Updated 2026-09-07

Building Code Glossary

Feeder: Building Code Definition

How the IRC 2009 define feeder, 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.

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Direct answer

Feeder is a defined term in the International Residential Code (IRC) 2009, in Electrical Definitions. The code's own words are: “All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.” 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 8 chapters of this corpus, most often in Branch Circuit and Feeder Requirements (IRC 2009), Services (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?

Feeder — IRC 2009, Electrical Definitions:

All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.

Labeled code-term definition diagram: Feeder: Building Code Definition — How the IRC 2009 define feeder, where the wording differs, and which chapters depend on the term.

What must be verified before using this guidance?

Feeder is defined once in this corpus, in the Electrical Definitions chapter of the International Residential Code (IRC) 2009:

All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.

Where feeder is used in the code

The term appears in 8 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	33
Services	IRC 2009	17
Swimming Pools	IRC 2009	10
Wiring Methods	IRC 2009	4
Building Services and Systems	IFC 2009	2
Electrical Definitions	IRC 2009	2
Structural Design	IBC 2009	1
General Requirements	IRC 2009	1

The term in use

How the code actually writes about feeder, quoted from the 2009 text hosted here:

Feeder circuits that serve 100 percent of the dwelling unit load shall be sized in accordance with the procedures in Chapter 36.

— IRC 2009 §E3701.1

Conductors used as ungrounded service entrance conductors, service lateral conductors, and feeder conductors that serve as the main power feeder to a dwelling unit shall be those listed in Table E3603.1.

— IRC 2009 §E3603.1

An equipment grounding conductor shall be installed with the feeder conductors between the grounding terminal of the pool equipment panelboard and the grounding terminal of the applicable service equipment or source of a separately derived system.

— IRC 2009 §E4205.6

The terms feeder is built out of

The definition above leans on 5 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what feeder covers:

Service Equipment — IRC 2009: The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s), and their accessories, connected to the load end of the service conductors to a building or other structure, or an otherwise designated area, and intended to constitute …
Overcurrent — IRC 2009: Any current in excess of the rated current of equipment or the ampacity of a conductor.
Equipment — IRC 2009: All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for buildings.
Service — IRC 2009: The conductors and equipment for delivering energy from the serving utility to the wiring system of the premises served.
Branch — IRC 2009: Any part of the piping system other than a riser, main or stack.

Feeder: 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	Services (IRC 2009)
Re-check the requirement that uses it	Swimming Pools (IRC 2009)
Re-check the requirement that uses it	Wiring Methods (IRC 2009)
Confirm the dependent definition	Service Equipment
Confirm the dependent definition	Overcurrent
Confirm the dependent definition	Equipment
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.

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 feeder?

The International Residential Code (IRC) 2009 defines it in Electrical Definitions as: “All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.” 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 feeder?

In this corpus the term is used across 8 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 the NEC code for feeder size?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Electrical Definitions: “All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.” 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.

What does IRC mean in building code?

Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as feeder, which the IRC 2009 defines as “All circuit conductors between the service equipment, or the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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