The Electrical Code

220.12 Lighting Load for Specified Occupancies. Lighting is an unusual calculation. The calculation depending on what type of environment your in and the square footage is a must because as night falls on the winter it come quicker then any other time of the year and this is when you need the most lighting. It sucks to come into a dark room that can’t be made brighter because of a poor lighting plan. There are electrical engineers that take on the task of being experts on lighting and control panels for lighting. Because it’s just as important to have light and know when it should be turned off or dimming a light or two makes the area feel better depending on the situation.

To accompany this article comes energy efficiency. LED’s have made the world of lighting so much better that as electricians lighting might become a job all it own if this is not already something companies specialize in. I can’t see a company just doing lighting but you never know how busy they get and hold there staff when times are slow. I know I was let go early a bunch of times in the beginning of my career because the shop I worked for was slow. But as soon as it picked up things changed around and I was back to work after a small vacation.

“A unit load of not less than that specified in Table 220.12 for occupancies specified 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 are based on minimum load conditions and 100 percent power factor and may not provide sufficient capacity for the installation contemplated.

Exception No. 1: 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.

Exception No. 2: Where a building is designed and constructed to comply with an energy code adopted by the local authority and specify‐ ing an overall lighting density of less than 13.5 volt-amperes/13.5 m2 (1.2 volt-amperes/1.2 ft2), the unit lighting loads in Table 220.12 for office and bank areas within the building shall be permitted to be reduced by 11 volt-amperes/11 m2 (1 volt-amperes/1 ft2).”