You've spotted a subtle but important change in the NEC. Let's break it down

Your Analysis is Correct

Yes, your reading of the current (2023 NEC) language is accurate. The key changes are: The Shift in Language

The change from "not over 15" to simply "15" in Table 210.21(B)(3) is significant.

The "Not Less Than" Requirement

210.21(B)(3) now states receptacle ratings "shall not be less than" the values in the table.This combination means: A 15-amp circuit can use 15-amp receptacles. Since "not less than" is the only constraint, a receptacle with a higher rating than 15 amps would also meet the minimum requirement, meaning a 20-amp receptacle is permitted on a 15-amp circuit.

Why the Change (Probably)

The likely reasoning behind this change is related to practicality and cost: Availability and Cost

20-amp receptacles are often more readily available (and sometimes cheaper) in bulk quantities than 15-amp receptacles. This simplifies purchasing and stocking for contractors.

Standardization

Using 20-amp receptacles throughout a building can simplify installation and future modifications.

No Inherent Safety Issue

The circuit is still protected by a 15-amp breaker. A 20-amp receptacle by itself doesn't allow overcurrent.

Where the Protection Comes From (and Remaining Concerns)

You're right to be concerned about the potential for overloading the circuit. Here's how the code tries to address that: Circuit Breaker Protection

The 15-amp circuit breaker is the primary defense against overload. It will trip if the total load on the circuit exceeds 15 amps.

Cord and Plug Compatibility

The NEMA configurations are designed to prevent plugging a 20-amp appliance into a 15-amp receptacle. A 20-amp appliance should have a NEMA 5-20P plug, which should not fit into a NEMA 5-15R receptacle.

The Catch (and where problems can arise)

While the code allows this, there are still potential issues and reasons why some electricians still avoid using 20-amp receptacles on 15-amp circuits: User Perception

A user might see a 20-amp receptacle and mistakenly believe the circuit can handle a larger load than it actually can. This is where education and clear labeling (if required by the AHJ or specification) become important.

Extension Cords and Adapters

People use extension cords and adapters, which can bypass the NEMA plug configuration safety. Someone could use an adapter to plug a 20-amp appliance into the 20-amp receptacle on a 15-amp circuit.

"I'll just replace the breaker..." An unscrupulous or uninformed person could replace the 15-amp breaker with a 20-amp breaker, leading to overloaded wiring and a fire hazard. (This is always a risk, regardless of the receptacle type.) AHJ Discretion

While the NEC permits it, a local Authority Having Jurisdiction (AHJ) might have stricter interpretations or local amendments that prohibit it. Always check with your local AHJ.

In Summary

The NEC does* allow 20-amp receptacles on 15-amp circuits with multiple outlets. The protection comes from the 15-amp circuit breaker. However, awareness of the potential for misuse and the importance of proper education are crucial. Always consult with your local AHJ for clarification or local amendments. Also, carefully consider whether the benefits outweigh the risk of potential user misinterpretations on a job-by-job basis. Flag for review