Where electricity of voltage exceeding 650 V is transformed, converted, regulated or otherwise controlled in substations or switching stations including outdoor substations and outdoor switching stations or in street boxes constructed underground, the following provisions shall be ensured, namely: –
(i) substations and switching stations shall preferably be erected above ground, but where necessarily constructed underground due provisions for ventilation and drainage shall be made and any space housing switchgear shall not be used for storage of any materials especially inflammable and combustible materials or refuse; and
(ii) (a) outdoor substations except pole type substations and outdoor switching stations shall, unless the apparatus is completely enclosed in a metal covering connected with earth, the said apparatus also being connected with the system by armoured cables, be protected by fencing not less than 1.8 metre in height or other means so as to prevent access to the electric supply lines and apparatus therein by an unauthorised person and the fencing of such area shall be earthed efficiently; and
(b) transformer mounting structure shall be as per the regulations notified by the Authority under clause (e) of sub-section (2) of section 177 of the Act.