Utility External Disconnect Switch Report

Download the one-page Summary (PDF, 283KB)or the full report (PDF, 1.2MB) View the summary presentation.

Overview

Image of Utility External Disconnect Switch one-page summary
This report documents the safe operation of photovoltaic (PV) systems without a utility external disconnect switch (UEDS) in several large jurisdictions. It explains the rationale for eliminating UEDS:

Why the Report is Important

Regulators must decide the question of UEDS requirements as they develop or revise interconnection rules for small renewable energy generators. The report includes important information on this topic and a recommendation for regulators.

Issue

Some states and utilities require installation of UEDS between PV power systems and the utility grid as a device to ensure line worker safety.  However, eight states and many major utility companies have recognized that safety devices and features already part of all Code-compliant PV systems make the UEDS redundant and have eliminated its requirement.

Solar America Board for Codes and Standards Recommendation

The recommendation of this report is to eliminate the requirement for UEDS for all small, inverter-based systems in all jurisdictions.  With the inherent safety features built into all UL-listed PV inverters, the UEDS is functionally unnecessary and provides little, if any, additional safety.

For customers with self-contained meters (including almost all residential and small commercial customers), the meter itself is already fully capable of providing the functions required of the switch (i.e., a visible, physical, lockable separation of the system from the utility).  At the very minimum, these customers should be excluded from any UEDS requirement.