1、NEMA Standards PublicationNational Electrical Manufacturers Associationg49g40g48g36g3g51g37g3g20g16g21g19g20g20g3g51g68g81g72g79g69g82g68g85g71g86NEMA Standards Publication PB 1-2011 PanelboardsPublished by: National Electrical Manufacturers Association1300 North 17th Street, Suite 1752 Rosslyn, Vir
2、ginia 22209 www.nema.org Copyright 2011 by the National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pa
3、n American Copyright Conventions. NOTICE AND DISCLAIMERThe information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the document at the time it was developed. Consensus does not necessarily mean that there is unanimous ag
4、reement among every person participating in the development of this document. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus standards development process. This
5、process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the document and it does not indepen
6、dently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect,
7、consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, express or implied, as to the accuracy or completeness of any information published herein, and disclaims and ma
8、kes no warranty that the information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers products or services by virtue of this standard or guide. In publishing and making this document
9、 available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as approp
10、riate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or infor
11、mation not covered by this publication. NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of comp
12、liance with any health or safetyrelated information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. PB 1-2011 Page i Copyright 2011 by the National Electrical Manufacturers Association CONTENTSPageSection 1g3 GENERAL . 1
13、g31.1g3 Scope. 1g31.2g3 Referenced standards . 1g31.3g3 Definitions 2g3Section 2g3 PANELBOARDS . 10g32.1g3 Types of Panelboards 10g32.2g3 Lighting and Appliance Branch-Circuit Panelboards . 10g32.3g3 Distribution Panelboards . 11g32.4g3 Panelboard Circuit Protective Devices, NEMA Standards 12g32.5g3
14、 UL Requirements . 12g32.6g3 Usual Service Conditions 12g32.7g3 Unusual Service Conditions 12g32.8g3 Suitability for Use as Service Equipment 12g32.8.1g3 Ground-Fault Protection 13g32.9g3 Lighting and Appliance Branch-Circuit Panelboard Mains 13g32.10g3 Standard Main Bus, Switch, and Breaker Ratings
15、 13g32.11g3 Product Safety Labels . 13g3Section 3g3 RATING STANDARDS . 15g33.1g3 Standard Voltage Rating . 15g33.2g3 Current Rating . 15g33.2.1g3 Panelboards Using a Snap Switch 15g33.3g3 Frequency Rating 15g33.4g3 Basis of Short-Circuit Current Rating of Panelboards . 16g33.5g3 Standard Short-Circu
16、it Current Ratings of Panelboard Devices . 16g33.5.1g3 Circuit Breakers . 16g33.5.2g3 Fusible Switches 16g33.5.3g3 Other Devices 16g3Section 4g3 INSTALLATION, MAINTENANCE, AND STORAGE . 17g3Section 5g3 CONSTRUCTION 18g35.1g3 General 18g35.1.1g3 Marking Information . 18g35.1.2g3 Other Markings 18g35.
17、2g3 Uninsulated Live Metal Parts . 18g35.3g3 Wiring Terminations . 18g35.3.1g3 Conductor Terminals . 18g35.3.2g3 Main Terminals Kits . 18g35.3.3g3 Main and Branch-Circuit Terminals. 19g35.3.4g3 Connectors 19g35.4g3 Spacings 19g35.4.1g3 Minimum Panelboard Spacings . 19g35.4.2g3 Insulating Material Ot
18、her than Air 20g35.4.3g3 Screw Shells 20g35.4.4g3 Wire Connectors (Lugs) 20g35.5g3 Grounding and Insulating 20g35.5.1g3 Operating Handle 20g35.5.2g3 Grounding and Bonding 20g35.5.3g3 Size of Grounding Conductors 20g35.5.4g3 Equipment Grounding Terminals . 21g35.5.5g3 Size of Grounding Electrode Cond
19、uctors and Main Bonding Jumper 21g35.5.6g3 Grounding of Three-Phase Delta Systems . 21g35.6g3 Cabinets, Gutters and Wiring Space. 22g3PB 1-2011 Page ii Copyright 2011 by the National Electrical Manufacturers Association 5.6.1g3 Cabinet 22g35.6.2g3 Distance between End of Wiring Lugs and Opposite Wal
20、l 22g35.6.3g3 Enclosed Panelboard 22g35.6.4g3 Knockouts 22g35.6.5g3 Wiring Gutters and Terminal Compartments . 22g35.6.6g3 Wiring Space . 22g35.7g3 Fuse and Circuit Breaker Location 22g35.7.1g3 Fuse . 22g35.7.2g3 Circuit Breakers with Interchangeable Trip Units 22g35.8g3 Enclosures . 22g35.8.1g3 Typ
21、es of Enclosures 23g3Section 6g3 TEST STANDARDS 24g36.1g3 Classification of Tests 24g36.1.1g3 Design Tests (Type Test) 24g36.1.2g3 Production Tests (Routine Test) 24g36.2g3 Design Tests (Type Test) 24g36.2.1g3 Temperature Rise Tests 24g36.2.2g3 Dielectric Tests 24g36.2.3g3 Short-Circuit Tests . 25g3
22、6.2.4g3 Environmental Tests 25g36.2.5g3 Strength of Insulating Base and Support Test 25g36.3g3 Production Tests (Routine Test) 25g36.3.1g3 Ground-Fault-Sensing Test . 25g3Section 7g3 APPLICATION STANDARDS 26g37.1g3 Selection of Apparatus 26g37.2g3 Voltage Ratings . 26g37.3g3 Continuous-Current-Carry
23、ing Ratings . 26g37.3.1g3 Panelboard without Main Overcurrent Protective Devices (Main Lug Panelboard) 26g37.3.2g3 Panelboard Having One or More Main Overcurrent Protective Devices 26g37.3.3g3 Branch-Circuit Devices 26g37.3.4g3 Panelboards with Feed-Through or Sub-Feed Lugs . 26g37.4g3 Calculation o
24、f Available Short-Circuit Current . 26g37.5g3 Short-Circuit Current Ratings 26g37.5.1g3 Panelboard Short-Circuit Current Rating 26g37.5.2g3 Examples for Application . 26g37.6g3 Field-Installed Conductors . 28g37.7g3 Corner-Grounded (Grounded B Phase) Three-Phase Delta Applications 28g37.8g3 Mounting
25、 of Enclosure . 28g3LIST OF TABLES Table 2-1 Standard Lighting and Appliance Branch-Circuit Panelboard Voltage Systems 10 Table 2-2 Standard Distribution Panelboard Voltage Systems . 11Table 2-3 Usual Ambient Limits of Devices Commonly Mounted in Panelboards . 12 Table 3-1 Standard Panelboard Voltag
26、e Ratings 15 Table 5-1 Minimum Panelboard Spacing, Inch (mm) 20Table 5-2 Size of Grounding Electrode Conductors and Main Bonding Jumper 21 PB 1-2011 Page iii Copyright 2011 by the National Electrical Manufacturers Association LIST OF FIGURES Figure 1-1 Double-Lugs or Sub-feed Lugs Connected to Main
27、Incoming Line Terminals. 4 Figure 1-2 Sub-feed Lugs Connected to Bus Bars Protected by an Overcurrent Protective Device in the Panelboard . 5 Figure 1-3 Feed-Through Lugs for a Separate Circuit External to the Panelboard . 5 Figure 1-4 Gutter Tap Lugs Connected to Panelboard Mains 7 Figure 1-5 Gutte
28、r Tap Lugs Connected to a Branch Circuit . 7Figure 2-1 Product Safety Label 14 Figure 7-1 Typical Panelboard Schematic . 27 PB 1-2011 Page iv Copyright 2011 by the National Electrical Manufacturers Association FOREWORDThis standards publication is intended to provide a basis of common understanding
29、within the electrical community by aiding the user and specifier in properly selecting panelboards for specific applications by stating:a. The general standards for panelboards including the types, insulating requirements, unusual service conditions, service equipment requirements, ampacity, and mar
30、kings b. Standard panelboard ratings including short circuit current ratings c. Test procedures and tests for panelboard design and production d. Manufacturing standards for panelboards e. Panelboard application standards to provide proper selection of a panelboard and its components to ensure satis
31、factory service PB 1-2011 completely revises and supersedes PB 1- 2006. These standards are periodically reviewed by the Panelboard and Distribution Board Section of NEMA for any revisions necessary to keep them up-to-date with advancing technology. User needs have been considered throughout the dev
32、elopment of this publication. Proposed or recommended revisions should be submitted to: Vice President, Technical Services National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 This standards publication was developed by the Panelboard and Distribut
33、ion Board Section. At the time it was approved, the section was composed of the following members: ABB, Inc.New Berlin, WI Cooper BussmannSt. Louis, MO Eaton CorporationPittsburgh, PA The Durham CompanyLebanon, MO GE Industrial SolutionsPlainville, CT Hubbell, Inc.Bridgeport, CT Penn Panel test link
34、: A current-carrying part made of copper and having dimensions such that it will fit its fuse mounting means with the same conditions of pressure, contact, and cross-sectional areas as are obtained on terminals of the fuse that it is intended to replace. A dummy fuse is not a protective device and i
35、s intended for use only in design tests. enclosed panelboard: A panelboard that is mounted in a suitable cabinet or enclosure. enclosure: A surrounding case constructed to provide a degree of protection to personnel against incidental contact with the enclosed equipment and to provide a degree of pr
36、otection to the enclosed equipment against specified environmental conditions. feed-through lugs: Terminals that are connected to the main bus bars at the end opposite from the incoming line terminals and that provide for connection to outgoing cables (see Figure 1-3).Figure 1-1DOUBLE-LUGS OR SUB-FE
37、ED LUGS CONNECTED TO MAIN INCOMING LINE TERMINALS PB 1-2011 Page 5 Copyright 2011 by the National Electrical Manufacturers Association Figure 1-2 SUB-FEED LUGS CONNECTED TO BUS BARS PROTECTED BY ANOVERCURRENT PROTECTIVE DEVICE IN THE PANELBOARD Figure 1-3 FEED-THROUGH LUGS FOR A SEPARATE CIRCUIT EXT
38、ERNAL TO THE PANELBOARD PB 1-2011 Page 6 Copyright 2011 by the National Electrical Manufacturers Association flush mounted (type): A device designed to be set into and secured to a flat surface, with a minimal front projection.frame size: Applies to a group of molded case circuit breakers that are p
39、hysically interchangeable with each other. Frame size is expressed in amperes and corresponds to the largest ampere rating available in the group. Groups may or may not be physically interchangeable with each other whether furnished by one manufacturer or various manufacturers. fuse: A protective de
40、vice that opens by the melting of a current-sensitive element during specified overcurrent conditions.fuse clips: The contacts of the fuseholder that support the fuse and connect the fuse terminals with the circuit. fusible switch: A switch in which one or more poles have a fuse in series in a compo
41、site unit. fuseholder: An assembly of a base, fuse clips, and necessary insulation for the mounting and connecting of a fuse into a circuit. grounded: Connected to earth or to some conducting body that serves in place of the earth. grounded conductor: A system or circuit conductor that is intentiona
42、lly grounded. ground-fault protector (GFP): A ground-fault protector is a device or system that provides protection for equipment (not for personnel) by opening the circuit in case of a predetermined ground-fault current. A ground-fault protector includes a ground-fault current sensing device and re
43、laying equipment, or a combination of a ground-fault current sensing device and relaying equipment, that will operate to cause a disconnecting means to function at a predetermined value of ground-fault current. grounding conductor: A conductor used to connect equipment or the grounded circuit of a w
44、iring system to the grounding electrode or electrodes. grounding conductor, equipment: The conductor used to connect noncurrent-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or
45、at the source of a separately derived system. gutter tap lugs: Terminals that are located in a wiring gutter of a panelboard cabinet and that provide for (1) the connection of the incoming and outgoing conductors and panelboard mains, or (2) the connection of two sets of outgoing conductors to a bra
46、nch or other outgoing circuit (see Figure 1-4 and Figure 1-5).PB 1-2011 Page 7 Copyright 2011 by the National Electrical Manufacturers Association Figure 1-4 GUTTER TAP LUGS CONNECTED TO PANELBOARD MAINS Figure 1-5 GUTTER TAP LUGS CONNECTED TO A BRANCH CIRCUIT PB 1-2011 Page 8 Copyright 2011 by the
47、National Electrical Manufacturers Association hinged-cover switch: A switch that disconnects the circuit when the hinged cover is manually operated and in which suitable means are provided for reclosing the cover without reestablishing the circuit. interlock: An electrical or mechanical component ac
48、tuated by the operation of a device or other means with which it is directly associated to govern succeeding operations of the same or allied devices. interrupting rating: The highest current at rated voltage that a device is intended to interrupt under standard test conditions. knockout: A portion
49、of the wall of a box or enclosure that may be removed readily at the time of installation in order to provide an unthreaded hole for the attachment of raceway, cable assemblies, or their fitting. lighting and appliance branch circuit panelboard (This definition applies to equipment intended for use with the editions of the National Electrical Code 1999 through 2005): A panelboard having more than 10 percent of its overcurrent devices rated 30 amperes or less, for which neutral connections are provided. Not more than forty-two overcurrent devices (other than those provi
