Covers and doors are part of the enclosure. When they are closed, they shall provide the degree of protection specified for the enclosure. When ventilation openings are incorporated in covers or doors, reference is made to 5.5.5.
Two categories of covers or doors are recognized with regard to access to the compartments
of the prefabricated substation.
a) Those which need to be opened for normal operation (removable covers, doors). These shall not require tools for their opening or removal. They shall be provided with locking facilities unless the safety of persons is assured by a suitable interlocking device.
b) All other covers, doors or roof. They shall be provided with locking facilities or it shall not be possible to open or remove them before doors used for normal operation have been opened. They shall require tools for their opening or removal.
The doors shall open outwards at an angle of at least 90° and be equipped with a device able to maintain them in an open position. Below ground-level prefabricated substations require an access hatch, providing adequate safety for personnel and the passer-by. It shall be possible for a single person to operate this hatch. It shall be possible to secure the access hatch to prevent closure whilst operators are within the substation or working on the equipment from outside the substation.