Ask The Expert

Amplify Hospital-Grade Power with NEMA 5-15, 5-20, 6-15, 6-20 Cords!

MedWrench spoke with Interpower's R.J. Balch about their hospital-grade plugs and its impact on medical professionals and settings.

Thu Jul 01 2021By Interpower

Whether cutting-edge vaccine research in a laboratory, a life-support unit in a large hospital, or a heart monitor in a small clinic, Interpower’s NEMA Hospital-grade plugs deliver the correct amperages and voltages to meet the ratings needed for today’s sophisticated medical equipment.

NEMA hospital-grade plugs can be molded or hand-wired in several colors—clear, black, or gray—onto any length of 18, 16 or 14 AWG SJT cable. Coupled with C13 and C19 connectors, NEMA hospital-grade plugs make best-in-class cord sets. The color of choice for many medical institutions, however, is the clear, see-through Interpower hospital plug.

“Many medical professionals prefer clear plugs to solid colors,” says Dan Ford, Technical Support Specialist at Interpower. “The clear plug allows you to see the connected wires and the anchor rings that hold the connected wires and components in place in order to inspect for damage.”

The Mark of Excellence

NEMA 5-15, 5-20, 6-15, and 6-20 Hospital-grade plugs and receptacles bear the green dot, signifying the plugs have been rigorously tested to meet power supply cord standards UL 817 and C22.2 No. 21-14 requirements for hospital-Grade power cords and cord sets:

The UL 817 Abrupt Removal Test (UL 817, is for hospital-grade plugs, which begins by inserting a hospital-grade plug into a socket. The cord containing the ground, neutral, and line wires (attached to the plug) is then attached to a 10-lb weight. The weight is then dropped 24 inches to abruptly disconnect the plug from the socket to see how far the blades have bent, and to see if the wires have lost electrical continuity.

Standard NEMA 5-15 plugs are put to the test as well. The UL Abrupt Pull Test (UL 817, is for all standard NEMA 5-15 plugs. A 2 ½-lb weight is attached to a plug’s cord and dropped 25 times from the connected plug and socket. Before the initial drop, three lights on the test equipment glow red showing electrical continuity. However, during the test, if one of the three wires fail (line, neutral, and ground) and one or more lights go out, the test is considered a failure.

“We test more than is required by the standards for our own benefit,” Product Development Manager Ron Barnett says. “We go beyond the standards because it lends better reliability to our design—products become more reliable in that regard.”

The hospital-grade plug diameter conforms to NEMA WD-6 specifications standards: 

“(1) the blades must be solid instead of folded brass, (2) the blades are usually nickel-plated, (3) the plug includes an internal cable retention device or strain relief to prevent any stress to the plug’s internal connections and (4) NEMA plug and receptacle are marked “Hospital-grade” and with a green dot.” The retention device Interpower uses in (3) are stainless steel rings to solidly hold the connections in place.

UL 498 and UL 60601 also list requirements for fault current, terminal strength, ground contact temperature and resistance, assembly security, cord grip strain relief and cord pull, and other durability and impact tests of the material.

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