Classification of USB DC operated medical equipment

Roland chung

Trusted Information Resource
Hi everyone,

Does the latest standard (which I haven't checked lately) have some clarification regarding the classification of USB DC-powered medical equipment? The medical industry seems to classify these products as class II. But it is true that the USB DC-powered medical equipment is ultimately connected to the supply mains through AC/DC adapter.

Stay healthy,
Roland
 

Peter Selvey

Leader
Super Moderator
The origin of Class I and II is 100% related to the mains supply, so a medical device that does not itself connect to the mains supply itself is, in principle, neither Class I or Class II. It should be agnostic, irrelevant, not applicable.

Unfortunately the standard does not say this directly.

The definition of Class I is 100% related to mains supply. You cannot have Class I equipment without a mains supply.

The definition of Class II is essentially being not Class I. So, even equipment without a supply mains can end up being Class II. This includes medical devices powered by a separate power supply (such as USB 5Vdc). But this is likely to be a mistake.

Outside of Clause 6 and 7.9, every reference to Class II is only relevant if there is a mains supply.

For example, Clause 7.2.6 appears to require the Class II symbol to be marked, but the title of the clause is "connection to the supply mains". So it is only applicable if there is a supply mains. If you search the standard for the term "Class II", every clause outside of clause 6 and 7.9 will be not applicable if there is no mains in the device itself.

Of course, 6 and 7.9 remains. This means that, strictly speaking the manufacturer needs to identify the device as Class II in the instructions for use and technical description. And the report writer needs to identify it as Class II. But it's a meaningless classification.
 
Top Bottom