Electrical Code for Wire Type and Size
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How to Know What Wire Size and Type to use for Home Electrical Wiring – Continuing the circuit with the same wire size and type is essential to maintain the integrity of the circuit. © By: Dave Rongey |
Electrical Wire Size
[ad#block]Electrical Question: Is it legal to start a circuit with AC 12-2 and then mid circuit change the cable type to NM 12-2?
- The AC 12-2 does not have a separate insulated ground conductor however it only has the bare aluminum bonding strip.
- Also, where would the ground for the NM cable bond?
This Electrical Wiring Question came from: Eric, a Homeowner from Fairfax, Virginia.
Dave’s Reply:
Thanks for your electrical wiring question Eric.
How to Select the Right Size and Type of Electrical Wire
Maintaining Circuit Integrity
- Continuing the circuit with the same wire size and type is essential to maintain the integrity of the circuit.
- Bonding the circuit with any metal junction box using an approved grounding screw or method of attachment is required.
Wire Type Definitions In This Discussion
- AC Cable is Armored Cable, which is where individual wires are protected by a metal flex covering.
- NM Cable is Non-Metallic cable, which is where individual wires are protected by a plastic outer covering.
Components of Maintaining Circuit Integrity include Items within the Circuit that have the same Circuit Rating Factors, such as:
- Circuit Breaker
- Wire Size or Gauge
- Outer Wire Insulation Type
- Inner Wire Conductor Composition, Copper or Aluminum
- Wiring Junction Box or Enclosure
- Wiring Devices, Receptacle Outlet or Switch
The Dangers of Not Maintaining Electrical Circuit Integrity include:
- Circuit component overheating
- Combustion and Fire Danger
- Damage to devices connected to the circuit
- Damage to the building structure and personal property
- Electrical shock which can be fatal
The Following will assist you with your electrical question:
Electrical Panel Circuit Listing
Electrical circuit
Electric Circuit Listing
The size of the home electrical service panel is designed by calculating the square footage of the home and factoring in the code requirements for the electrical circuits that are required.
For more information about Electrical Code
Electrical Code
Home Electrical Code
Electrical Code Directory covering:
- AFCI Circuits
- Electrical Boxes
- Electrical Circuits
- Electrical Outlets
- GFCI Protection
- Grounding
- Electrical Panels and Services
- Underground Electrical Wiring
- Home Electrical Wiring
- Lighting
- Smoke Detectors
The following may also be helpful for you:
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Hi Brian,
When extending or replacing the wiring of an existing circuit it is important to maintain the same wire size or gauge of the same amperage rating. This will prevent confusion about the actual capacity of the circuit and will maintain the integrity of the original circuit. 14-2 is commonly a 15 amp circuit rating, and 12-2 is commonly a 20 amp rated circuit, so you can see that these wire sizes should not be installed within the same circuit.
When upgrading electrical systems of an older home it is often necessary to install new circuits to areas such as the kitchen and bathrooms and provide GFCI circuit protection as well.
Dave
I am adding a couple outlets to an older house, i believe the existing wire is 12-2 (larger diameter wire) can i extend from the existing outlet with a 14-2 wire? Both are romex.