboard

Lighting

Panelboard

Lighting

Panelboardfeeders

sub-feeders

sub-feeders

branch

circuits

branch

circuits

branch

circuits

branch

circuits

serviceentrance

SOURCESIDE

LOADSIDE

Design Flow