Electrical Wire

Summary: 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

Home Electrical Wire and Romex Electrical Wire

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 Romex, also known as 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 Romex style 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 Romex wiring conductors 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


Audio about Home Electrical Wire and Cable

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

Size

Copper

Aluminum

#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

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 )

Please Note: This table is for Copper Wire Only:

Wire	Amperage
#14	15
#12	20
#10	30
#8	40

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Lets look at common home-electrical-wire, components, and typical uses.
Romex Wire	Name & Amps	Typical Use
		Receptacles and Lighting
		Lighting - 3-Way Switches and Smoke Detectors
		Receptacles
		3-Wire Circuits - Kitchen / Garage
		Water Heaters - Small A/C
		Dryers 4-Wire Receptacle
		Small Ovens
WIRE PROTECTION	DESCRIPTION	PURPOSE
	Romex Staple Fasten cables to wood structure every 4-1/2' and within 8 " of boxes.	7/16 - #14 Romex 9/16 - #12 & #10 Romex 1 - Inch for Larger Cables
	Safety Plate	Protect the wires in vulnerable areas [See How]
WIRENUTS & CONNECTORS	DESCRIPTION	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
GROUND BONDING	DESCRIPTION	PURPOSE
	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