By Dave Rongey Summary: Types of Electric Wire and Electrical Cable for Home Wiring Projects. Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.
How to Choose the Right Type of Electrical Wire for Home Wiring Projects
The NEC Code requires home electrical wire to be protected and enclosed when devices such as receptacles, fixtures and switches are being
installed.
Sometimes it is necessary to junction or splice wires.
When splicing wires, an accessible junction box is necessary to enclose
the spliced wires.
This list shows various home-electrical-wire and
displays the wire name and the typical application.
The most common type of home
electrical wire that is installed for general purpose electrical circuits
is Type NM or Non-Metallic sheathed cable made
up of at least one pair of insulated wire conductors and one bare
wire used for the ground conductor. The ground conductor is bonded
throughout the home to maintain a contiguous grounded system which
originates back at the Main Service Panel.
The installation of the Type NM home electrical wire is accomplished
by drilling holes using approved methods which protects the wire and
maintains structural integrity for the home. Methods are available
to protect wiring which becomes vulnerable to damage which could occur
during the installation of sheet rock or other wall coverings. This
protection is provided by Safety Plates, as shown in the table below.
Wire Ampacity
The insulated wiring conductors inside Type NM Cable are rated for temperature.
This rating limits the current flow in amperage thereby preventing the home-electrical-wire from overheating and causing a fire.
Using the properly sized wire will ensure safe circuit performance.
Unless otherwise specifically permitted in the electrical code, the overcurrent protection for conductor types should not exceed the following:
Copper Conductors:
15 amps for #14 AWG, 20 amps for #12 AWG and 30 amps for #10 AWG
Aluminum and Copper Clad Conductors:
15 amps for #12 AWG and 25 amps for #10 AWG
These specifications are determined after any correction factors for ambient temperature and number of conductors have been applied.
Specific conductor insulation types are determined based on installation environmental factors such as free-air, dry or damp locations.
Although the preceding table is true and accurate, many times the wire type is not known. There are also instances where more than one type of wire is used on a circuit. This is why it is best to use this default chart to determine the capacity of the wire sizes listed below
Calculations for Wire Load Capacity are determined by using an 80% Load Factor.
For example:
The actual load capacity for a 20 amp #12 copper conductor would be 16 amps.
Determined by using this formula:
Amperage X .80 = Load Capacity or
( 20 X .80 = 16 )
This table shows the Amperage Rating for Home Electrical Wire Sizes
Although this is the most common table used to determine wire size, this is just one example.
Allowable Ampacity of Insulated Wire Conductors
Based on NEC Table 310-16
60 Deg C
(140 Deg F)
75 Deg C
(167 Deg F)
90 Deg C
(194 Deg F)
60 Deg C
(140 Deg F)
75 Deg C
(167 Deg F)
90 Deg C
(194 Deg F)
Wire
Types
TW,
UF
RHW, THHW, THW, THWN, XHHW
THHN,
THWN-2,
XHHW
TW,UF
RHW, THHW, THW, THWN, XHHW
THHN, THWN-2, XHHW
Wire Size
AWG
Copper Wire
Amperage Ratings
Aluminum Wire
Amperage Ratings
#14
20
20
25
-
-
-
#12
25
25
30
20
20
25
#10
30
35
40
25
30
35
#8
40
50
55
30
40
45
#6
55
65
75
40
50
60
#4
70
85
95
55
65
75
#3
85
100
110
65
75
85
#2
95
115
130
75
90
100
#1
110
130
150
85
100
115
Type-NM Cable Used for House Wiring
Copper Wire Conductors
WIRE SIZE
AWG
AMPERAGE
RATING
#14 AWG
15 Amps
#12 AWG
20 Amps
#10 AWG
30 Amps
#8 AWG
40 Amps
Common Electrical Wire for Home Circuit Wiring
Type NM Cable
Trade Name & Amps
Electrical Circuit
Wire for Outlets and Lighting
Wire for Lighting - 3-Way Switches and Smoke Detectors
Wire for Outlet Receptacles
3-Wire Circuits - Kitchen / Garage Wire
Wire for Water Heaters - Small A/C
Wire for Dryer with 4-Wire Receptacle
Wire for Small Ovens
Common Wiring Fasteners and Components and What They are Used For
WIRE PROTECTION
PART DESCRIPTION
WIRING PURPOSE and USE
Cable Staple Fasten cables to wood structure every 4-1/2' and within 8 " of boxes.
7/16 - #14 Type NM Cable 9/16 - #12 & #10 Type NM Cable 1 - Inch for Larger Cables
Perfect for Homeowners, Students, Handyman, Handywomen, and Electricians Includes: Wiring GFCI Outlets Wiring Home Electric Circuits 120 Volt and 240 Volt Outlet Circuits Wiring Light Switches Wiring 3-Wire and 4-Wire Electric Range Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet How to Troubleshoot and Repair Electrical Wiring Wiring Methods for Upgrading Electrical Wiring NEC Codes for Home Electrical Wiring ....and much more.
The Safest Way to Test Electrical Devices and Identify Electric Wires!
The Non-Contact Electrical Tester
This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.
The Quickest Way to Check for Faulty Electrical Wiring!
The Plug-In Outlet Tester
This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets
Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency
Lights indicate if wiring is correct and indicator light chart is included
Tests standard 3-wire outlets
UL Listed
Light indicates if wiring is incorrect
Very handy and easy to use.
Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!
The Wire Stripper and Wire Cutter
My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets..
The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.
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How to Wire a 220 Volt Electric Furnace How Do I Wire an Electric Furnace? Wiring Connections for 220 Volt Electric Heater and How to Connect the Electrical Circuit Wiring for a Furnace.
What To Do With The Ground Wire Grounding Wall Outlets and Light Switches: What to do When there is Nothing to Attach the Ground Wire to, Grounding Wall Outlets and Light Switches, Ground Wires and Ungrounded Fixtures and Boxes, Bonding the Ground Wire.
electrical wire - 1666
Check Out What Others Are Sharing at Ask the Electrician: Interactive, simple to navigate, & professional. Uis from Houston, Texas
Electrical Project Skill Level:
Intermediate to Advanced - Best performed by a Licensed Electrical Contractor.
Electrical Tools Required:
Basic Electricians Pouch Hand Tools and a Voltage Tester.
Estimated Time:
Depends on personal level experience, ability to work with tools, install electrical circuit wiring, and the available access to the project area. Electrical Safety:
Identify the panel circuits found in the project area, turn them OFF and Tag them with a Note before working with the electrical wiring.
Electrical Wiring Parts and Materials:
Electrical parts and materials for home wiring projects should be approved for the specific project and compliant with local and national electrical codes.
Electrical Codes and Inspections:
Installing additional home electrical wiring should be done according to local and national electrical codes with a permit and be inspected.
This is a testing tool that is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.
This is great to troubleshoot a problem with outlet circuit wiring, is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets
Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency
Lights indicate if wiring is correct and indicator light chart is included
Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect, Very handy and easy to use.
A wire stripping tool used to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets.
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