Neon Signs and Lighting, Part 3

Neon Signs and Lighting, Part 3In Part 2, we began looking at requirements for neon installations that operate over 1kV. All conductors for these systems must be [600.32(B)]:

  • Insulated.
  • Listed as gas tube sign and ignition cable GTO.
  • Rated for 5, 10, or 15 kV (depending upon your system voltage).
  • At least 18AWG.
  • Have a minimum temperature rating of 221 DegrF.

Compare that to the conductor requirements for systems 1kV or less [600.31(B)]:

  • Insulated.
  • Listed.
  • At least 18AWG.

The next requirement we find in 600.32 is to install the conductors so they aren’t subject to physical damage. This requirement also appears in many other Articles. But it really does not need to be stated, because:

  • Failing to consider this common sense requirement constitutes negligence.
  • The requirement is explicitly stated in 300.4, and thus applies to all circuits and types of installations.
  • The requirement is implicit in the NEC. Among other things, it logically follows from the NEC’s wiring method requirements (e.g., permitted and not permitted uses).

The NEC doesn’t define “subject to physical damage,” but we know it when we see it. You need to ensure that the wiring method can withstand the conditions of use [Annex D, Example D3(a)]. We already make temperature adjustments. Adjusting for possible physical damage is just another step you must take.

For example, there’s a driveway between the sign and the power source. To protect the conductors, you might trench under the driveway.

« Part 2 | Part 4 » | Source: Mark Lamendola | Mindconnection

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