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Electrical Wire and Cable

Electric Wire and Electrical Cable

electrical-wire ©Copyright
Summary: Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.


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




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

electrical wire - 14-2 romex-wire

electrical wire - 14-2

Wire for Outlets and Lighting

electrical wire - 14-3-romex-wire

electrical wire - 14-3 Romex wire

Wire for Lighting - 3-Way Switches
and Smoke Detectors

electrical wire - 12-2-romex-wire

electrical wire - 12-2 Romex wire

Wire for Outlet Receptacles

electrical wire - 12-3-romex-wire

electrical wire - 12-3 Romex wire

3-Wire Circuits - Kitchen / Garage Wire

electrical wire - 10-2-romex-wire

electrical wire - 10-2 Romex wire

Wire for Water Heaters - Small A/C

electrical wire - 10-3-romex-wire

electrical wire - 10-3 Romex wire

Wire for Dryer with 4-Wire Receptacle

electrical wire - 8-3-romex-wire

electrical wire - 8-3 Romex wire

Wire for Small Ovens




Common Wiring Fasteners and Components and What They are Used For

WIRE PROTECTION

PART DESCRIPTION WIRING PURPOSE and USE

electrical romex-staple

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

electrical wire-safety-plate

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

electrical wirenut-blue-large

Large Blue Wirenut

#14 thru #6 AWG
Min. 3 #12
Max. 2 #6 w/ 1 #12

electrical wirenut-gray-large

Large Gray Wirenut

#18 to #6 AWG
Min. 2 #12
Max. 6 #12

electrical wirenut-red

Red Wirenut

#18 thru #8 AWG
Min. 2 #18
Max. 4 #10

electrical wirenut-yellow

Yellow Wirenut

#18 thru #10 AWG
Min. 2 #18
Max. 3 #12

electrical wirenut-orange

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

electrical wire-crimp

Crimp Sleeve

Joining two or three #14 or #12 bare ground wires to form a "tail" for bonding plugs & switches

electrical green-ground-screw

Green Grounding Screw

Bond the ground wire using tapped ground access
#14 and #12 wires

electrical ground-clip

Grounding Clip

For older metal boxes without a ground screw access
#14 and #12 wire

electrical grounding-lug

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.



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