The Home Inspection Book: A
Guide for Professionals
By Marcia Darvin Spada
Copyright,
Thomson/South-Western,
2003, Revised, 2006

2
Chapter 9
 Inspecting the Electrical System
Chapter 9 Inspecting the Electrical
System

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Chapter 9 Key Terms
 Amperage
 Branch circuit wiring
 Bus bars
 Circuit
 Conductor
 Electric current
 Fuse
 Ground fault circuit interrupter (GFCI)
 Insulator
 Junction box
 Neutral bus bar
 Ohm
 Overcurrent protection devices
Chapter 9 Inspecting the Electrical
System

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Chapter 9 Key Terms
 Raceway
 Receptacle
 Service drop
 Service entrance
 cable
 Service lateral
 Service lateral conductor
 Switch
 Transformer
 Voltage
Chapter 9 Inspecting the Electrical
System

Definitions
Electricity
Flow of electrons
Conductors
Wires
Voltage
Pressure through wires
Amperage
Amount of current
5
Ohm
Unit of electrical resistance
Insulator
Prevents shock
Transformer
Reduces voltage
Chapter 9 Inspecting the Electrical
System

6
Above Ground and Underground
Service
Chapter 9 Inspecting the Electrical
System

7
Service Lateral
Chapter 9 Inspecting the Electrical
System

Grounding
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 Electrical systems must be grounded
 Connected to the earth to limit excess voltage from:

 lightning line surges
 contact with higher voltage lines
 Grounding ensures that overcurrent protection devices respond quickly to ground faults. Devices include:
 main disconnect
 circuit breakers
 fuses
Chapter 9 Inspecting the Electrical
System

9
Service drop system grounding
Chapter 9 Inspecting the Electrical
System

10
Main Panel Board
Chapter 9 Inspecting the Electrical
System

11
Panel Board Circuit Schedule
Chapter 9 Inspecting the Electrical
System

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Main Panel Board with Circuit Breakers
Chapter 9 Inspecting the Electrical
System

13
Commonly Used Fuses
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





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

15
Wiring Materials
Copper
Aluminum
Greenfield
(flexible conduit)
Wiring
Materials
Conduit
BX Cable
Romex
Cable
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




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
 Junction Box
 Contains wiring and used for space for electrical connections
 Receptacle
 Connected to branch circuit wires that supply current to equipment
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 Outlet
 Point on wiring system where current is taken to supply equipment
 Switches
 Open and close electrical circuits
Chapter 9 Inspecting the Electrical
System

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Junction Boxes and Outlets
Chapter 9 Inspecting the Electrical
System

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Ground Fault
Circuit Interrupter
GFCI shuts circuit
Bathrooms
Outdoors
Kitchens
Garages
Wet bars
Workshops
Unfinished basements
Swimming pools
Crawl spaces
Chapter 9 Inspecting the Electrical
System

Inspecting Junction Boxes, Plugs,
Switches and GFCIs
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 Inspection 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
 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