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Tuesday, February 14, 2017
Question:
My questions are for grounding luminaires on top of metal light poles. Are you required to run an EGC up the pole to the luminaire to ground it per part V of Article 410? I would think a luminaire on top of a metal light pole, such as in a parking lot, would not need an EGC run to the luminaire at the top because the luminaire is inaccessible to unqualified persons per 410.42. Also, what are your thoughts about the metal light pole being used as an EGC? Would it make a difference if the pole was listed or not? As always, looking forward to your answers as a warm up to start my days.
Conrad L.
A
Answer:
Hey Conrad thanks for your question and the kind words. Poles are allowed to support luminaires and be used as raceways for those conductors under the conditions provided as stated in 410.30(B). Metal poles must be provided with an equipment grounding terminal as stated in 410.30(B)(3) and the equipment grounding conductor must be connected as stated in 410.30(B)(5). The metal poles are not specifically referred to as equipment grounding conductors but they function as one. Luminaires must be grounded by Article 250 and Part V of Article 410 as stated in 410.40.
Normally non-current carrying metal parts of equipment, likely to become energized, must be connected to an equipment grounding conductor, under any of the conditions included as stated in 250.110. Pole supported luminaires would be in a wet location [250.110(2)], would probably be in electrical contact with the metal pole [250.110(3)], and would be supplied by a wiring method that provides an equipment grounding conductor [250.110(5)]. So far the rules are fairly clear.
Exposed metal parts of luminaires must be connected to an equipment grounding conductor, or be insulated from the equipment grounding conductor, or inaccessible to unqualified personnel as stated in 410.42. Notice the wording is not limited to specific types of luminaires nor does it give guidance as to what" inaccessible to qualified personnel" means, so an AHJ could apply that concept.
Luminaries must be provided with a means for connecting an equipment grounding conductor as stated in 410.46 and be listed as stated in 410.6 so any instruction included with that listing applies as stated in 110.3(B). Looking at all the rules collectively it seems that connecting the equipment grounding conductor to the luminaire would be prudent. Consider submitting a Public Input to 410.42 for the 2020 NEC by September 7 of this year to improve the wording.