Electric Wire and Electrical Cable

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.
© By: Dave Rongey

How to Choose the Right Type of Electrical Wire for Home Wiring Projects

DIY Electrical Wiring Video

How to Wire a GFCI Outlet without a Ground Wire

<span style="display: inline-block; width: 0px; overflow: hidden; line-height: 0;" data-mce-type="bookmark" class="mce_SELRES_start">?</span>

NOTE: A List of All my Helpful Videos

Will Display at the End of This Video

So Keep Watching So I Can Help You Wire it Right!

Check out my YouTube Channel:
» AskTheElectrician «
and Subscribe!

Home Electrical Wire and Type NM Cable

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
	Safety Plate	Protect the wires in vulnerable areas How to Home Wiring Projects

Common Wire Connectors and What They are Used For
WIRENUTS and WIRE CONNECTORS	WIRE CONNECTOR	CONNECTOR CAPACITY
	Large Blue Wirenut	#14 thru #6 AWG Min. 3 #12 Max. 2 #6 w/ 1 #12
	Large Gray Wirenut	#18 to #6 AWG Min. 2 #12 Max. 6 #12
	Red Wirenut	#18 thru #8 AWG Min. 2 #18 Max. 4 #10
	Yellow Wirenut	#18 thru #10 AWG Min. 2 #18 Max. 3 #12
	Orange Wirenut	#22 to #14 AWG Min. 1 #18 w/ 1 #20 Max. 4 #16 w/ 1 #20

Common Earth Grounding Components and What They are Used For
GROUND BONDING PART	PART DESCRIPTION	GROUND PURPOSE and USE
	Crimp Sleeve	Joining two or three #14 or #12 bare ground wires to form a "tail" for bonding plugs & switches
	Green Grounding Screw	Bond the ground wire using tapped ground access #14 and #12 wires
	Grounding Clip	For older metal boxes without a ground screw access #14 and #12 wire
	Ground Lug	Bonding larger wires various sizes for wires

Remember to always check the device specifications for the Required Amperage and Circuit Breaker size, then select your home electrical wire size.

More about Electrical Wire

Recent Questions and Comments

Wiring Two Ceiling Fans and Switches

How to Wire Ceiling Fan Switches – Step-by-step pictures – Easy wiring diagrams and installation guide – Light and fan switch variations.

Electrical Panel Sizes and Circuit Wiring

We have installed a 100 amp breaker box in a new work shop, what size breakers do I attach the main lines to in the 200amp box…

Question – Cords and How to Identify the Individual Wires – Part 3

I think a hardware store employee gave me wrong advice about cords. One side is smooth, one is ridged; which is which?

Question – Cords and How to Identify the Individual Wires – Part 2

Smooth side, ridged side: Which is which?

See more at the Electrical Questions Category Listing.

Be sure to get your copy of my BIG Book:

Complete Guide to Home Electrical Wiring

Be sure to get your copy of my BIG Book:
Perfect for Homeowners, Students and Electricians
Includes:
Home Electrical Wiring - Room by Room
120 Volt Circuits
240 Volt Circuits
Multi-Wired Circuits
Wiring Methods for Installing Home Electrical Circuit Wiring
Electrical Codes for Home Electrical Wiring
....and much more.

Electrical Tips to Help You Wire it Right

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.

Residential Electrical Parts and Accessories

Light Switches

120volt Outlets

Circuit Breakers

Electrician Tools

Voltage Testers

More about: Electrical wire

How Many Electrical Wires In a Junction Box
How To Splice Electrical Wires
What Size Conduit For Electrical Wires
Splicing Electrical Wires Safely
How to Repair Damaged Electrical Wires
Methods for Splicing Electrical Wires
Using a Circuit Tracer to Detect a Broken Electrical Wire
What is the Correct Electrical Wire Size for Your Project?

How Many Electrical Wires In a Junction Box