The National Electrical Manufacturers Association (NEMA) published  ANSI/NEMA PB 1.1-2013 General Instructions for Proper Handling, Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less and ANSI/NEMA PB 2.1-2013 General Instructions for Proper Handling, Installation, Operation, and Maintenance Deadfront Distribution Switchboards Rated 600 Volts or Less.

ANSI/NEMA PB 1.1-2013 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 600V and less with:

  • 1,600A mains or less
  • 1,200A branch circuits or less

ANSI/NEMA PB 1.1 may be downloaded at no cost or purchased in hard copy format on the NEMA website for $40.

ANSI/NEMA PB 2.1 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:

  • 600V and less
  • 6,000A or less

ANSI/NEMA PB 2.1 may be downloaded at no cost or purchased in hardcopy format on the NEMA website for $40.