Skip navigation

Outside Branch Circuits and Feeders, Part 2

How many different applications of outdoor lighting does your facility have? Security, walkways, parking lots, entry, flagpole, and landscaping are common applications. All of these must comply with Art. 210, and with these requirements from Sec. 225.7:

  • The ampacity of the neutral conductor must be at least equal to the net calculated load between the neutral conductor and all ungrounded conductors connected to any one phase
  • You can supply the luminaires at no more than 277V
  • You can supply the auxiliary equipment of electric-discharge lamps at no more than 600V

In the past, these limits sometimes made it challenging to get sufficient light without excess voltage drop when lighting a large area such as a campus. Simply running oversized conductors might not be practical or even enough of a solution. You might have to think in terms of 480V distribution and stepdown transformers, with all the attendant installation costs, security concerns, and maintenance issues.

Technology has changed this game. Today you have many good choices in attractive outdoor LED lighting. Their significantly lower power draw makes it much easier to design a Code-compliant outdoor lighting system with less infrastructure. You may further reduce design challenges by using solar-powered units, rather than wired, as part of your outdoor lighting mix.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.