IEC 62353:2014 - Which method do you use?

The decision tree in the standard will walk you through the choice.

IEC 62353 is an internationally recognized standard and provides an alternative to the more rigorous IEC 60601-1 testing. We would use IEC 62353 outside of acceptance or type testing. Using IEC 60601-1 repeatedly can shorten the life of the medical device (Tests like the 25A PE resistance and/or 110% mains on applied parts testing). Choosing IEC 62353 will shorten the amount of testing while providing the minimum accepted electrical safety tests.

Using IEC 62353 vs IEC 60601-1 reduces the amount and severity of testing.

The first question is what electrical safety class is your device? Depending on your answer will tell you if you need to do PE (protective earth resistance) or not. The next step is whether you need to do insulation resistance testing. You would need to do insulation resistance testing if the Local National Electrical Safety code requires it or if the manufacturer of the medical device requires it.

The next area of testing is equipment leakage current. We need to know if there is an on/off switch on the medical device. If no, our test method would be the alternative method. If yes, then we need to determine if the medical device is isolated from earth. If not, then we use the differential method. If yes, we have 3 choices; IEC 60601-1 tests for leakage current, IEC 62353 direct method, or we can choose to do a differential method. If IEC 60601-1 is chosen, then refer to that standard for tests and limits.

If we test with direct or differential methods, we then move to applied part leakage testing. Are the applied parts F-Type (BF or CF)? These types of applied parts are floating. Also, we need to know if there is active circuitry in applied part. If Type F applied part and active circuitry in the applied part, then applied part leakage must be done with power on. This is not mains on applied part or lead isolation test but rather leakage to ground. If there is no active circuitry, turn the device to off and then conduct the leakage to ground measurement.

Use of the IEC 62353 standard can lessen the amount of testing versus testing to IEC 60601-1  and may not put as much stress on the medical device. There are three different ways to test using IEC 62353; direct, differential, and alternative. Each device under test should be evaluated for which method of testing is applicable.