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.
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.
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.