Code Article 110
110.26 Spaces About Electrical Equipment
Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.
110.16
Arc-Flash Hazard Warning
110.24
Available Fault Current
110.19 Light and Power from Railway Conductors
Circuits for lighting and power shall not be connected to any system that contains trolley wires with a ground return. Exception: Such circuit connections shall be permitted in car houses, power houses, or passenger and freight stations operated in connection with electric railways.
110.7 Wiring Integrity
Completed wiring installations shall be free from short circuits, ground faults, or any connections to ground other than as required as permitted elsewhere in this Code.
110.6 Conductor Sizes
Conductor sizes are expressed in American Wire Gage (AWG) or in circular mils.
110.5 Conductors
Conductors normally used to carry current shall be of copper or aluminum unless otherwise provided in this code. Where the conductor material is not specified, the sizes given in this code shall apply to copper conductors. Where other materials are used, the size shall be changed accordingly.
110.14 (B) Splices
Conductors shall be spliced or joined with splicing devices identified for the use or by brazing, welding, or soldering with a fusible metal or alloy. Soldered splices shall first be spliced or joined as as to be mechanically and electrically secure without solder and then be soldered. All splices and joints and the free ends of conductors or with an identified insulating device. Wire connectors or splicing means installed on conductors for direct burial shall be listed for such use.
110.13 (A) Mounting
Electrical equipment shall be firmly secured to the surface on which it is mounted. Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall not be used.
110.13 (B) Cooling
Electrical equipment that depends on the natural circulation of air and convection principles for cooling of exposed surfaces shall be installed so that room airflow over such surfaces is not prevented by walls or by adjacent installed equipment. For equipment designed for floor mounting, clearance between top surfaces and adjacent surfaces shall be provided to dissipate rising warm air. Electrical equipment provided with ventilating openings shall be installed so that walls or other obstructions do not prevent the free circulation of air through the equipment.
110.21 (A)
Equipment Markings
110.22 (B) Engineered Series Combination Systems
Equipment enclosures for circuit breakers or fuses applied in compliance with series combination ratings selected under engineering supervision in accordance with 240.86(A) shall be legibly marked in the field as directed by the engineer to indicate the equipment has been applied with a series combination rating. The marking shall meet the requirements in 110.21(B) and shall be readily visible and state the following : CAUTION - ENGINEERED SERIES COMBINATION SYSTEM RATED _____ AMPERES. IDENTIFIED REPLACEMENT COMPONENTS REQUIRED.
110.3
Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment
110.22
Identification of Disconnecting Means
110.25 Lockable Disconnecting Means
If a disconnecting means is required to be lockable open elsewhere in this Code, it shall be capable of being locked in the open position. The provisions for locking shall remain in place with or without the lock installed. Exception: Locking provisions for a cord-and-plug connection shall not be required to remain in place without the lock installed.
110.3 (B) Installation and Use
Listed or labeled equipment shall be installed and used in a accordance with any instructions included in the listing or labeling.
110.21
Marking
110.13
Mounting and Cooling of Equipment
110.18 Arcing Parts
Parts of electrical equipment that in ordinary operation produce arcs, sparks, flames or molten metal shall be enclosed or separated and isolated from all combustible material
110.14 (2) Separate Connector Provisions
Separately installed pressure connectors shall be used with conductors at the ampacities not exceeding the ampacity at the listed and identified temperature rating of the connector.
110.24 (A) Field Marking
Service equipment at other than dwelling units shall be legibly marked in the field with the maximum available fault current. The field marking(s) shall include the date the fault-current calculation was performed and be of sufficient durability to withstand the environment involved. The calculation shall be documented and made available those authorized to design, install, inspect, maintain, or operate the system.
110.2 Approval
The conductors and equipment required or permitted by this code shall be acceptable only if approved
110.26 (1) Depth of Working Space
The depth
110.21 (1) General
The manufacturers name, trademark, or other descriptive marking by which the organization responsible for the product can be identified shall be placed on all electrical equipment. Other markings that indicate voltage, current, wattage, or other ratings shall be provided as specified elsewhere in this Code. The marking or label shall be of sufficient durability to withstand the environment involved.
110.1 Scope
This article covers general requirements for the examination and approval, installation and use, access to and spaces about electrical conductors and equipment; enclosures intended for personnel entry; and tunnel installations.
110.4 Voltages
Throughout this code, the voltage considered shall be that at which the circuit operates. The voltage rating of electrical equipment shall not be less than the nominal voltage of a circuit to which it is connected.
110.11 Deteriorating Agents
Unless identified for use in the operating environment, no conductors or equipment shall be located in damp or wet locations; where exposed to gases, fumes, vapors, liquids, or other agents that have a deteriorating effect on the conductors or equipment; or where exposed to excessive temperatures. Equipment not identified for outdoor use and equipment identified only for indoor use, such as "dry locations," :indoor use only," "damp locations," or enclosure Types 1, 2, 5, 12, 12K, and/or 13, shall be protected against damage from the weather during construction.
110.12 (A) Unused Openings
Unused openings, other than those intended for the operation of equipment, those intended for mounting purposes, or those permitted as part of the design for listed equipment, shall be closed to afford protection substantially equivalent to the wall of the equipment. Where metallic plugs or plates are used with nonmetallic enclosures, they shall be recessed at least 6 mm (1/4 in.) from the outer surface of the enclosure.
110.14 (D) Installation
Where a tightening torque is indicated as a numeric value on equipment or in installation instructions provided by the manufacturer, a calibrated torque tool shall be used to achieve the indicated torque value, unless the equipment manufacturer has provided installation instructions for an alternative method of achieving the required torque.
110.26(A) Working Space
Working space for equipment operating at 1000 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall be comply with the dimensions of 110.26(A)(1), (A)(2), (A)(3), (A)(4) or as required or permitted elsewhere in this Code.
110.8 Wiring Methods
Only wiring methods recognized as suitable are included in this Code. The recognized methods of wiring shall be permitted to be installed in any type of building or occupancy, except as otherwise provided in this code.
110.14 (C) Temperature Limitations
The temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device. Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.
110.24 (B) Modifications
When modifications to the electrical installation occur that affect the maximum available fault current at the service, the maximum available fault current shall be verified or recalculated as necessary to ensure the service equipment ratings are sufficient for the maximum available fault current at the line terminals of the equipment. The required field marking(s) in 110.24(A) shall be adjusted to reflect the new level of maximum available fault current. Exception: The field marking requirements in 110.24(A) and 110.24(B) shall not be required in industrial installations where conditions of maintenance and supervision ensure that only qualified persons service the equipment.
110.21 (B) Field-Applied Hazard Markings
Where caution, warning, or danger signs or labels are required by this Code, the labels shall meet the following requirements. (1) The marking shall warn of the hazards using effective words, colors, symbols, or any combination thereof. (2) The label shall be permanently affixed to the equipment or wiring method and shall not be handwritten. Exception to (2): Portions of labels or markings that are variable, or that could be subject to changes, shall be permitted to be handwritten and shall be legible. (3) The label shall be of sufficient durability to withstand the environment involved.
110.22 (A) General
Each disconnecting means shall be legibly marked to indicate its purpose is evident. The marking shall be of sufficient durability to withstand the environment involved.
110.9 Interrupting Rating
Equipment intended to interrupt current at fault levels shall have an interrupting rating at nominal circuit voltage at least equal to the current that is available at the line terminals of the equipment. Equipment intended to interrupt current at other than fault levels shall have an interrupting rating at nominal circuit voltage at least equal to current that must be interrupted.
110.14 (A) Terminals
Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors. Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.
110.16 (A) General
Electrical equipment, such as switchboards, switchgear, panelboards, industrial control panels, meter socket enclosures, and motor control centers, that is in other than dwelling units and is likely to require examination, adjustment, servicing, or maintenance while energized, shall be field or factory marked to warn qualified persons of potential electric arc flash hazards. The marking shall meet the requirements in 110.21 (B) and shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment.
110.12 (B) Integrity of Electrical Equipment and Connections
Internal parts of electrical equipment, including busbars, wiring terminals, insulators, and other surfaces, shall not be damaged or contaminated by foreign materials such as paint, plaster, cleaners, abrasives, or corrosive residues. There shall be no damaged parts that may adversely affect safe operation or mechanical strength of the equipment such as parts that are broken; bent; cut; or deteriorated by corrosion, chemical action, or overheating.
110.15 High-Leg Marking
On a 4-wire, delta-connected system where the midpoint of one phase winding is grounded, only the conductor or busbar having the higher phase voltage to ground shall be durable and permanently marked by an outer finish that is orange in color or by other effective means. Such identification shall be placed at each point on the system where a connection is made if the grounded conductor is also present.
110.22 (C) Tested Series Combination Systems
Equipment enclosures for circuit breakers or fuses applied in compliance with the series combination ratings marked on the equipment by the manufacturer in accordance with 240.86(B) shall be legibly marked in the field to indicate the equipment has been applied with a series combination rating. The marking shall meet the requirements in 110.21(B) and shall be readily visible and state the following: CAUTION - SERIES COMBINATION SYSTEM RATED _____AMPERES. IDENTIFIED REPLACEMENT COMPONENTS REQUIRED.
110.14 Electrical Connections
Because of different characteristics of dissimilar metals, devices such as pressure terminal or pressure splicing connectors and soldering lugs shall be identified for the material of the conductor and shall be properly installed and used. Conductors of dissimilar metals shall not be intermixed in a terminal or splicing connector where physical contact occurs between dissimilar conductors (such as copper and aluminum, copper and copper-clad aluminum, or aluminum and copper-clad aluminum), unless the device is identified for the purpose and conditions of use. Materials such as solder, fluxes, inhibitors, and compounds, where employed, shall be suitable for the use and shall be of a type that will not adversely affect the conductors, installation, or equipment. Connectors and terminals for conductors more finely stranded that Class B and Class C stranding as shown in Chaper 9, Table 10, shall be identified for specific conductor class or classes.
110.12 Mechanical Execution of Work
Electrical equipment shall be installed in a neat and workmanlike manner.
110.3 (A) Examination
In judging equipment, considerations such as the following shall be evaluated: (1) Suitability for installation and use in conformity with the provisions of this code. IN#1: Equipment may be new, reconditioned, refurbished, or re-manufactured. IN#2: Suitability of equipment use may be identified by a description marked on or provided with a product to identify the suitability of the product for a specific purpose, environment, or application. Special conditions of use or other limitations and other pertinent information may be marked on the equipment, included in the product instructions, or included in the appropriate listing and labeling information. Suitability of equipment may be evidenced by listing or labeling. (2) Mechanical strength and durability, including, for parts deigned to enclose and protect other equipment, the adequacy of the protection thus provided. (3) Wire-bending and connection space (4) Electrical Installation (5) Heating effects under normal conditions of use and also under abnormal conditions likely to arise in service (6) Arcing effects (7) Classification by type, size, voltage, current capacity, and specific use (8) Other factors that contribute to the practical safeguarding of persons using or likely to come in contact with the equipment.
110.16 (B) Service Equipment
In other than dwelling units, in addition to the requirements in (A), a permanent label shall be field or factor applied to service equipment rated 1200 amps or more. The label shall meet the requirments of 110.21 (B) and contain the following information: (1)Nominal system voltage (2)Available fault current at the service overcurrent protective devices (3)The clearing time of service overcurrent protective devices based on the available fault current at the service equipment. (4)The date the label was applied Exception:Service equipment labeling shall not be required if an arc flash label is applied in accordance with acceptable industry practice
110.3 (C) Listing
Product testing, evaluation, and listing (product certification) shall be performed by recognized qualified electrical testing laboratories and shall be in accordance with applicable product standards recognized as achieving equivalent and effective safety for equipment installed to comply with this code IN: The Occupational Safety and Health Administration (OSHA) recognizes qualified electrical testing laboratories that perform evaluations, testing, and certification of certain products to ensure that they meet the requirements of both the construction and general industry OSHA electrical standards. If the listing (product certification) is done under a qualified electrical testing laboratory program, this listing mark signifies that the tested and certified product complies with the requirements of one or more appropriate product safety test standards.
110.21 (2) Reconditioned Equipment
Reconditioned equipment shall be marked with the name, trademark, or other descriptive marking by which the organization responsible for reconditioning the electrical equipment can be identified, along with the date of the reconditioning. Reconditioned equipment shall be identified as "reconditioned" and approval of the reconditioned equipment shall not be based solely on the equipment's original listing. Exception: In industrial occupancies, where conditions of maintenance and supervision ensure that only qualified persons service the equipment, the markings indicated in 110.21(A)(2) shall not be required. IN: Industry standards are available for application of reconditioned and refurbished equipment. Normal02
110.14 (1) Equipment Provisions
The determination of termination provisions of equipment shall be based on 110.14(C)(1)(a) or (C)(1)(b). Unless the equipment is listed and marked otherwise, conductor ampacities used in determining equipment termination provision shall be based on Table 310.15(B)(16) as appropriately modified by 310.15(B)(7) (a) Termination provision of equipment for circuits rates 100 amperes or less, or marked for 14 AWG through 1 AWG conductors, shall be used only for one of the following: (1) Conductors rates 60C (140F) (2)Conductors with higher temperature ratings, provided the ampacity of such conductors is determined based on the 60C (140F) ampacity of the conductor size used. (3)Conductors with higher temperature ratings if the equipment is listed and identified for use with usch conductors. (4) for motors marked with design letters B, C, or D, conductors having an insulation rating of 75C (167F) or higher shall be permitted to be used, provided the ampacity of such conductors does not exceed the 75C (167F) ampacity. (b) Termination provisions of equipment for circuits rated over 100 amperes, or marked for conductors larger thatn 1 ARG, shall be used only for one of the following: (1) Conductors rated 75C (167F) (2)Conductors with higher temperature ratings, provided the ampacity of such conductors does not exceed the 75C (167F) ampacity if the equipment is listed and identified for use with such conductors.
110.10 Circuit Impedance, Short-Circuit Current Ratings, and Other Characteristics
The overcurrent protective devices, the total impedance, the equipment short-circuit current ratings, and other characteristics of the circuit to be protected shall be selected and coordinated to permit the circuit protective devices used to clear a fault to do so without extensive damage to the electrical equipment of the circuit. This fault shall be assumed to be either between two or more of the circuit conductors or between any circuit conductor and the equipment grounding conductor(s) permitted in 250.118. Listed equipment applied in accordance with their listing shall be considered to meet the requirements of this section.
110.23 Current Transformers
Unused current transformers associated with potentially energized circuits shall be short circuited.