Building Code Glossary
Branch Circuit: Building Code Definition
How the IRC 2009 define branch circuit, where the wording differs, and which chapters depend on the term.
On this page
Last updated September 7, 2026 · Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.
Direct answer
Branch circuit is a defined term in the International Residential Code (IRC) 2009, in Electrical Definitions. The code's own words are: “The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 12 chapters of this corpus, most often in Branch Circuit and Feeder Requirements (IRC 2009), Power and Lighting Distribution (IRC 2009), Swimming Pools (IRC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.
Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Branch Circuit — IRC 2009, Electrical Definitions:
The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
What must be verified before using this guidance?
Branch Circuit is defined once in this corpus, in the Electrical Definitions chapter of the International Residential Code (IRC) 2009:
The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).
Where branch circuit is used in the code
The term appears in 12 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Branch Circuit and Feeder Requirements | IRC 2009 | 77 |
| Power and Lighting Distribution | IRC 2009 | 24 |
| Swimming Pools | IRC 2009 | 21 |
| Services | IRC 2009 | 19 |
| Devices and Luminaires | IRC 2009 | 11 |
| Electrical Definitions | IRC 2009 | 11 |
| Appliance Installation | IRC 2009 | 4 |
| Wiring Methods | IRC 2009 | 4 |
| General Requirements | IRC 2009 | 3 |
| Building Services and Systems | IFC 2009 | 2 |
| Boilers, Water Heaters and Pressure Vessels | IMC 2009 | 1 |
| Scope and Administration | IRC 2009 | 1 |
The term in use
How the code actually writes about branch circuit, quoted from the 2009 text hosted here:
Where a branch circuit or a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit or feeder conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity equal to or greater than the noncontinuous load plus 125 percent of the continuous load.
A small-appliance branch circuit shall not serve more than one kitchen.
Where the bonding grid is connected to the equipment grounding conductor of the motor circuit in accordance with Section E4204.2, Item 6.1, the branch circuit wiring shall comply with Sections E4202.1 and E4205.5.
The terms branch circuit is built out of
The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what branch circuit covers:
- Overcurrent — IRC 2009: Any current in excess of the rated current of equipment or the ampacity of a conductor.
- Outlet — IRC 2009: A point on the wiring system at which current is taken to supply utilization equipment.
- Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.
Branch Circuit: what to open, and in what order
Every row is a document this term depends on. The ICC code library and the ICC adoption maps cover the middle rows.
| Check | Where | Confirmed |
|---|---|---|
| Read the definition in the adopted IRC | Electrical Definitions | |
| Re-check the requirement that uses it | Branch Circuit and Feeder Requirements (IRC 2009) | |
| Re-check the requirement that uses it | Power and Lighting Distribution (IRC 2009) | |
| Re-check the requirement that uses it | Swimming Pools (IRC 2009) | |
| Re-check the requirement that uses it | Services (IRC 2009) | |
| Confirm the dependent definition | Overcurrent | |
| Confirm the dependent definition | Outlet | |
| Confirm the dependent definition | Device | |
| Local amendment to any of the above | Jurisdiction's amendment list |
A research aid, not a code determination. The authority having jurisdiction decides which edition and which amendments apply.
Where can you explore related guidance?
- Explore all glossary guidance
- Overcurrent: Building Code Definition
- Outlet: Building Code Definition
- Device: Building Code Definition
Sources and method
Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The ICC code library publishes the current model text and the ICC adoption maps show which edition a jurisdiction has adopted; those sources control.
Source links
Frequently asked questions
What is the code definition of branch circuit?
The International Residential Code (IRC) 2009 defines it in Electrical Definitions as: “The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.
Which parts of the code depend on branch circuit?
In this corpus the term is used across 12 chapters, led by Branch Circuit and Feeder Requirements in the IRC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.
What is a branch circuit wire?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Electrical Definitions: “The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).” It is defined in IRC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
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