March 17, 2014—The National Electrical Manufacturers Association (NEMA) recently published a white paper on molded case circuit breakers and two standards related to panelboards and deadfront distribution switchboards.
The white paper, NEMA ABP 4-2013 Taking the Guesswork Out of Selecting and Maintaining Molded Case Circuit Breakers, answers various questions related to the application and maintenance of circuit breakers. Updates include new references and links to other useful industry documents. The free publication was developed for users of electrical equipment in industrial and commercial applications. Use of this white paper can help reduce arc flash hazards, down-time due to systems failures, and other operations mishaps.
The ANSI/NEMA PB 1.1-2013 General Instructions for Proper Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less standard covers single panelboards or groups of panel units suitable for assembly in the form of single panelboards (including buses), with or without switches or automatic overload protective devices (fuses or circuit breakers), or both. These units are used in the distribution of electricity at 600 volts and less with: 1600 ampere mains or less, and 1200 ampere branch circuits or less.
The ANSI/NEMA PB 2.1-2013 General Instructions for Proper Handling, Installation, Operation, and Maintenance Deadfront Distribution Switchboards Rated 600 Volts or Less standard covers floor-mounted deadfront switchboards, which consist of an enclosure, molded case, and low-voltage power circuit breakers; fusible or non-fusible switches; instruments; and metering, monitoring, or control equipment with associated interconnections and supporting structures. These units are used in the distribution of electricity at: 600 volts and less, and 6000 amperes or less.
ANSI/NEMA PB 1.1 and ANSI/NEMA PB 2.1 may be downloaded at no cost or purchased in hardcopy format on the NEMA Web site for $40.
