Transcript Home Inspection Book - PowerPoint for Ch 09

The Home Inspection Book: A
Guide for Professionals
By Marcia Darvin Spada
Copyright,
Thomson/South-Western,
2003, Revised, 2006
Chapter 9
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2
Inspecting the Electrical System
Chapter 9 Inspecting the Electrical
System
Chapter 9 Key Terms
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3
Amperage
Branch circuit wiring
Bus bars
Circuit
Conductor
Electric current
Fuse
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Ground fault circuit
interrupter (GFCI)
Insulator
Junction box
Neutral bus bar
Ohm
Overcurrent protection
devices
Chapter 9 Inspecting the Electrical
System
Chapter 9 Key Terms
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Raceway
Receptacle
Service drop
Service entrance
cable
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4
Service lateral
Service lateral
conductor
Switch
Transformer
Voltage
Chapter 9 Inspecting the Electrical
System
Definitions
Electricity
Flow of electrons
Conductors
Wires
Ohm
Unit of electrical
resistance
5
Insulator
Prevents shock
Voltage
Pressure through
wires
Amperage
Amount of current
Transformer
Reduces voltage
Chapter 9 Inspecting the Electrical
System
Above Ground and Underground
Service
6
Chapter 9 Inspecting the Electrical
System
Service Lateral
7
Chapter 9 Inspecting the Electrical
System
Grounding
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8
Electrical systems must
be grounded
Connected to the earth
to limit excess voltage
from:
lightning
line surges
contact with higher
voltage lines
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Grounding ensures that
overcurrent
protection devices
respond quickly to
ground faults. Devices
include:
main disconnect
circuit breakers
fuses
Chapter 9 Inspecting the Electrical
System
Service drop system grounding
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Chapter 9 Inspecting the Electrical
System
Main Panel Board
10
Chapter 9 Inspecting the Electrical
System
Panel Board Circuit Schedule
11
Chapter 9 Inspecting the Electrical
System
Main Panel Board with Circuit Breakers
12
Chapter 9 Inspecting the Electrical
System
Commonly Used Fuses
13
Chapter 9 Inspecting the Electrical
System
Inspecting the Main Panel Board, Main
Disconnect, Fuses and Circuit
Breakers
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Inspection points:
Location of main and
subpanels
Condition-rust, corrosion,
cover, exposed wiring
Locate the grounding
conductor
If grounded to metal water
pipe, must be bonded
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14
Note amperage service
If feasible, determine if
service entrance cable is
compatible with amperage
rating
If main disconnect outside,
check if watertight
If no main disconnect,
determine if power
disconnect with no more
than 6 hand movements.
Check for proper fuse size
Chapter 9 Inspecting the Electrical
System
Wiring Materials
Copper
Aluminum
BX Cable
Wiring
Materials
Greenfield
(flexible
conduit)
Romex
Cable
Conduit
15
Chapter 9 Inspecting the Electrical
System
Inspecting the Wiring
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Inspection points:
Check that wires not
hanging loose
Identify type of branch circuit
wiring
Identify if aluminum wire
connected to 15-amp
breaker or fuses (safety
hazard)
Note any knob and tube
wiring as safety hazard
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Note number of outlets;
overloaded extension cords
Note any spliced wires in
main panel board
Check if wiring size matches
ampere rating in main panel
board
Check for evidence of burnt
wiring
Chapter 9 Inspecting the Electrical
System
Junction Boxes and Outlets
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Junction Box
Contains wiring and
used for space for
electrical connections
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Outlet
Point on wiring system
where current is taken
to supply equipment
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Receptacle
Connected to branch
circuit wires that supply
current to equipment
Switches
Open and close
electrical circuits
Chapter 9 Inspecting the Electrical
System
Junction Boxes and Outlets
18
Chapter 9 Inspecting the Electrical
System
Ground Fault
Circuit Interrupter
GFCI shuts circuit
Bathrooms
Outdoors
Kitchens
Garages
Wet bars
Workshops
Unfinished basements
Swimming pools
Crawl spaces
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Chapter 9 Inspecting the Electrical
System
Inspecting Junction Boxes, Plugs,
Switches and GFCIs
 Inspection
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points:
Check visible boxes
Use circuit analyzer to
check a number of
outlets
Determine if plugs have
adequate reading
Trip GFCI and check to
see if in appropriate
locations
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Check receptacles to
see if properly polarized
Check receptacle for
open ground
Test wall switches
Note non working light
fixtures
Check for electric
heaters
Chapter 9 Inspecting the Electrical
System