You're right, the 10-foot rule isn't explicitly stated in NEC 690.13 regarding PV disconnects. The NEC emphasizes readily accessible and, for some disconnects, accessible locations. This leads to local interpretations and potential conflicts.Here's the breakdown and how to approach this situation in NYC

Why the 10-Foot Rule Likely Originated and Why It's Important to Verify Locally
Local AHJ Interpretation

The 10-foot guideline is almost certainly a specific interpretation or enforcement practice by the NYC Authority Having Jurisdiction (AHJ). It's a common way for local inspectors to ensure accessibility and ease of operation during emergencies or maintenance.

Ease of Operation/Maintenance

A shorter distance from the main panel facilitates quicker isolation of the PV system in case of emergencies, grid issues, or required maintenance. This promotes safety for homeowners and utility workers.

Consistency

Having a standard (like 10 feet) provides consistency for installers and inspectors, reducing disputes and streamlining the permitting process.

What You MUST Do to Confirm the Requirement in NYC1. Contact the NYC Department of Buildings (DOB) Electrical Division

This is the most important step. Call or email the DOB's electrical inspection department and specifically ask about their requirements for the location of the PV disconnect in relation to the main service panel. Ask them: Do they have a specific distance requirement (like the 10-foot rule)? If so, is it a written policy or a common practice? Can they provide documentation of this requirement (a bulletin, memo, or other guidance document)? What are the specific justifications for their interpretation of "readily accessible" in this context?2.

Review Local Amendments to the NEC

NYC likely has local amendments to the NEC (New York City Electrical Code). These amendments can add, delete, or modify NEC requirements. Obtain a copy of the NYC Electrical Code (or the relevant section regarding solar) and look for specific regulations regarding PV disconnect locations. The DOB website or a licensed electrical contractor should be able to provide this.3.

Consult with a Licensed Electrical Contractor Familiar with NYC PV Installations

Experienced local contractors will be well-versed in the common practices and unspoken rules enforced by NYC inspectors. They can provide valuable insights and help you navigate the permitting process.

Why the NEC Definition of "Readily Accessible" Isn't Enough

While the NEC defines "readily accessible," the AHJ (NYC DOB in your case) has the final say on how that definition is applied in practice. They can establish more stringent requirements or interpretations based on local conditions, safety concerns, or historical practices.

Example of How NEC 690.13 Plays a Role, Even With Local Interpretation NEC 690.13(B) Disconnecting Means

Disconnecting means shall be readily accessible and suitable for the intended purpose. Even if NYC enforces a 10-foot rule, the disconnect itself still has to meet NEC standards. It has to be properly rated, labeled, and easily operable.

NEC 690.13(A) Location

Disconnecting means shall be installed at a readily accessible location either inside or outside of the building or structure. This gives options, but the 10 feet is a further constraint on these options.

Consequences of Non-Compliance

Installing a PV system that doesn't meet NYC's requirements will likely result in: Failed Inspection

The system won't pass inspection, delaying commissioning and potentially incurring fines.

Required Rework

You'll have to relocate the disconnect, adding to your costs and potentially damaging the installation.

In summary: Don't rely solely on the NEC alone for PV installations in NYC. Always* verify the local requirements with the NYC Department of Buildings and consult with experienced local electrical contractors. Your proactive investigation can prevent costly mistakes and ensure a smooth installation process. Specifically, get clarification on that 10-foot rule, where it originates, and what flexibility, if any, exists. Flag for review