Let's break down NEC 230.71 and how it applies to your apartment building meter stacks

NEC 230.71: Maximum Number of Disconnects
The Rule

NEC 230.71(A) generally allows up to six service disconnecting means (or sets of fuses or circuit breakers) to serve as the service disconnecting means for each service.

Key Considerations



"Service"

The definition of "service" is critical. In your case, each meter stack (North and South) is fed by its own dedicated service transformer. This means each transformer constitutes a separate "service."

"Service Disconnecting Means"

This is the main disconnect (circuit breaker or switch) that can isolate the entire service from the building's electrical system. It has to disconnect all ungrounded conductors.

How NEC 230.71 Applies to Your Situation1. Each Meter Stack is a Separate Service

Because each meter stack (North and South) is fed by a dedicated service transformer, each meter stack is considered to be an individual service as defined by the NEC.2.

Individual Apartment Meters are NOT Service Disconnects

Each apartment meter is not a service disconnecting means. The individual apartment meters are downstream of the service disconnecting means. They are branch circuits or feeders fed from the service, not part of the service itself.3.

Determining if you NEED a MCB If you have a meter center/stack with a single main breaker feeding the entire stack of 13 meters, that would qualify as one service disconnecting means. Then you would have 12 additional tenant breakers in the stack. This would be over the allowed 6 disconnect rule. If each meter has its own disconnect breaker, this would not follow the rules as there are 13 disconnects.

Conclusion Yes, NEC 230.71 applies. If you want to use individual meter disconnects without a main breaker, you would have to use a listed meter center that is specifically designed to house more than six service disconnects.Recommendations1. Consult with a Local Electrical Inspector

The best course of action is to always consult with the local electrical inspector before finalizing your design. They have the final say on code interpretation and enforcement in your jurisdiction. Show them your plans and get their specific guidance. They can help you navigate local amendments or interpretations of the NEC.2.

Consider a Listed Meter Center

There are many meter centers specifically designed to have more than six disconnects. These meter centers are tested and listed by companies such as UL. These will most likely solve your issues.

Important Considerations



Accessibility of Disconnects

All service disconnecting means must be readily accessible.

Grouping of Disconnects

NEC requires service disconnects to be grouped in a readily accessible location. Having one main disconnect (MCB) simplifies this.

Emergency Shutoff

Consider how first responders will quickly disconnect power to the building in an emergency. A single, easily accessible main disconnect is often preferred.

Future Expansion

Think about future expansion needs. A larger MCB could give you additional capacity later on.

Disclaimer: Consult with a qualified electrical engineer and your local electrical inspector to ensure your design complies with all applicable codes and regulations. Flag for review