You're asking a really important question about NEC requirements for a commercial plaza electrical upgrade. Here's a breakdown of the situation and the applicable NEC sections, considering both perspectives

Arguments for Requiring a Load Summary:
NEC 220.5(A): General. This section is broad but fundamentally important. It states that branch-circuit, feeder, and service calculations shall be performed as specified in Article 220. This lays the groundwork for the entire article being applicable. NEC 220.87: Determining Existing Loads. This section, while specifically talking about existing loads, provides a method for determining loads. Your engineer is correct that the exact application of this section isn't for a new service. However, the PRINCIPLE of analyzing existing usage to size new infrastructure is absolutely critical, and this section is the closest the NEC comes to requiring it. The code doesn't assume that just because a service is new, the load calculations are simple. You have to account for the actual expected load. NEC 220.80: Noncoincident Loads. This section talks about the ability to take into consideration non-coincident loads when determining the feeder or service-entrance conductor size. This is relevant because the stores in the plaza may have different peak load times. Practical Considerations & Due Diligence

Even if the letter of the code doesn't explicitly mandate a detailed load summary, responsible engineering practice demands it. You cannot size a new service entrance adequately without understanding the aggregate load requirements of the tenants. It's an ethical and professional obligation to ensure the new service is sized appropriately. Undersizing is a huge problem with major liability.

Arguments Against Requiring a "Formal" Load Summary (Engineer's Perspective)



Tenant Responsibility

The engineer might argue that each individual tenant is responsible for ensuring their load doesn't exceed the capacity allotted to them. This is true to a point. Each tenant is responsible for their individual loads.



New Service Focus

The engineer might focus solely on designing the new main switchboard based on the total available capacity and providing adequate distribution to the tenants. They might argue they're providing the "infrastructure" and the individual tenants are responsible for connecting to it within their allocated limits.

Prescriptive vs. Performance-Based Design

The NEC is a prescriptive code (it tells you how to do things). It doesn't explicitly require a formalized "load summary" for new commercial service upgrades in the exact way you might be thinking.

Why the Engineer is Partially Correct (and Where They are Wrong)

The engineer is correct that the NEC doesn't explicitly dictate the format of a load summary. The code is more concerned with what must be included in the calculation and the factors that must be considered.

The engineer is WRONG if they think they can simply provide a service based on nameplate data or some arbitrary assumptions without a realistic understanding of the tenants' load profiles.

Here's what needs to happen


Collaboration is Key

The plaza owner and engineer must collaborate to gather information about the tenants' existing or anticipated electrical usage.2.

Information Gathering

At a minimum, the following information is required from each store to determine a realistic load demand:

Type of Business

(Restaurant, retail, office, etc.)

Square Footage



Equipment Inventory

A list of all electrical equipment, including: HVAC equipment (size in tons or BTU/hr) Lighting (estimated wattage or fixture count) Refrigeration (commercial refrigerators, freezers) Cooking equipment (ranges, ovens, fryers, etc.) Point-of-sale systems and computers Any other significant electrical loads (e.g., welders, motors, etc.)

Operating Hours



Historical Billing Data (if available)

For existing tenants, reviewing past electricity bills can provide valuable insight.3.

Load Calculation Based on NEC Article 220

Based on the information gathered, the engineer must perform load calculations for each tenant using the methods outlined in NEC Article 220. This includes:

General Lighting Load (220.12)

Based on occupancy and square footage.

Small Appliance and Laundry Loads (220.14(H))

For retail and food service establishments.

Show Window Lighting (220.14(G))



Fixed Appliance Load (220.14(D))

Individual loads like water heaters.

HVAC Load (220.12(C))

Calculate the largest of the heating or cooling load.

Motor Loads (Article 430)

For any motors used in HVAC, refrigeration, or other equipment.

Demand Factors (220.42)

Apply appropriate demand factors based on occupancy and equipment usage (e.g., restaurants often have higher demand factors).4.

Load Summary (Informal, but Essential)

The engineer must create a load summary, even if it's not a formal document with a specific format. This summary should include:

A breakdown of the calculated load for each tenant.

The total calculated connected load for the entire plaza.

The calculated demand load for the entire plaza (after applying demand factors).

The size of the new main switchboard based on the calculated demand load.

The size of each tenant's subpanel (based on their individual calculated load).

The size of the service lateral/conductors.5.

Consider Future Expansion

The engineer should also consider the potential for future expansion or changes in tenants' electrical needs. It's wise to provide some extra capacity in the new service to accommodate future growth.6.

Coordination with Utility Company

The engineer will need to coordinate with the local utility company to determine the available service capacity and ensure the new service meets their requirements.

Example Load Summary (Conceptual)

| Tenant | Type of Business | Square Footage | Calculated Load (VA) | Demand Factor | Demand Load (VA)

---|---|---|---|---|---

Store A | Retail Clothing | 2,000 | 20,000 | 0.75 | 15,000

Store B | Restaurant | 1,500 | 40,000 | 0.85 | 34,000

Store C | Office | 1,000 | 10,000 | 0.60 | 6,000 ||

Total | | | 70,000 | | 55,000 |This is a simplified example. A real load summary would be much more detailed.In conclusion:While the NEC might not explicitly mandate a perfectly formatted "load summary" in the way you're imagining, it absolutely requires that the engineer perform thorough load calculations based on the expected usage of the tenants. A responsible engineer must* gather data, perform calculations, and ensure that the new service is adequately sized to handle the anticipated load. The lack of a clearly defined term "load summary" does not relieve the engineer of the requirement to calculate the load according to Article 220. Failing to do so is negligent and could lead to serious problems. You need to push back on the engineer and demand that they perform a proper load analysis. This protects the plaza owner from liability and ensures the new electrical service is safe and reliable. It is often more cost effective and cheaper to design a correctly sized service rather than have the costs associated with equipment damage due to undersized service. Flag for review