Wiring Methods

This chapter outlines the general requirements for wiring methods used in services, feeders, and branch circuits for electrical power and distribution within residential structures.

E3801 — General Requirements

E3801.1 Scope. This chapter covers the wiring methods for services, feeders and branch circuits for electrical power and distribution.

E3801.2 Allowable wiring methods. The allowable wiring methods for electrical installations shall be those listed in Table E380 1.2. Single conductors shall be used only where part of one of the recognized wiring methods listed in Table E3801.2. As used in this code, abbreviations of the wiring-method types shall be as indicated in Table E3801.2.

A table appears here in the adopted code. Refer to the official source for the full table.

E3801.3 Circuit conductors. All conductors of a circuit, including equipment grounding conductors and bonding conductors, shall be contained in the same raceway, trench, cable or cord.

E3801.4 Wiring method applications. Wiring methods shall be applied in accordance with Table E3801.4.

E3802 — Above-ground Installation Requirements

E3802.1 Installation and support requirements. Wiring methods shall be installed and supported in accordance with Table E3802.1.

E3802.2 Cables in accessible attics. Cables in attics or roof spaces provided with access shall be installed as specified in Sections E3802.2.1 and E3802.2.2.

E3802.2.1 Across structural members. Where run across the top offloorjoists, or run within 7 feet (2134 mm) offloor or floor joists across the face of rafters or studding, in attics and roof spaces that are provided with access, the cable shall be protected by substantial guard strips that are at least as high as the cable. Where such spaces are not provided with access by permanent stairs or ladders, protection shall only be required within 6 feet (1829 mm) of the nearest edge of the attic entrance. E3802.2.2 Cable installed through or parallel to framing members. Where cables are installed through or parallel to the sides of rafters, studs or floorjoists, guard strips and running boards shall not be required, and the installation shall comply with Table E3802.1.

E3802.2.1 Across structural members. Where run across the top offloorjoists, or run within 7 feet (2134 mm) offloor or floor joists across the face of rafters or studding, in attics and roof spaces that are provided with access, the cable shall be protected by substantial guard strips that are at least as high as the cable. Where such spaces are not provided with access by permanent stairs or ladders, protection shall only be required within 6 feet (1829 mm) of the nearest edge of the attic entrance.

E3802.2.2 Cable installed through or parallel to framing members. Where cables are installed through or parallel to the sides of rafters, studs or floorjoists, guard strips and running boards shall not be required, and the installation shall comply with Table E3802.1.

E3802.3 Exposed cable. In exposed work, except as provided for in Sections E3802.2 and E3802.4, cable assemblies shall be installed as specified in Sections E3802.3.1 and E3802.3.2.

E3802.3.1 Surface installation. Cables shall closely follow the surface of the building finish or running boards. E3802.3.2 Protection from physical damage. Where subject to physical damage, cables shall be protected by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means. Where passing through a floor, the cable shall be enclosed in rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit or other approved means extending not less than 6 inches (152 mm) above the floor. E3802.3.3 Locations exposed to direct sunlight. Insulated conductors and cables used where exposed to direct rays of the sun shall be listed or listed and marked, as being "sunlight resistant," or shall be covered with insulating material, such as tape or sleeving, that is listed or listed and marked as being"sunlight resistant."

E3802.3.1 Surface installation. Cables shall closely follow the surface of the building finish or running boards.

E3802.3.2 Protection from physical damage. Where subject to physical damage, cables shall be protected by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means. Where passing through a floor, the cable shall be enclosed in rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit or other approved means extending not less than 6 inches (152 mm) above the floor.

E3802.3.3 Locations exposed to direct sunlight. Insulated conductors and cables used where exposed to direct rays of the sun shall be listed or listed and marked, as being "sunlight resistant," or shall be covered with insulating material, such as tape or sleeving, that is listed or listed and marked as being"sunlight resistant."

E3802.4 In unfinished basements and crawl spaces. Where type SE or NM cable is run at angles with joists in unfinished basements and crawl spaces, cable assemblies containing two or more conductors ofsizes 6 AWe and larger and assemblies containing three or more conductors ofsizes 8 AWe and larger shall not require additional protection where attached directly to the bottom of the joists. Smaller cables shall be run either through bored holes injoists or on running boards. NM cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with Table E3802.1. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the where cable enters the raceway. The NM or SE cable sheath shall extend through the conduit or tubing and into the outlet or device box not less than ¼ inch (6.4 mm). The cable shall be secured within 12 inches (305 mm) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor.

A table appears here in the adopted code. Refer to the official source for the full table.

a. The metallic covering is impervious to moisture.b. A lead sheath or moisture-impervious jacket is provided under the metal covering.c. The insulated conductors under the metallic covering are listed for use in wet locations and a corrosion-resistantjacket is provided over the metallic

a. The metallic covering is impervious to moisture.b. A lead sheath or moisture-impervious jacket is provided under the metal covering.c. The insulated conductors under the metallic covering are listed for use in wet locations and a corrosion-resistantjacket is provided over the metallic

A table appears here in the adopted code. Refer to the official source for the full table.

E3802.5 Bends. Bends shall be made so as not to damage the wiring method or reduce the internal diameter of raceways.

For types NM and SE cable, bends shall be so made, and other handling shall be such that the cable will not be damaged and the radius ofthe curve ofthe inner edge ofany bend shall be not less than five times the diameter of the cable.

E3802.6 Raceways exposed to different temperatures. Where portions of a cable, raceway or sleeve are known to be subjected to different temperatures and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be filled with an approved material to prevent the circulation of warm air to a colder section of the raceway or sleeve.

E3802.7 Raceways in wet locations above grade. Where raceways are installed in wet locations abovegrade, the interior of such raceways shall be considered to be a wet location. Insulated conductors and cables installed in raceways in wet locations abovegrade shall be listed for use in wet locations.

E3803 — Underground Installation Requirements

E3803.1 Minimum cover requirements. Direct buried cable or raceways shall be installed in accordance with the minimum cover requirements of Table E3803.1.

E3803.2 Warning ribbon. Underground service conductors that are not encased in concrete and that are buried 18 inches (457 mm) or more below grade shall have their location identified by a warning ribbon that is placed in the trench not less than 12 inches (305 mm) above the underground installation.

E3803.3 Protection from damage. Direct buried conductors and cables emerging from the ground shall be protected by enclosures or raceways extending from the minimum cover

A table appears here in the adopted code. Refer to the official source for the full table.

distance below grade required by Section E3803.1 to a point at least 8 feet (2438 mm) above finished grade. In no case shall the protection be required to exceed 18 inches (457 mm) below finished grade. Conductors entering a building shall be protected to the point of entrance. Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in rigid metal conduit, intermediate metal conduit, Schedule 80 rigid nonmetallic conduit or the equivalent.

E3803.4 Splices and taps. Direct buried conductors or cables shall be permitted to be spliced or tapped without the use of splice boxes. The splices or taps shall be made by approved methods with materials listed for the application.

E3803.5 Backfill. Backfill containing large rock, paving materials, cinders, large or sharply angular substances, or corrosive material shall not be placed in an excavation where such materials cause damage to raceways, cables or other substructures or prevent adequate compaction of fill or contribute to corrosion of raceways, cables or other substructures. Where necessary to prevent physical damage to the raceway or cable, protection shall be provided in the form of granular or selected material, suitable boards, suitable sleeves or other approved means.

E3803.6 Raceway seals. Conduits or raceways shall be sealed or plugged at either or both ends where moisture will enter and contact live parts.

E3803.7 Bushing. A bushing, or terminal fitting, with an integral bushed opening shall be installed on the end of a conduit or other raceway that terminates underground where the conductors or cables emerge as a direct burial wiring method. A seal incorporating the physical protection characteristics of a bushing shall be considered equivalent to a bushing.

E3803.8 Single conductors. All conductors ofthe same circuit and, where present, the grounded conductor and all equipment grounding conductors shall be installed in the same raceway or shall be installed in close proximity in the same trench.

Exception: Where conductors are installed in parallel in raceways, each raceway shall contain all conductors of the same circuit including grounding conductors.

E3803.9 Ground movement. Where direct buried conductors, raceways or cables are subject to movement by settlement or frost, direct buried conductors, raceways or cables shall be arranged to prevent damage to the enclosed conductors or to equipment connected to the raceways.

E3803.10 Wet locations. The interior of enclosures or raceways installed underground shall be considered to be a wet location. Insulated conductors and cables installed in such enclosures or raceways in underground installations shall be listed for use in wet locations. Connections or splices in an underground installation shall be approved for wet locations.

E3803.11 Under buildings. Underground cable installed under a building shall be in a raceway.

Frequently asked questions

What types of electrical systems does Chapter 38 cover?

This chapter covers wiring methods for services, feeders, and branch circuits for electrical power and distribution.

Where can I find installation specifics for above-ground wiring?

Above-ground wiring methods must be installed and supported in accordance with the requirements detailed in Table E3802.1.

What are the minimum cover requirements for underground wiring?

Direct buried cable or raceways installed underground must comply with the minimum cover requirements specified in Table E3803.1.