青云翻译

(7) All the power lines and switches to set the insulation must be protected in the best condition,

(7) all power cords and switches must be protected in the best possible insulation condition,

(7) all power lines and the switch establishment must protect in the best state of insulation,

( 7) All of the power lines and switch setting must be protected in the best-insulated.

(7) all power cords and switches must be protected in the best possible insulation condition,