4.2 Fault conditions
PDS shall be designed to avoid operating modes or sequences that can cause a fault condition
or component failure leading to a hazard, unless other measures to prevent the hazard are
provided by the installation.

Protection against thermal hazards and electric shock shall be maintained in single fault
conditions as well as under normal conditions.

Circuit analysis shall be performed to identify components (including insulation systems) whose
failure would result in a thermal or electric shock hazard. The analysis shall include the effect
of short-circuit and open-circuit conditions of the component. The analysis need not include
power semiconductor devices if equivalent testing is accomplished during short-circuit tests, or
components which have been determined to have an insignificant probability of failure during
the expected lifetime of the PDS. See 5.2.3.6.4 for test.失效分析必須含短路與斷路

NOTE It is possible that no critical components will be revealed by the analysis. In this case, no component failure testing is required.非重要零件,不須執行失效測試

Consideration shall be given to potential safety hazards associated with major component parts
of the PDS, such as motor rotating parts and flammability of transformer and capacitor oils.
失效分析必須考量潛在安全相關主要零件,例如馬達轉動,變壓器著火及含油電容器