Hospital-Grade Standards for Power Cords and Other Power System Components for Global Markets

While a number of countries have standards in regards to overall medical equipment, a few countries have related component requirements (e.g. plugs and cords). For the countries that do have hospital-grade or medical application standards on components, it is important to know what the requirements are so as to comply with that country or region’s rules.

Fig. 1 – Danish, Australian, and North American hospital/medical-grade plugs.

The countries/regions that have hospital-grade or medical application standards on specific components include: Australia/New Zealand, Denmark, Japan, and North America. Power cords and cord sets as well as plugs and sockets are subject to special rules. Aside from these regions, there is no differentiation for plugs, sockets, and cords used in a medical setting versus a non-medical setting. But some countries have standards for overall medical equipment, which is different than specific components.

Medical Applications in Australia/New Zealand

Medical equipment must meet the AS/NZS 3200 standard. There are no special requirements for plugs, only preferences. All Australian plugs must be approved to AS/NZA 3112. In Australian medical applications, it is preferred by some hospitals to have a clear, transparent plug and an orange, flexible cable. These plugs and connectors must carry one of the many Australian approvals. If you are exporting to Australia or New Zealand, you should contact your end customer for guidance.

Medical Applications in Denmark

The Danish hospital-grade plug and socket are recommended for use in medical applications and specifications per Standard SB 107-2-D1. The socket is designed to prevent “normal equipment” from being connected and disrupting the mains circuit in specific medical settings. Some hospitals may have a preference to red cords, but it is not a requirement of the standard. (See Figure 1)

Hospital-Grade Requirements in Japan

DENAN is a mandatory national law administered by Japan’s Ministry of Economy, Trade, and Industry. Cords, plugs, and sockets must carry the PSE approval mark. The PSE mark is the minimum legal requirement for plugs. If you want to market your plugs as “hospital-grade,” you may perform in-house tests required by JIS T1021 and self-declare as “hospital-grade” conforming JIS T1021. UL may be able to perform tests per JIS T1021 and issue an informative report. Alternatively, you may get a JIS mark when your products and factory comply with JIS requirements. You will need to submit to a Japanese testing laboratory who is accredited by METI for the JIS Marking System.

Hospital-Grade Requirements in North America

Fig. 2 – North American NEMA 5-15 gray, black, and clear plugs.

Hospital-Grade Standards Hospital-grade plugs, sockets, and cable mount connectors are subject to special requirements contained in the following standards: Medical equipment standards—UL 60601-1 and CAN/CSA C22.2 no. 21; Power supply cord standards— UL 817 and CAN/CSA C22.2 no. 21; and Attachment plug and receptacle standards—UL 498 and CAN/CSA C22.2 no. 42. The hospital-grade plug diameter conforms to NEMA WD-6 and UL 817 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. (See Figure 2)

Specifically, they must meet the requirements of UL 498 and UL 60601 for abrupt plug removal, ground pin retention, fault current, terminal strength, ground contact temperature and resistance, assembly security, cord grip strain relief and cord pull, and various durability and impact tests of the material.

North American hospital-grade cords must utilize NEMA plugs carrying the “green dot” signifying that they have been designed and tested to UL 817 and CAN/CSA C22.2 no. 21 as hospital-grade power cords and cord sets. Specifically, UL 60601-1 sections 57.2 and 57.3 require that “patient care equipment” used in the “patient vicinity” must use hospital-grade attachment plugs. “Patient care equipment” and “patient vicinity” are defined in UL 60601-1 sections 2.12.19 & 2.12.20. (See Figure 3)

Currently the UL 498 and 817 standards only allow the NEMA 5-15, 5-20, 6- 15, and 6-20 straight blade devices to be marked “hospital-grade.” CSA will allow the NEMA 1-15 if double insulated and meets requirements.

International Conductor Color Coding

Fig. 3 – North American NEMA 5-15 plug with green dot.

It is recommended to use power cords incorporating the international brown, blue and green/yellow conductor color coding in place of the traditional North American black, white, green conductor color coding. Wiring various country specific power cords to equipment before export, including shipment to the US, is simplified when standardizing on the international color coding system. Both the US and Canadian national electrical codes, as well as UL and CSA standards, allow the use of the IEC brown, blue, and green/yellow conductor color coding.

Fusing and Filtering

Special medical requirements place significance on fusing and filtering when selecting power entry modules and other components used in medical equipment. Patient-connected medical equipment can be subjected to low-leakage current requirements. The use of a low leakage filter in the 5μA range at 250VAC is desirable. In addition, fusing of both line and neutral connectors may be required (i.e., double fusing).

International Medical Markets

Other international markets in regards to medical equipment, including European markets, typically must meet the EN/IEC 60601-1 standard. At this time, there are no special performance or construction requirements for cord sets used in these applications. Cord sets usually are Class I (with ground), PVC, and black in color. You should also pay particular attention to other requirements such as earth impedance and leakage current.

This article was written by Ron Barnett, Project Manager, Interpower Corporation, Oskaloosa, IA. For more information, Click Here " target="_blank" rel="noopener noreferrer">http://info.hotims.com/55585-164.