PEC Chapter 3
Manholes and Handhole Enclosures
A box or conduit body shall not be required for conductors in manholes or handhole enclosures, except where connecting to electrical equipment. The installation shall comply with the provisions of Part 1.10.5 for manholes, and 3.14.2.16 for handhole enclosures.
Wiring Methods with Interior Access
A box or conduit body shall not be required for each splice, junction, switch, pull, termination, or outlet points in wiring methods with removable covers, such as wireways, multioutlet assemblies, auxiliary gutters, and surface raceways. The covers shall be accessible after installation.
Embedded
A box or conduit body shall not be required for splices where conductors are embedded as permitted in 4.24.5.7, 4.24.5.8(D), and 4.27.3.6(A)
Luminaires
A box or conduit body shall not be required where a luminaire is used as a raceway as permitted in 4.10.6.17
Enclosures
A box or conduit body shall not be required where a splice, switch, terminal, or pull point is in a cabinet or cutout box, in an enclosure for a switch or over-current device as permitted in 3.12.1.8, in a motor controller as permitted in 4.30.1.1 O(A), or in a motor control center
Type MI Cable
A box or conduit body shall not be required where accessible fittings are used for straight through splices in mineral-insulated metal-sheathed cable.
Protection
A box or conduit body shall not be required where cables enter or exit from conduit or tubing that is used to provide cable support or protection against physical damage. A fitting shall be provided on the end( s) of the conduit or tubing to protect the cable from abrasion.
Box, Conduit Body, or Fitting
A box, conduit body, or terminal fitting having a separately bushed hole for each conductor shall be used wherever a change is made from conduit, electrical metallic tubing, electrical nonmetallic tubing, nonmetallic-sheathed cable, Type AC cable, Type MC cable, or mineral-insulated, metalsheathed cable and surface raceway wiring to open wiring or to concealed knob-and-tube wiring
FCC System
A complete wiring system for branch circuits that is designed for installation under carpet squares.
Cable Connector
A connector designed to join Type FCC cables without using a junction box.
Top Shield
A grounded metal shield covering undercarpet components of the FCC system for the purposes of providing protection against physical damage
Flexible Metallic Tubing (FMT)
A metal raceway that is circular in cross section, flexible and liquidtight without a nonmetallic jacket
Bottom Shield
A protective layer that is installed between the floor and Type FCC flat conductor cable to protect the cable from physical damage and may or may not be incorporated as an integral part of the cable
Liquidtight Flexible Metal Conduit (LFMC)
A raceway of circular cross section having an outer liquidtight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core with associated couplings, connectors, and fittings for the installation of electric conductors.
Flexible Metal Conduit (FMC)
A raceway of circular cross section made of helically wound, formed, interlocked metal strip.
Service-Entrance Cable
A single conductor or multiconductor assembly provided with or without an overall covering, primarily used for services, and of the following types:
Medium Voltage Cable, Type MV
A single or multiconductor solid dielectric insulated cable rated 2001 volts or higher
Intermediate Metal Conduit (IMC)
A steel threadable raceway of circular cross section designed for the physical protection and routing of conductors and cables and for use as an equipment grounding conductor when installed with its integral or associated coupling and appropriate fittings.
Rigid Metal Conduit (RMC)
A threadable raceway of circular cross section designed for the physical protection and routing of conductors and cables and for use as an equipment grounding conductor when installed with its integral or associated coupling and appropriate fittings
Integral Enclosure
A wiring device with integral enclosure identified for the use, having brackets that securely fasten the device to walls or ceilings of conventional on-site frame construction, for use with nonmetallic-sheathed cable, shall be permitted in lieu of a box or conduit body.
Conductors in Parallel
Aluminum, copper-clad aluminum, or copper conductors, for each phase, polarity, neutral, or grounded circuit shall be permitted to be connected in parallel
Transition Assembly
An assembly to facilitate connection of the FCC system to other wiring systems, incorporating (1) a means of electrical interconnection and (2) a suitable box or covering for providing electrical safety and protection against physical damage
Insulating End
An insulator designed to electrically insulate the end of a Type FCC cable.
Equipment
An integral junction box or wiring compartment as part of approved equipment shall be permitted in lieu of a box.
Direct-Buried Conductors
As permitted in 3.0.1.5(E), a box or conduit body shall not be required for splices and taps in direct-buried conductors and cables.
Insulated Devices
As permitted in 334.40(B), a box or conduit body shall not be required for insulated devices supplied by nonmetallic-sheathed cable.
Thermal Resistivity
As used in this Code, the heat transfer capability through a substance by conduction.
WIRING METHODS AND MATERIALS
CHAPTER 3
(A) Single Conductors (B) Conductors of the Same Circuit (C) Conductors of Different Systems
Conductors
Corrosive Conditions
Conductors exposed to oils, greases, vapors, gases, fumes, liquids, or other substances having a deleterious effect on the conductor or insulation shall be of a type suitable for the application.
Mechanical and Electrical Continuity - Conductors. GENERAL
Conductors in raceways shall be continuous between outlets, boxes, devices, and so forth. There shall be no splice or tap within a raceway unless permitted
Nonferrous Wiring Methods
Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath, where run in different raceways, auxiliary gutters, cable trays, trenches, cables, or cords, shall comply with the provisions of 3.0. l.20(B)
(1) 1000 Volts, Nominal, or Less (2) Over 1000 Volts, Nominal
Conductors of Different Systems
1000 Volts, Nominal, or Less
Conductors of ac and dc circuits, rated 1000 volts, nominal, or less, shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway.
Over 1000 Volts, Nominal
Conductors of circuits rated over 1000 volts, nominal, shall not occupy the same equipment wiring enclosure, cable, or raceway with conductors of circuits rated 1 000 volts, nominal, or less unless otherwise permitted in 3.0.1.3(C)(2)(a) through (C)(2)( d)
(1) Paralleled Installations (2) Grounding and Bonding Conductors (3) Nonferrous Wiring Methods (4) Column-Width Panelboard Enclosures
Conductors of the Same Circuit
Paralleled Installations
Conductors shall be permitted to be run in parallel in accordance with the provisions of 3.10.2.l(H)
Direct-Burial Conductors
Conductors used for direct-burial applications shall be of a type identified for such use. Cables rated above 2 000 volts shall be shielded.
Electrical Ducts
Electrical conduits, or other raceways round in cross section, that are suitable for use underground or embedded in concrete
Grounding and Bonding Conductors
Equipment grounding conductors shall be permitted to be installed outside a raceway or cable assembly where in accordance with the provisions of 2.50.7.l(C)
Mechanical and Electrical Continuity - Conductors. DEVICE REMOVAL
In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.
Dry Locations
Insulated conductors and cables used in _______________ shall be any of the types identified in this Code.
Dry and Damp Locations
Insulated conductors and cables used in ___________________ shall be Types FEP, FEPB, MTW, PFA, RHH, RHW, RHW-2, SA, THHN, THW, THW-2, THHW, THWN, THWN-2, TW, XHH, XHHW, XHHW-2, Z, or ZW.
wet locations
Insulated conductors and cables used in__________________ shall comply with one of the following: (1) Be moisture-impervious metal-sheathed (2) BetypesMTW, RHW,RHW-2, TW, THW, THW2, THHW, THWN, THWN-2, XHHW, XHHW-2, zw (3) Be of a type listed for use in ___________
Locations Exposed to Direct Sunlight
Insulated conductors or cables used where exposed to direct rays of the sun shall comply with (D)(l) or (D)(2)
At least 150 mm of free conductor, switch point is less than 200 mm, conductor shall be long enough to extend at least 75 mm outside the opening
Length of Free Conductors at Outlets, Junctions, and Switch Points
Voltage- SHALL BE USED FOR 1000 VOLTS, NOMINAL, OR LESS Temperature- IN ACCORDANCE WITH TEMPERATURE LIMITATION OF CONDUCTORS
Limitations
Metal Shield Connections
Means of connection designed to electrically and mechanically connect a metal shield to another metal shield, to a receptacle housing or self-contained device, or to a transition assembly
Shielding
Nonshielded, ozone-resistant insulated conductors with a maximum phase-to-phase voltage of 5000 volts shall be permitted in Type MC cables in industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation.
Openings to Be Closed
Openings through which conductors enter shall be closed in an approved manner.
Round Boxes
Round boxes shall not be used where conduits or connectors requiring the use of locknuts or bushings are to be connected to the side of the box
A. ALL WIRING INSTALLATIONS B. INTEGRAL PARTS OF EQUIPMENT C. METRIC DESIGNATORS AND TRADE SIZES
SCOPE
Type SE
Service-entrance cable having a flameretardant, moisture-resistant covering.
Type USE
Service-entrance cable, identified for underground use, having a moisture-resistant covering, but not required to have a flame-retardant covering
Covers Required FOR OVER 1000 VOLTS, NOMINAL
Suitable covers shall be installed on all boxes, fittings, and similar enclosures to prevent accidental contact with energized parts or physical damage to parts or insulation. ARTICLE
Surface Extensions
Surface extensions shall be made by mounting and mechanically securing an extension ring over the box. Equipment grounding shall be in accordance with Part 2.50.6.
confine the voltage stresses to the insulation, dissipate insulation leakage current, drain off the capacitive charging current, and carry ground-fault current
The primary purposes of shielding
Column-Width Panelboard Enclosures
Where an auxiliary gutter runs between a column-width panelboard and a pull box, and the pull box includes neutral terminations, the neutral conductors of circuits supplied from the panelboard shall be permitted to originate in the pull box.
Cables
Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.
Metal Cabinets, Cutout Boxes, and Meter Socket Enclosures
Where metal enclosures within the scope of this article are installed with messenger-supported wiring, open wiring on insulators, or concealed knoband-tube wiring, conductors shall enter through insulating bushings or, in dry locations, through flexible tubing extending from the last insulating support and firmly secured to the enclosure.
Fitting
identified for the use shall be permitted in lieu of a box or conduit body where conductors are not spliced or terminated within the fitting. The fitting shall be accessible after installation.
Thermal resistivity
reciprocal of thermal conductivity and is designated Rho, which is expressed in the units °C-cm/W.
BOX
shall be installed at each outlet and switch point for concealed knob-and-tube wiring.
Bushing
shall be permitted in lieu of a box or terminal where the conductors emerge from a raceway and enter or terminate at equipment, such as open switchboards, unenclosed control equipment, or similar equipment.
FITTINGS AND CONNECTORS
shall be used only with the specific wiring methods for which they are designed and listed. Where the wiring method is conduit, tubing, Type AC cable, Type MC cable, Type MI cable, nonmetallic-sheathed cable, or other cables, a box or conduit body shall be installed at each conductor splice point, outlet point, switch point, junction point, termination point, or pull point, unless otherwise permitted in 3.0.l.15(A) through (L).
Damp and Wet Locations, 6 MM
surface-type enclosures within the scope of this article shall be placed or equipped so as to prevent moisture or water from entering and accumulating within the cabinet or cutout box. SHALL BE MOUNTED SO THERE IS AT LEAST _______ AIRSPACE BETWEEN THE ENCLOSURE AND THE WALL OR OTHER SUPPORTING SURFACES.
