What is the difference between TYPE B and TYPE BF?

Westwing

Registered
Is there anyone know the difference between TYPE B and TYPE BF?
From Table 3 of IEC 60601-1 2020, the allowable values are the same between TYPE B and TYPE BF, so the requirement are the same. I guess the difference comes from the structure of the product itself. Would you please show an example of TYPE B product? Thanks in advance!
 

Benjamin Weber

Trusted Information Resource
You are right, the values for leakage currents are the same for B and BF type applied parts.

But a closer look at table 4 reveals, that there are additional limits/test conditions for BF type applied parts. These special test conditions also show the difference between B and BF: F-type applied parts provide a higher degree against electric shock. The F stands for "floating". This means, that F-type applied parts separate the patient from ground/earth connections. This is necessary for applications, where the applied part is used to transport (electric) energy to or from the patient. Usually a good conducting contact between patient and applied part is needed (e.g. electrodes). In these applications there is risk that the patient is connected to a potentially hazardous voltage via the applied part. In this single fault or special test condition (voltage on the applied F-type applied part) the applied part still protects the patient by limiting the patient leakage current and by providing 1 MOPP against mainst voltage between the patient connections ans all other parts (incl. ground/earth connection, e.g. PE).

B applied parts do not provide this degree of protections against electric shock. Such applied parts have mainly only mechanical functions, such as patient supports. In contrast to F-type applied parts these are allowed to have a PE connection as one MOPP (which is explicitly not alloed for F-type).

I hope this helps.
 
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