Based on the 2020 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 600, Electric Signs and Outline Lighting

  1. While Chapter 5 is arranged thematically, Chapter 6 is not. Therefore, you don't have the equivalent of Article 500 that lays the basis for several other Articles. Instead, Chapter 6 just starts off with a fairly arcane topic.
     
  2. Article 600 covers the installation of electric signs and outline lighting [600.1], regardless of voltage. Don't confuse outline lighting with outdoor lighting, though outline lighting may be outdoors.
     
  3. You'll find the definition of skeleton lighting in 600.2. While normally any electrical equipment you install must be listed for that particular use, the listing requirement does not apply to skeleton lighting when field-installed per Article 600 requirements [600.3(A)].
     
  4. If outline lighting consists of listed luminaires and you install it per Chapter 3 requirements, it's redundant to have the outline lighting assembly itself listed. So, listing isn't required [600.3(B)].
     
  5. When you calculate branch circuit sizing for the systems, you must consider them to be continuous loads [600.5(C)]. That does not preclude diversity calculations, but if doing those keep in mind the hours of operation.
     
  6. Each installed system must have a disconnect that opens all ungrounded conductors and controls no other load [600.6].
     
  7. Article 600 uses the word "grounding" incorrectly (see Article 100 for definition, see Part V of Article 250 for more info). Do not ground these lighting circuits. The intent here is that you bond them. When reading 600.7(A), just substitute "bond" for "ground" and follow the requirements. The reason for the language misuse is we are still incorrectly referring to equipment bonding conductors as equipment grounding conductors. The idea here is that 600.7(A) applies to the bonding connections. Don't connect the green wire to a ground rod or to building steel; connect it to the equipment "grounding" (bonding) conductor.
     
  8. While 600.7(A) provides the requirements for bonding the signs, 600.7(B) provides requirements for bonding everything else.
     
  9. Just as people often confuse temporary power with "lax requirements," they often have that same confusion with portable and mobile signs. Note that these do require adequate support [600.10(A)] and must meet the other requirements of 600.10. Apply common sense is generous serving sizes....
     
  10. The requirements for LED lighting are new with the 2011 NEC, and you will find them in 600.33. This does not refer to LED per se, but LED systems are Class 2.