408.30 General
All panelboards shall have a rating not less than the minimum feeder capacity required for the load calculated in accordance with Article 220. Panelboards shall be durably marked by the manufacturer with the voltage and the current rating and the number of phases for which they are designed and with the manufacturer's name or trademark in such a manner so as to be visible after installation, without disturbing the interior parts or wiring.
FPN: See 110.22 for additional requirements.
Many panelboards are suitable for use as service equipment and are so marked by the manufacturer.
Listed panelboards are used with copper conductors, unless they are marked to indicate which terminals are suitable for use with aluminum conductors. Such marking must be independent of any marking on terminal connectors and must appear on a wiring diagram or other readily visible location. If all terminals are suitable for use with aluminum conductors as well as with copper conductors, the panelboard is marked ``Use Copper or Aluminum Wire.'' A panelboard using terminals or main or branch-circuit units individually marked AL-CU is marked ``Use Copper or Aluminum Wire'' or ``Use Copper Wire Only.'' The latter marking indicates that wiring space or other factors make the panelboard unsuitable for aluminum conductors. [See 110.14(C).]
Panelboards to which units (circuit breakers, switches, etc.) may be added in the field are marked with the name or trademark of the manufacturer and the catalog number or equivalent of those units intended for installation in the field.
Unless the panelboard is marked to indicate otherwise, the termination provisions are based on the use of 60?C ampacities for wire sizes 14 AWG through 1 AWG and 75?C ampacities for wire sizes 1/0 AWG and larger.
408.34 Classification of Panelboards
Panelboards shall be classified for the purposes of this article as either lighting and appliance branch-circuit panelboards or power panelboards, based on their content. A lighting and appliance branch circuit is a branch circuit that has a connection to the neutral of the panelboard and that has overcurrent protection of 30 amperes or less in one or more conductors.
(A) Lighting and Appliance Branch-Circuit Panelboard A lighting and appliance branch-circuit panelboard is one having more than 10 percent of its overcurrent devices protecting lighting and appliance branch circuits.
A lighting and appliance branch-circuit panelboard is one in which more than 10 percent of the installed overcurrent devices are rated 15, 20, or 30 amperes and supply circuits with a grounded (neutral) conductor. For example, a 24-position (space for 24 full-size circuit breakers), 120/240-volt, residential panelboard contains 21 overcurrent devices. If three or more (10 percent of 21 = 2.1) of those overcurrent devices supply 15-, 20-, or 30-ampere circuits with a neutral conductor, the panelboard is considered to be a lighting and appliance branch-circuit panelboard. However, if 12 two-pole, 30 ampere circuit breakers for electric heat are installed in the panelboard, there would be no branch circuits with neutral connections, and this panelboard therefore would be considered a power panelboard and subject to the overcurrent protection requirements of 408.36(B). If the supply circuit to this panelboard includes a neutral conductor, overcurrent protection not exceeding the rating of the panelboard is required on its supply side. This overcurrent protection can be located in the panelboard or, where supplied by a feeder, can be protected by the feeder overcurrent protective device.
(B) Power Panelboard A power panelboard is one having 10 percent or fewer of its overcurrent devices protecting lighting and appliance branch circuits.
A power panelboard is a panelboard that has 10 percent or less of the installed overcurrent devices supplying lighting and appliance branch circuits. Any panelboard that is not classified as a lighting and appliance branch-circuit panelboard is a power panelboard. A typical power panelboard could be located near the service and be designed to supply facility feeder circuits. The feeders from a power panelboard supply other utilization equipment or other panelboards that supply either other branch circuits or other feeders.
