# Conductor: Building Code Definition

> How the IPC 2009 define conductor, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/conductor/
- Last updated: 2026-09-07
- Data source: 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.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IPC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IPC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 28 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Conductor is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.” No other I-Code in this corpus defines it, so the IPC 2009 definition is the one to work from. The term is used in 28 chapters of this corpus, most often in Services (IRC 2009), Power and Lighting Distribution (IRC 2009), Branch Circuit and Feeder Requirements (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](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Conductor** — IPC 2009, Definitions:

> A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.

![Labeled code-term definition diagram: Conductor: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/conductor/diagram-1344.webp)

*How the IPC 2009 define conductor, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Conductor** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) chapter of the International Plumbing Code (IPC) 2009:

> A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.

## Where conductor is used in the code

The term appears in 28 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Services](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/services.md) | IRC 2009 | 245 |
| [Power and Lighting Distribution](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/power-and-lighting-distribution.md) | IRC 2009 | 215 |
| [Branch Circuit and Feeder Requirements](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/branch-circuit-and-feeder-requirements.md) | IRC 2009 | 152 |
| [General Requirements](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/general-requirements.md) | IRC 2009 | 115 |
| [Swimming Pools](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/swimming-pools.md) | IRC 2009 | 111 |
| [Electrical Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/electrical-definitions.md) | IRC 2009 | 63 |
| [Devices and Luminaires](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/devices-and-luminaires.md) | IRC 2009 | 47 |
| [Class 2 Remote-control, Signaling and Power-limited Circuits](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/class-2-remote-control-signaling-and-power-limited-circuits.md) | IRC 2009 | 38 |
| [Wiring Methods](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/wiring-methods.md) | IRC 2009 | 33 |
| [Storm Drainage](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/storm-drainage.md) | IPC 2009 | 18 |
| [Semiconductor Fabrication Facilities](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/semiconductor-fabrication-facilities.md) | IFC 2009 | 16 |
| [Aviation Facilities](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/aviation-facilities.md) | IFC 2009 | 6 |

_16 further chapters mention the term._

### The term in use

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

> The grounded conductor ampacity shall be not less than the maximum unbalance of the load and its size shall be not smaller than the required minimum grounding electrode conductor size specified in Table E3603.1.

— [IRC 2009 §E3603.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/services.md)

> Metal raceways, cable armor and other metal enclosures for conductors shall be mechanically joined together into a continuous electric conductor and shall be connected to all boxes, fittings and cabinets so as to provide effective electrical continuity.

— [IRC 2009 §E3904.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/power-and-lighting-distribution.md)

> 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.

— [IRC 2009 §E3701.2](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/branch-circuit-and-feeder-requirements.md)


## The terms conductor 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 conductor covers:

- **[Building Drain](https://harth.build/resources/glossary/building-drain.md)** — IRC 2009: The lowest piping that collects the discharge from all other drainage piping inside the house and extends 30 inches (762 mm) in developed length of pipe, beyond the exterior walls and conveys the drainage to the building sewer.
- **[Building](https://harth.build/resources/glossary/building.md)** — IBC 2009: Any structure used or intended for supporting or sheltering any use or occupancy.
- **[Drain](https://harth.build/resources/glossary/drain.md)** — IRC 2009: Any pipe that carries soil and water-borne wastes in a building drainage system.

## Conductor: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) cover the middle rows.

| Check | Where | Confirmed |
| --- | --- | --- |
| Read the definition in the adopted IPC | Definitions | |
| Re-check the requirement that uses it | Services (IRC 2009) | |
| Re-check the requirement that uses it | Power and Lighting Distribution (IRC 2009) | |
| Re-check the requirement that uses it | Branch Circuit and Feeder Requirements (IRC 2009) | |
| Re-check the requirement that uses it | General Requirements (IRC 2009) | |
| Confirm the dependent definition | Building Drain | |
| Confirm the dependent definition | Building | |
| Confirm the dependent definition | Drain | |
| 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](https://harth.build/resources/glossary.md)
- [Building Drain: Building Code Definition](https://harth.build/resources/glossary/building-drain.md)
- [Building: Building Code Definition](https://harth.build/resources/glossary/building.md)
- [Drain: Building Code Definition](https://harth.build/resources/glossary/drain.md)

## 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](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.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of conductor?

The International Plumbing Code (IPC) 2009 defines it in Definitions as: “A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.” 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 conductor?

In this corpus the term is used across 28 chapters, led by Services 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 counts as a conductor?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IPC 2009 states, in Definitions: “A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.” It is defined in IPC 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 is an IPC connector?

Connector is a separate defined term. The IBC 2009 defines it as: “A mechanical device for securing two or more pieces, parts or members together, including anchors, wall ties and fasteners.” That is not the same as conductor, which the IPC 2009 defines as “A pipe inside the building that conveys storm water from the roof to a storm or combined bUilding drain.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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