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Terms and Definitions

Voltage ratings for power cords vary from 125V – 250V, which is dictated by the source power’s receptacle. The receptacle’s configuration is specific to the voltage rating to prevent any safety hazards, thus the same is true for the power cord’s plug. A 125V plug will not fit into a 250V receptacle, and vice versa.

The jacket for the power cord wiring also has a voltage rating, which dictates junior service (300V) and hard service cords (600V).

Plug and Connector Type
The type of plug required for a power cord is contingent on a few factors:

  • Power Source – where the cord draws its power
  • Geographic location – the specific country in which the cord is used
  • Voltage – whether it’s 125V or 250V
  • Amperage Capacity – each power cord is limited to a specific range of amperage capacity

Wire Gauge
The wire gauge is the size of the cord component of the cord set, which dictates the amperage capacity.

Medical Applications
A hospital grade power cord is evaluated to a higher quality standard than non-hospital grade power cords. Power cords used with North American medical equipment must be hospital-grade.

The hospital-grade plug diameter must conform to NEMA WD-6 and UL 817 standards. The blades must be solid instead of folded brass, the blades are usually nickel-plated, and the plug includes an internal cable retention device, or strain relief, to prevent any stress to the plug’s internal connections. The colors of hospital grade plugs or the cable jacket are produced to the manufacturer’s preference. Although many hospitals prefer that the plug be clear so that internal connections can be inspected visually, UL (Underwriters Laboratories) and CSA (Canadian Standards Association) standards do not mandate clear plugs, nor do they provide any restrictions on color. Most commonly, the cord sets are solid gray, or occasionally clear-blue male plugs.

Hospital-grade power cords and cord sets should carry a “green dot” to signify they have been designed and tested for grounding reliability, assembly integrity, strength, and durability. They are subject to the 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;
  • Attachment plug and receptacle standards: UL 498 and CAN/CSA C22.2 no 42.