220.12 Lighting Load for Specified Occupancies.
Code Change Summary: A new exception was added to 220.12 to allow lighting load calculations to be determined in accordance with locally adopted energy codes.
Table 220.12 has been used for many code cycles when performing load calculations. This table provides general lighting load values in volt-amps (VA) per square foot based on the different occupancy types.
A new exception allows the use of an alternate method to calculate the general lighting load for a building as long as it is done in compliance with an energy code adopted by the local authority. In order to apply the new exception, three conditions must be met:
- There must be a power monitoring system installed that provides continuous information regarding the total general lighting load of the building.
- The power monitoring system must have an alarm to alert the building owner or manager if the lighting load exceeds the values required by the energy code.
- The demand factors in 220.42 cannot be applied to the general lighting load.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).
2014 Code Language:
220.12 Lighting Load for Specified Occupancies. A unit load of not less than that specified in Table 220.12 for occupancies specified therein shall constitute the minimum lighting load. The floor area for each floor shall be calculated from the outside dimensions of the building, dwelling unit, or other area involved. For dwelling units, the calculated floor area shall not include open porches, garages, or unused or unfinished spaces not adaptable for future use.
Informational Note: The unit values herein are based on minimum load conditions and 100 percent power factor and may not provide sufficient capacity for the installation contemplated.
Exception: Where the building is designed and constructed to comply with an energy code adopted by the local authority, the lighting load shall be permitted to be calculated at the values specified in the energy code where the following conditions are met:
(1) A power monitoring system is installed that will provide continuous information regarding the total general lighting load of the building.
(2) The power monitoring system will be set with alarm values to alert the building owner or manager if the lighting load exceeds the values set by the energy code.
(3) The demand factors specified in 220.42 are not applied to the general lighting load.