Power lines of 22v and above are not allowed to enter the closed cabin.

yes. A closed cabin refers to a place without continuous ventilation, which may be dangerous to people because of the presence of combustible gas, toxic gas, inert gas or oxygen content below the critical value, thus restricting access. The power cord used in the closed cabin must be insulated with rubber sheath to ensure that there is no joint or damage, and the safe voltage of 36V and below must be used in the narrow cabin.