1、AN AMERICAN NATIONAL STANDARDNECA 407-2015 Standard forInstalling and Maintaining PanelboardsPublished byNational Electrical Contractors AssociationStandard forInstalling and Maintaining PanelboardsNECA 407-2015An AmericanNational StandardPublished byNational Electrical Contractors AssociationNOTICE
2、 OF COPYRIGHTThis document is copyrighted by NECAReproduction of these documents either in hard copy or soft (including posting on the web) is prohibited without copyright permission. For copyright permission to reproduce portions of this document, please contact NECA Standards including buses, conn
3、ectors, terminals, and/or lugs, automatic overcurrent devices such as circuit breakers, fuses, or both, and equipped with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet, cutout box, or enclosure placed in or against a wall or partition and a
4、ccessible only from the front.Surface-Mounted Panelboard A panelboard that is installed on the surface of a wall, partition, or similar construction, such that the cabinet is exposed on the mounting surface.2. Definitionsn 41. ScopeBefore performing cleaning, inspections, testing, maintenance, or re
5、pairs, electrically isolate conductors and equipment in accordance with established written procedures. All work and actions must conform to the requirements of NFPA 70E, Standard for Electrical Safety in the Workplace.The process of de-energizing conductors and equipment is considered “live” work a
6、nd can result in an arc flash due to equipment failure. When de-energizing conductors and equipment, follow safety procedures for working on or near live circuits. Failure to observe these precautions may result in severe personal injury or death.3.1 GeneralFor electrical equipment to work properly,
7、 it must be handled carefully and installed, operated, and maintained correctly. Neglecting fundamental installation and maintenance requirements can lead to personal injury or death, and damage to conductors, electrical equipment, and other property.Consider all circuits and ungrounded and grounded
8、 metal parts of equipment and devices to be energized at the highest voltage to which they are exposed unless they are de-energized, tested, locked out of operation, and red tagged in accordance with OSHA requirements.Do not work on energized conductors or equipment. Electrically isolate conductors
9、and equipment in accordance with established procedures and manufacturers instructions.Use care in opening and closing doors to energized equipment. Conductors and terminations may be exposed and within the reach of openings.Do not enter equipment enclosures when components are energized. Do not rem
10、ove access covers, doors, or panels when equipment is energized. Do not expose conductors, connections, or terminations when components are energized. Using established safety procedures, guard energized conductors and equipment in close proximity to work.3.2 Safe Work PracticesPerform preliminary i
11、nspections and tests prior to beginning work to determine existing conditions. Check existing conditions against available record documents.Visually verify all cable connections to equipment. Confirm that supply and load cables are connected properly. Keep in mind that transposed cables may be conne
12、cted to different terminals than expected.Resolve discrepancies between installed conditions and electrical drawings. Have drawings corrected, if required. Provide warning labels on equipment and cables where necessary to indicate unexpected and potentially hazardous conditions.Maintain as much dist
13、ance as practical from equipment and devices that may arc during operation or handling, but not less than the arc flash protection boundary specified in NFPA 70E.Use insulated hand tools when working on or around energized equipment. Use only properly rated tools for the energy present. Maintain too
14、l inventories to ensure that all tools are accounted for prior to energizing equipment.Ensure that egress from the work area is unobstructed, and that fire extinguishers approved for use in electrical fires are readily available.3. Safety Procedures5 nStandard for Installing and Maintaining Panelboa
15、rds NECA 407Do not make any modifications to the equipment or attempt to operate with interlocks or safety barriers removed. Engage lock-bars for compartment doors so equipped to prevent doors from accidentally closing.3.3 Personal Protective Equipment (PPE)Use appropriate Personal Protective Equipm
16、ent (PPE) and established safety procedures when working on or near energized electrical equipment or equipment that has not been de-energized, tested, grounded, locked out of operation, and red tagged in accordance with NFPA 70E.Wear appropriate PPE in accordance with the incident energy levels of
17、the equipment.Wear 100 percent natural fiber clothing or flame resistant apparel. Do not wear conductive articles such as watches, rings, or necklaces.3.4 De-Energizing Electrical EquipmentFollow all manufacturers instructions and recommendations for electrically isolating equipment and components.
18、Render equipment electrically safe. Follow lock-out/tag-out procedures. Disconnect all sources of power before opening any enclosures or compartments. Verify that source circuit breakers and switches are open.Identify all sources of power to the conductors and equipment. Interrupt the load current b
19、efore opening the disconnecting means for each power source. Where possible, visually verify that blades of disconnecting means are fully open and that drawout-type circuit breakers are fully withdrawn.Test conductors and equipment at both sources and equipment terminals for the presence of voltage.
20、 Use electrical testing equipment rated for the operating voltage of the system. Test the voltage sensing equipment on a known, energized source immediately before and after testing the equipment to be tested to ensure that the voltage sensing equipment is operating properly.Apply lockout/tagout dev
21、ices in accordance with a formal, written policy and in accordance with NFPA 70E-2012, Standard for Electrical Safety in the Workplace. Padlock and red tag all source switching devices in the open position. Remove locks and tags only after work is complete and tested, and all personnel are clear of
22、the area. Protect against accidental energization of automatic or remotely controlled equipment by identifying, opening, locking, and tagging starting devices. Open and lock or tag all load isolation devices to ensure that there are no loads connected to the equipment.Use Listed personal protective
23、grounds that are sufficient for the available short circuit current of the system. Connect personal protective grounds to the line terminals of the main circuit breaker or main lugs, to the neutral terminal bus bar, if so equipped, and to the grounding terminals of the equipment. Provide warning sig
24、ns at all primary disconnects indicating that the terminals are grounded. Do not remove the personal protective grounds until ready to test or energize conductors and equipment. Ground all possible sources of induced voltage and stored electric energy, such as conductors in close proximity to energi
25、zed parts and capacitors.Carefully inspect the work area and remove any tools and objects left inside before energizing conductors and equipment. Install all devices, panels, doors, and covers before energizing.n 61. Scope4.1 ReceivingUnload panelboards and components carefully, observing all packin
26、g label warnings and preventing damage to materials and components, or the loss of loose parts.Compare panelboards and accessories received with the bill of materials to verify that the shipment is complete. If the shipment is not complete, notify the manufacturer immediately in writing and note sho
27、rtages on the Bill of Materials.Verify that panelboards and accessories received conform to the manufacturers quotation and shop drawings and/or approved submittals. If they do not, notify the manufacturer immediately in writing.4.2 InspectionUnpack panelboards and components sufficiently to inspect
28、 for concealed damage resulting from shipping and handling.Inspect panelboards and components for damaged or displaced parts, for loose, cracked, broken, or chipped components, for damage to circuit breakers or switches, for dirt or foreign material, and for presence of water or moisture. Check “tip
29、” or “shock” indicators, if provided.If damage or contamination has occurred, notify the shipper and manufacturer immediately in writing. Do not proceed with installation until appropriate actions to clean or replace the panelboard have been taken.Repair or replace damaged components in accordance w
30、ith manufacturer instructions.If panelboards are to be stored prior to installation, restore original packing materials as much as possible, or cover with heavy plastic or canvas to protect panelboards from exposure to moisture, dust, dirt, and contaminants. When conditions permit, leave the packing
31、 materials intact until panelboards are ready for installation.4.3 HandlingHandle panelboards and accessories in accordance with manufacturer recommendations and instructions.Handle panelboards and accessories carefully to avoid damage to the cabinet, front cover, panelboard, frame, and components.
32、Avoid subjecting panelboards to impact, jolting, jarring, or rough handling.4.4 StorageProtect panelboards from dust, dirt, moisture, contamination, and physical damage. Cover with suitable temporary coverings to prevent deposits of dirt or other foreign material on movable parts and electrical cont
33、act surfaces.In locations with high humidity, remove panelboards from packing materials to permit adequate ventilation and to avoid mildew.Store panelboards in a clean, dry, heated building having a uniform temperature and adequate air circulation to prevent condensation.Where storage in a heated bu
34、ilding is not possible, store panelboards indoors in a clean, dry shelter having provisions for maintaining a uniform temperature and adequate air circulation to prevent condensation.4. Receiving, Inspecting, Handling and Storage7 nStandard for Installing and Maintaining Panelboards NECA 407Where it
35、 is not possible to store panelboards indoors, protect panelboards from weather and contaminants. Install electric heating to maintain a uniform temperature above ambient to prevent condensation, or make temporary power connections to equipment heaters, if so equipped. Ensure that all cartons and ot
36、her miscellaneous packing materials have been removed from panelboards before energizing any heaters. Where space heaters are supplied from auxiliary power transformers, take care to isolate low-voltage heater circuits before power-source connections to prevent inadvertent energizing of the auxiliar
37、y transformer and associated primary wiring.If panelboards are stored for extended periods of time, inspect the panelboard and spot check insulation resistance prior to installation (see Section 10.1). If any readings are low, dry out, clean, and /or replace components as necessary before placing pa
38、nelboards into operation. Consult the manufacturer for recommendations.n 81. Scope5.1 GeneralInstall panelboards in accordance with manufacturer recommendations, specific panelboard markings, and all installation instructions.Review manufacturer supplied shop drawings, arrangement drawings (front, e
39、nd, and plan view), connection diagrams, approved submittals, approved shop drawings, and equipment schedules before installation.Verify that supply overcurrent device(s) for panelboards and the panelboard feeders have a rating not greater than that of the panelboard and the panelboard feeder. Ensur
40、e that panelboard withstand ratings and circuit breaker interrupting ratings exceed the available fault current from the system as indicated by the short-circuit and coordination study provided by the owner, if available. Verify that series-rated panelboards meet the manufacturers Listing for series
41、-rating. Check that panelboards are tested and marked with testing combinations of the line-side overcurrent device and load-side circuit breaker(s) as required by NEC Article 240 for series-rated devices. Coordinate panelboard locations to ensure that the required minimum working space clearances a
42、re maintained in accordance with NEC Article 110. Ensure that the working space permits at least a 90-degree opening of equipment doors or hinged panels. Provide sufficient access to permit removing doors, covers, and panels for routine inspection, maintenance, and testing.Ensure that illumination i
43、s provided for panelboard working spaces in accordance with NEC Article 110.5.2 Environmental ConsiderationsVerify that panelboards and enclosures are suitable for the installation location. Generally, locate panelboards away from sources of water. Select panelboard enclosure types for use in specif
44、ic locations other than hazardous (classified) locations in accordance with NEC Article 110.Do not locate panelboards where exposed to ambient temperatures above 40C (104F), corrosive or explosive fumes, dust, vapors, dripping or standing water, abnormal vibration, mechanical shock, high humidity, o
45、r unusual operating conditions, unless the panelboard is designed and identified by the manufacturer for such conditions.Do not install panelboards in locations where the conditions would damage the equipment.5.3 Installation of CabinetsLocate cabinets so that they are readily accessible and not exp
46、osed to physical damage.Install cabinets level and plumb. Mount the cabinet securely to the mounting surface using manufacturer recommended methods, supports, and fasteners.Provide suitable guards or temporary covers on the cabinet after installation and prior to the permanent panelboard cover being
47、 installed to protect the cabinet from foreign substances such as paint, plaster, and acoustic spray.Close unused openings in panelboard enclosures using identified closures or other approved means that provide protection substantially equivalent to the wall of the enclosure as necessary to return t
48、he enclosure to the environmental rating required by the application.5. Installation9 nStandard for Installing and Maintaining Panelboards NECA 407In damp or wet locations, locate surface-mounted cabinets to prevent moisture or water from entering and accumulating within the cabinet. Provide a minim
49、um of 6 mm (1/4 in.) airspace between the cabinet and the wall or other supporting surface. Install weatherproof cabinets in wet locations. 5.3.1 Panelboard ClearancesFlush-Mounted Panelboards. Install cabinets with the front edge set back not more than 6 mm (1/4 in.) from the finished surface of walls constructed of non-combustible material such as concrete or tile. Install cabinets with the front edge flush with or projecting slightly beyond the finished surface of walls constructed of combustible materials such as wood.Allow a minimum of 1 m (3 ft) clearance between
