You've identified a very common and important situation with series ratings. Let's break down the implications and options

Understanding the Problem
Series Rating Validity

The series rating's validity hinges on whether all the components between the upstream overcurrent protective device (OCPD) and the downstream device are explicitly included in a tested and listed series combination. You've correctly identified that the JD breaker is not part of the tested series rating.

JD's Impact

The presence of the JD breaker, which is not part of the listed series combination, invalidates the series rating that would otherwise exist between the upstream JJ breaker and the downstream EDB breakers. The fact that the JD breaker has an interrupting rating lower than the available fault current is a major concern.

Code Relevance

NEC 110.3(B) is relevant here. It states that listed or labeled equipment must be installed and used in accordance with any instructions included in the listing or labeling. Using the system in a way that isn't consistent with the series rating, effectively violates this code requirement, especially if the fault current is greater than 18kAIC.

Why the Series Rating is Invalid

The series rating test for the JJ/EDB combination doesn't account for the behavior of a JD breaker. The series rating relies on the coordinated operation of the upstream and downstream breakers to limit the let-through current and energy. The JD breaker, with its potentially different trip characteristics and current-limiting capabilities, throws off that coordination. Specifically, the test is setup under the assumption that it will allow the EDB breaker to clear the fault before the upstream breaker. If the JD breaker trips first, it will not be able to clear the fault current due to the available fault current being greater than its rating.

Options and Recommendations1. Most Desirable: Remove the JD Main Breaker (if possible and permissible by code)

This is often the best solution. If the panelboard's design allows and code permits (e.g., no required local disconnect for maintenance, etc.), remove the JD main breaker.

Verify Busbar Rating

Crucially, ensure the panelboard's busbar rating is equal to or greater than the ampere rating of the upstream JJ breaker (200A in your case). The busbar needs to be able to handle the potential fault current until the upstream breaker clears the fault.

Reconnect Directly

Connect the load-side conductors directly to the panelboard's busbars, maintaining proper termination methods.

Advantages

Restores the valid series rating between the JJ and EDB breakers. Simplifies the system. Reduces potential failure points.2.

Evaluate the Need for the Main Breaker Ask yourself why the breaker was installed to begin with. Is it a safety disconnect? Or just overcurrent protection? If there are other disconnects that can perform the function, then it's best to remove it. You will need to verify the installation meets all requirements for overcurrent protection, including those of Article 240 of the NEC.3. Consider a Different Panelboard (Least Desirable in this case)

Replace the entire panelboard with one that does not have a main breaker, or one that uses a main breaker that is part of a properly tested and listed series rating with the upstream JJ breaker. This is generally the most expensive and disruptive option.4.

Downstream Breakers The current interrupting rating of the downstream EDB branch breakers must meet or exceed the available fault current.

Important Considerations Available Fault Current Calculation

Always calculate the available fault current at the panelboard location. The series rating is only valid if the available fault current is less than or equal to the series rating value (65kAIC in your case). If the available fault current exceeds the 65kAIC rating, you must implement a solution that reduces the fault current to acceptable levels or increases the interrupting rating of the protective devices.

Documentation

Keep thorough documentation of all changes made, including the reasoning behind the changes, calculations of available fault current, and relevant series rating information.*

Qualified Personnel

All work must be performed by qualified electrical personnel and must comply with all applicable codes and regulations.

In summary, the presence of the JD breaker invalidates the series rating. Your best option is likely to remove the JD breaker, provided the busbar rating is adequate and removal is code-compliant. This resolves the series rating issue and eliminates a point of potential failure. Always consult with a qualified electrical engineer or other competent professional to ensure compliance with all applicable codes and regulations. Flag for review