National Electrical Code Top Ten Tips: Article 600, Electric Signs and Outline Lighting
- 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.
- 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.
- 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)].
- 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)].
- 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.
- Each installed system must have a disconnect that opens all ungrounded
conductors and controls no other load [600.6].
- 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.
While 600.7(A) provides the requirements for bonding the signs, 600.7(B) provides requirements for bonding everything else.
- 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....
- 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.