应用等级的分类是根据应用的环境来定义的:
Class A: General access, hazardous voltage, hazardous power applications
Modules rated for use in this application class may be used in systems operating at greater than 50 V DC or 240 W, where general contact access is anticipated. Modules qualified for safety through this part of IEC 61730 and IEC 61730-2 and within this application class are considered to meet the requirements for safety class II.
Class B: Restricted access, hazardous voltage, hazardous power applications
Modules rated for use in this application class are restricted to systems protected from public access by fences, location, etc. Modules evaluated within this application class provide protection by basic insulation, are considered to meet the requirements for safety class 0.
Class C: Limited voltage, limited power applications
Modules rated for use in this application class are restricted to systems operating at less than 50 V DC and 240 W, where general contact access is anticipated. Modules qualified for safety through this part of IEC 61730 and IEC 61730-2 within this application class are considered to meet the requirements for safety class III.