In this article, Interpower guides readers through the maze of medical cord compliance, with a focus on some country specific requirements from North America, Australia and Japan.
For a century, AC power has played vital roles in the welfare of patients and staff in hospitals worldwide. Today, hospital-grade power cords, such as those manufactured by Interpower, are ruggedly designed to provide correct amperages and voltages for a range of medical equipment such as CT Scanners, X-ray machines, heart monitors and treadmills, while maintaining patient safety.
Interpower North American (NEMA) 5-15, 5-20, 6-15 and 6-20 hospital-grade cords are tested beyond UL 817 and CSA C22.1 no. 21 agency standards. The UL 817 Abrupt Removal Test is a rigorous hospital-grade cord test. A hospital-grade plug is plugged into a socket, its cord attached to a 10-lb weight, which is dropped to abruptly disconnect the plug from the socket to see how far the blades have bent and if the wires have lost electrical continuity. The hospital-grade certified ‘green dot’ is found on both the NEMA and the Japanese JIS 8303 plug, the latter meeting JIS T 1021 hospital-grade standards.
All Interpower cords must pass the Abrupt Pull Test, which is a standard NEMA 3-conductor cord test. A 2.5-lb weight is attached to the plug’s cord and dropped 25 times from the connected plug and socket. Before the initial drop, three lights on the test equipment show electrical continuity. If a wire fails (line, neutral and ground) and one or more lights go out, the test is considered a failure.
All Interpower hospital-grade plugs contain stainless steel rings inside to secure the conductors in both molded and hand-wired hospital-grade plugs, ensuring electrical continuity—the crimped conductors remain solidly clamped to maintain AC power when needed most.
Hospital-grade cord length is also important. Interpower’s technical support specialist, Dan Ford, said: “If you’re using medical cords longer than 15 ft, it’s difficult to meet the standard requirements for resistance and leakage current. You don’t want high levels of electromagnetic interference attached to the patient.”
An example of international hospital-grade standards comes from an International Electrotechnical Commission (IEC) requirement for the jackets of hospital-grade cords used near hospital beds to maintain their abrasion resistance when encountering the wheels of hospital beds (IEC 60601-2-52). This standard ensures that wheels rolling over or sitting on the cord do not cut, slice or shred the outer jacket which may expose bare wire—the cord jacket must be of the H05-BQ-F variety. Country-specific agencies such as UL, CSA and VDE have created safety standards through testing methodologies that have transformed typical household cords into robust and reliable cords for the medical community.
Australia hospital-grade cords and plugs must meet AS/NZS 3200 and AS/NZS 3112 standards respectively. An Australian rewirable three-pin plug must be clear or see-through. For molded plugs, clear or colored is optional. The preference for Australian hospitals is orange cable and a clear plug.
In Japan, cord plugs and sockets must carry the PSE approval mark under DENAN, a Japan Ministry of Economy, Trade and Industry (METI) mandate. Japan uses two frequencies: 50 Hz and 60 Hz, with the Fuji River used as a geographical boundary for the two frequencies.
EN 60601 is the medical equipment standard for European countries. Non-European countries follow the IEC 60601-1 medical standard (except for China, Korea and Japan). There are over 100 medical equipment standards in IEC 60601. The most general and inclusive is IEC 60601-1.
