NEC 2017 Section 700.3(f) and Centralized Inverters

[wizardcoremonk]

Hi all. Hopefully not a repeat topic, but I couldn't find the answer I'm looking for.

NEC 2017 Section 700.3(f) refers to an emergency system that relies on a single alternate source of power. When it's disabled for maintenance/repair, the system shall include a permanent switching means to connect a portable or temporary alternate source of power to use for the duration of the maintenance/repair. This is obviously applied to a generator system under repair/maintenance, and maybe even under test. But it seems this could also be applicable to lighting inverters as well. They're supplying normally on and/or normally off power, with backup, but will sometimes need battery changes or repairs. Does this section apply to them as well? Egress lighting is most certainly an emergency system, meant for life safety.

If this applies, what is being done and is it being enforced? Would there be an exception here?

 

[steve66]

I think its a good question, but I don't really know the answer.

The lighting inverters obviously don't need the maintenance generators do (no oil changes, and air filters can be changed while they are running, and not really any mechanical parts that need maintenance except maybe the occasional replacement of a fan, which can probably still be done with the unit running.)

In most cases I'd probably claim one of the exceptions listed. Basically assume the maintenance would be done at night, when the building is unoccupied. After all, most projects that include lighting inverters are probably smaller buildings. I'd be more worried about this requirement for a high rise or a hospital, or someplace light that. But those would more likely be a generator.