UFC 3 -520-01
June 10, 2002
5-5.7.1.4 Lighting and appliance branc h circuit panelboards--rated for up to about 225
amperes at 600 volts or less, although exceptions to this general rule are common.
Individual disconnect devices are often rated for 30 amperes or less. Lighting and
appliance branch circuit panelboards are limited by NEC Article 408.15 (2002 Edition) to
contain not more than 42 overcurrent devices (other than those provided for in the
mains) in any one cabinet or cutout box.
Note: For purposes of NEC classification, panelboards are classified as either
po wer panelboards or lighting and appliance branch circuit panelboards. A
power panelboard is one having 10 percent or fewer of its overcurrent devices
protecting lighting and appliance branch circuits.
5-5.7.2 Select distribution panelboards of the wall -mounted, dead-front type, either
circuit breaker or fusible switch equipped with copper bus . Branch circuit panelboards
should be of the wall-mounted, dead-front type, equipped with circuit breakers. Circuit
breaker size should be a minimum 25 millimeters (1 inch) per pole with bolt -on
breakers. Load center panelboards should be used only where eight or fewer circuits
are supplied, and where light duty can be expected, except as authorized for military
family housing. Although such use is usually discouraged, panelboards other than the
dead-front externally-operable type are permitted where accessible only to qualified
persons.
5-5.7.3 Provide overcurrent protection of panelboards in accordance with NEC Article
408.16 (2002 Edition) as follows.
5-5.7.3.1 Protect each lighting and appliance branch circuit panelboard on the supply
side by not more than two main circuit breakers or two sets of fuses having a combined
rating not greater than that of the panelboard. The preferred configuration is to supply a
main disconnect breaker on each panelboard.
5-5.7.3.2 Protect power panelboards with supply conductors that include a neutral and
having more than 10 percent of its overcurrent devices protecting branch circuits rated
30 amperes or less on the supply side by an overcurrent protective device having a
rating not greater than that of the panelboard.
5-5.7.3.3 Provide overcurrent protection not in excess of 200 amperes for panelboards
equipped with snap switches rated at 30 amperes or less.
5-5.7.3.4 The total load on any overcurrent device located in a panelboard must not
exceed 80 percent of its rating where, in normal operation, the load will continue for
three hours or more unless the overcurrent device is listed for continuous operation at
100 percent of its rating.
5-5.7.3.5 Where a panelboard is supplied through a transformer, provide the
overcurrent protection on the secondary side of the transformer.
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