A listed utility-interactive inverter for a photovoltaic system is being connected to premises wiring. According to the NEC, when is it permitted to connect this inverter to the premises wiring without a grounded conductor?

• When the inverter output is less than 30 amps.
• Where the connected premises wiring or utility system includes a grounded conductor.
• Only when installed outdoors with a dedicated grounding electrode.
• When the inverter is part of a stand-alone system not connected to the utility.