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Electrical Wire and Cable
Electrician Training Electrical Certification wiring recessed light fixtures Electrical Wiring Electrical Troubleshooting and Electrical Repairs wire outdoor light fixture Home Electrical Wiring Diagrams
wiring home generator and transfer switch wiring a 220 volt range cord outlet Wiring for GFCI Outlets Wiring Outlets and a Switched Outlet Wiring and Installing Ceiling Fans and Remote Controls wire dimmer switch wiring diagrams for switches wiring a dryer cord and 220 outlet circuit breaker panel
Electrical Wire and Cable

What is the Electrical Wire Capacity

electrical-wire-code
Summary: The amperage capacity of electrical wire is determined by a few factors. The insulation materials used to protect the actual wire conductor are an important factor when selecting an electrical wire or cable. The following table demonstrates Standard Over Current Devices with 75 Degree Rated Terminals.


Selecting Wire Sizes for Electrical Wiring




Electrical Wire Capacities

It is essential to understand that there are allowable ampacities of insulated wire conductors.

The insulation materials used to protect the actual wire conductor are designed for specific applications.

Some types of wire insulation protect the wire against overheating and external elements such as direct sunlight exposure, moisture as well as some corrosive substances, to mention just a few.

Not all wire insulation types are designed the same, therefore they have specific amperage capacities.

The wire or conductor size and type is determined by the by the specific application and the load requirement. Other considerations that will affect the wire size may be the total length of the run of wire to be installed and if the wire will be installed into conduit or in an open air environment.
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.

Standard Over Current Devices with 75 Degree Rated Terminals
Circuit
Size
Copper Cable
Type NM, NM-B
Copper Cable
Type SE, USE
Aluminum Cable
Type SE, USE
15 #14 - -
20 #12 #12 #12
25 #10 #12 #10
30 #10 #10 #10
35 #8 #8 #8
40 #8 #8 #8
45 #6 #8 #6
50 #6 #8 #6
55 #6 #6 #4
60 #4 #6 #4
65 #4 #6 #4
70 #4 #4 #3
75 #3 #4 #3
80 #3 #3 #2
85 #3 #3 #2
90 #2 #3 #2
100 #1 #3 #1
115 1/0 #2 1/0
120 1/0 #1 1/0
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Electrical Tip

The Safest Way to Test Electrical Devices and Identify Electric Wiring!

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, [amazon.com], I use for the detection of Standard 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.

Electrical Code Questions and Answers