You are referring to the demand factor calculation for continuous loads. Here's a breakdown of where to find the relevant information in the 2017 NEC, why it's there, and what "etc." likely means in your context

1. Where to Find the 125% Rule (and the confusion around it)

The 125% rule applies to continuous loads. This is not about specific occupancies like banks or restaurants directly. The confusion arises because certain occupancies tend to have a higher proportion of continuous loads. The key is understanding what constitutes a continuous load. NEC Article 100 (Definitions)



Continuous Load

A load where the maximum current is expected to continue for 3 hours or more.

NEC 210.20(A)

Specifically states that a branch circuit supplying continuous loads shall have an ampere rating not less than 125 percent of the continuous load. This is a circuit-level requirement.

NEC 215.3

Feeders. Feeder conductors shall have an ampacity not less than required to supply the load as determined by Parts III, IV, and V of this article. The minimum feeder circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity equal to or greater than the noncontinuous load plus 125 percent of the continuous load.

NEC 220.18(A)

General. The feeder or service load for a dwelling unit shall be determined in accordance with 220.18(B) through (E). The calculated load shall not be less than 100 percent of the noncontinuous loads plus 125 percent of the continuous loads.

2. Why the 125% Rule? Safety and Conductor Heating

Conductors heat up when carrying current. Continuous loads, by definition, cause prolonged heating. The 125% factor helps ensure that conductors and overcurrent protection devices (circuit breakers/fuses) aren't continuously operating at their maximum rated capacity, which can lead to premature failure, nuisance tripping, and potentially fire hazards.

3. Is it for ALL Commercial Locations? No. The 125% rule applies to any feeder/service (including commercial, industrial, or residential) that has a continuous load. If a commercial space has predominantly non-continuous loads, you wouldn't necessarily apply the 125% factor to the entire calculated load. You'd apply it only to the continuous portion.4. Occupancies and the Likelihood of Continuous Loads

Occupancies like banks, restaurants, and office buildings are more likely to have significant continuous loads. Think about:

Banks

Computers, servers, lighting, HVAC equipment all potentially running for extended periods.

Restaurants

Refrigeration, cooking equipment, some lighting, point-of-sale systems.

Office Buildings

Lighting, computers, HVAC, and potentially other office equipment.This doesn't mean every bank or restaurant automatically gets the 125% applied to its total load. You still need to assess what is actually a continuous load.

5. What Does "Etc." Mean?"Etc." in the document you're referencing is vague and unacceptable for code interpretation. It means "and so forth." A professional electrical engineer or contractor should never rely on such ambiguous wording. You must determine what is actually a continuous load according to the NEC definition, regardless of the occupancy.6. How to Apply the Rule (Key Steps)


Identify Loads

List all loads that will be connected to the feeder or service.2.

Determine Continuous vs. Non-Continuous

For each load, decide if it's continuous (expected to operate at maximum current for 3 hours or more).3.

Calculate Continuous Load

Sum the total kVA (or VA) of all continuous loads.4.

Calculate Non-Continuous Load

Sum the total kVA (or VA) of all non-continuous loads.5.

Apply the 125% Factor

Multiply the total continuous kVA/VA by 1.25 (or 125%).
6.

Add the Results

Add the result from step 5 (125% of continuous load) to the non-continuous load from step 4. This is the minimum required feeder/service capacity.

Example

Let's say a small office has:

Continuous Loads

Lighting: 5 kVA Computers/Servers: 3 kVA Total Continuous Load: 8 kVA

Non-Continuous Loads

Printer: 1 kVA Occasional Space Heater: 2 kVA Total Non-Continuous Load: 3 kVACalculations: 125% of Continuous Load: 8 kVA 1.25 = 10 kVA Total Required Feeder/Service Capacity: 10 kVA + 3 kVA = 13 kVA

Important Considerations for Arizona (and all locations)



Local Amendments

Always check with your local jurisdiction (city or county) in Arizona to see if they have adopted any amendments to the 2017 NEC. Local amendments can modify or add to the NEC requirements.

Engineering Judgment

Electrical design always involves a degree of professional judgment. Consider future load growth when sizing feeders and services. It's often better to slightly oversize than to undersize.

Documentation

Keep detailed documentation of your load calculations. This is important for inspections and for future reference.

Recommendation:

Consult with a licensed electrical engineer or qualified electrical contractor in Arizona for assistance with your specific project. They can ensure that your electrical design meets all applicable code requirements and is safe and reliable. Don't rely on vague wording like "etc." in your design. Flag for review