Okay, let's break down this scenario and address your question regarding the Ronk transfer switch and its service entrance (SE) rating.

Understanding the Situation Pad Transformer

This is your source of power from the utility.

Rack

You're mounting your equipment (transfer switch and panels) on a rack at grade level.

Two 200A Panels

You're feeding two separate 200A panels. One is backed up by a generator via the Ronk transfer switch.

Ronk Transfer Switch

A 200A transfer switch to switch between utility power and generator power for ONE of the panels.

CT Metering

The utility company (POCO) will be metering the power using current transformers (CTs). This is crucial because it affects where the service disconnect could be.

The Key Question: Is the Ronk the Service Disconnect?

This is the core of the issue. The answer dictates whether you need an SE-rated Ronk. Let's consider two possibilities

Scenario 1: The Ronk is NOT the Service Disconnect

You Intend to Label the Panels as Emergency Disconnects

You're planning to have the 200A panels themselves act as the main disconnects for each respective service. You will have a separate panel that has a normal and emergency panel.

CT Metering Implication

With CT metering, the service point of demarcation (where the utility's responsibility ends and yours begins) is upstream of the CTs. Typically, utilities will provide the service entrance conductors to the line side of your CTs.If the above is true, and your POCO agrees that the utility is stopping at your CT Metering cabinet then

you may NOT need an SE rated Ronk because the 200A panel is acting as the emergency disconnect.

Scenario 2: The Ronk IS the Service Disconnect Utility Requirement

The utility may require you to have a single service disconnect before the Ronk and the panels, even with CT metering. This is often driven by their safety practices and/or local codes.

Code Requirement

Electrical codes require a service disconnect to be readily accessible.If this is the case, then you

DO need an SE-rated Ronk.

Why an SE Rating Matters

An SE (Service Entrance) rated switch is designed and tested to meet specific requirements for use as the main disconnect. Key features include: Suitable for Use as Service Equipment

Listed specifically for this purpose.

Short Circuit Current Rating (SCCR)

Must be able to withstand the available fault current at the service entrance. This is critical for safety.

Markings

Clearly marked as suitable for use as service equipment.

Neutral Bonding Provisions

May have specific requirements for bonding the neutral conductor.

Recommendations and Next Steps1. Consult with the POCO (Crucial)

This is the most important step. They dictate where the service entrance is and what is allowed. Discuss: Their requirements for the service disconnect. Do they require a single disconnect before any other equipment? Whether they consider the service entrance to be upstream of the CTs. Whether they will allow your arrangement of two 200A panels acting as service disconnects (one normal, one backed by a generator).2.

Check Local Electrical Codes

Your local AHJ (Authority Having Jurisdiction) may have specific requirements regarding service disconnects and generator connections.3.

Consider the Cost

While the SE-rated Ronk is more expensive, it might be a necessary expense to ensure compliance and safety. Weigh this against the potential risks and costs of non-compliance.4.

Documentation

Get everything in writing from the POCO. This is crucial in case of future inspections or issues.5.

Consider a Single Service Disconnect

An alternative would be to install a single, separate, service rated disconnect switch ahead of BOTH panels. This would simplify the requirements for the Ronk and panels. The service disconnect switch would need to be rated for 400A.

In summary, the definitive answer hinges on the POCO's requirements and the local electrical code. Start with a conversation with the utility company to get their specific guidelines. Once you have that information, you can make an informed decision about the Ronk transfer switch.Important Considerations Safety

Never compromise on safety to save money. Ensure that all equipment is properly rated and installed.

Accessibility

The service disconnect must be readily accessible.

Bonding and Grounding

Proper bonding and grounding are essential for safety and code compliance.

NEC (National Electrical Code): Be familiar with the relevant sections of the NEC, especially those pertaining to service entrances, disconnects, and generators.Good luck with your project! Let me know if you have further questions. Flag for review