Sizing conductor and OCPD to Industrial Equipment Nameplate

[jes25]

Often we get a request to connect a machine. A customer is usually adding or changing some industrial equipment. I have a picture of a nameplate from a recent request for example. Typically, if the machine doesn't have a main OCPD integrated into it, we would look at the nameplate, consider it ALL to be continuous load (who knows if it continuous), apply the 125% factor and select the conductor and OCPD accordingly.

Then I started thinking about 240.3 and providing OCPD for the equipment itself. Considering the nameplate I have attached is there a maximum OCPD for the equipment? Is it possible to oversize the OCPD from a protection to the equipment point of view? Do you agree just taking the nameplate by 125% provides a complaint install even if a little oversized?

I would say the nameplate in question is not an "appliance" or "industrial machine" per the NEC.

 

[EngineeredElectric]

If it's not an industrial machine then what is it? There may be another article of code that covers this piece of equipment.

The NEC definition for a continuous load is "A load where the maximum current is expected to continue for 3 hours or more".

I cannot think of a single piece of industrial equipment that I have ever interacted with that I would expect to operate at maximum current nonstop for 3 hours. Certainly it exists in theory, and I'm sure there are real world examples, but all in all I think it's fair to say that is pretty rare.

As far as this specific machine goes, there will have to be more information about the equipment itself to decide which articles apply and which ones do not.