A.系統(tǒng)中不引出N線B.系統(tǒng)中不引出PE線C.系統(tǒng)中N線與PE線合用一根導(dǎo)線D.系統(tǒng)中N線和PE線嚴格分開
A.48V B.36V C.24V D.12V及以下
A.20% B.30% C.40% D.50%