NEMA 10 connectors are a now deprecated type that had formerly been popular in the United States for use with high-power electric clothes dryers, kitchen ranges, and other high-power equipment. NEMA 14-30R and -50R connectors have generally replaced NEMA 10 equipment for these applications. NEMA 10s are classified as 125/250 V non-grounding (hot-hot-neutral), and were designed to be used in a manner that indirectly grounds the appliance frame, though not in the manner consistent with most modern practice. The older practice was common before the requirement of a separate safety ground was incorporated in the National Electrical Code.