Yes, the 20A breaker is likely in violation of NEC 430.62 when considered in conjunction with Table 430.
52. Here's a breakdown of why and what considerations need to be made

Understanding the Relevant NEC Sections:
NEC 430.52 (Motor Branch-Circuit Short-Circuit and Ground-Fault Protection)

This section dictates the maximum overcurrent protection device (OCPD) size for a motor branch circuit. It refers you to Table 430.52.

NEC Table 430.52 (Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices)

This table provides the maximum percentage of the motor's full-load current (FLA) that the OCPD can be sized at, depending on the type of device (inverse time breaker, fuse, etc.).

NEC 430.62 (Feeder Demand Factor)

This section deals with calculating the minimum size of the feeder conductors and the feeder overcurrent protection device. The purpose is to prevent nuisance tripping of the feeder due to motor starting inrush current.

Calculations and Analysis


Motor FLA

First, we need to find the Full Load Amps (FLA) of your 2HP, 480V, 3-phase motor. You'll find this on the motor's nameplate or in NEC Table 430.250 (Full-Load Current, Three-Phase Alternating-Current Motors). Typically, a 2HP, 480V, 3-phase motor has an FLA around

3.4 amps.2. Maximum Branch-Circuit Overcurrent Protection (NEC 430.52 & Table 430.52)

For an inverse time breaker, the maximum size is 250% of the motor FLA. 250% of 3.4 amps = 8.5 amps.
3.

Feeder Calculation (NEC 430.62)

This section allows you to size the feeder overcurrent protection larger than the individual branch circuit protection, but only to accommodate the motor's starting inrush current while still protecting the feeder conductors. The feeder overcurrent protection device cannot exceed the calculated size based on NEC 430.62 requirements.

The Problem

The 20A breaker is exceeding the maximum overcurrent protection allowed per Table 430.52. The largest inverse time breaker that is allowed is 8.5 amps for an inverse time breaker.

Why the Fuses in the Disconnect Don't Solve the Problem

While the 15A fuses are within the allowable range, they are located downstream of the 20A breaker. The 20A breaker is intended to protect both the conductors AND the motor branch-circuit. Because it is not properly sized to protect the motor, the overcurrent protection is not compliant with NEC standards.

What Needs to be Done


Reduce the Breaker Size

The upstream breaker needs to be reduced in size to match that of the protection requirements in NEC 430.52. This would require a 10-amp breaker if an inverse time breaker is to be used.
2.

Verify Conductor Ampacity

Make sure the feeder conductors from the panel to the disconnect have an ampacity of at least 125% of the motor FLA (NEC 430.22). In this case, the conductors need to be rated for at least 4.25 Amps. The conductors would need to be sized according to NEC 310.16 and should be sized to match that of the termination rating on both the breaker and disconnect.
3.

Check Motor Nameplate

Always refer to the motor's nameplate for specific FLA and any specific overcurrent protection recommendations from the manufacturer.

Important Considerations



Motor Protection

The primary goal is to protect the motor from overloads and short circuits.

Coordination

Ensure that the OCPDs are coordinated. The fuses in the disconnect should trip before the breaker under fault conditions.

Qualified Electrician

This is an electrical safety matter. All work should be performed by a qualified electrician familiar with the NEC.

In Summary:

The 20A breaker is likely a violation of NEC 430.62 and Table 430.
52. It needs to be reduced to a size that aligns with the motor's FLA and the maximum overcurrent protection allowed by the NEC. Flag for review