Calculating Fluorescent Lights in a Shop

All lighting requirements and lighting loads fall under the regulations of the National Electrical Code or simply known as NEC. Volt-amperes are the same calculation as wattage. All lights, which also include fluorescents, have ratings in wattage that is specified on the fixture. The wattage rating is supposed to be equal to the fixture’s overall light output. Here are the guides on how to calculate the fluorescent lights in a shop.

Things that you need:

  • A Shop
  • Fluorescent Lights

Fluorescent Lights


  • Measure the outside of the shop building’s width and length. These measurements must be the exact exterior measurements of that particular building.
  • To get the shop’s overall square footage, multiply the length times with the width. Moving on, you should then calculate the required amount of lighting in wattage by multiplying the overall square footage times 2 watts. For example, a shop of 1,000 square feet will require about 2,000 watts of lighting.
  • You should then divide the individual fluorescent light fixture rating by the overall requirement in the previous step. Another example, the usual 4 foot two-bulb fluorescent light fixture has an average wattage output of 80 watts.
  • You can divide 2000 watts by 80 watts to get the result of the 4 foot two bulb fixtures, which is equal to 25 fixtures spaced evenly throughout the shop.
  • If your local regulations may not be the same as stated in the NEC, consult with your local electrical regulating agency.

Image Credit:

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Additional Reading:

Fluorescent Light and Its Applications

Black & Decker Wiring 101: 25 Projects You Really Can Do Yourself (Black & Decker 101)