The employer shall ensure at a construction site of a building or other construction work that,—
(a) no trestle scaffold is constructed with more than three tiers or if its working platform is more than four point five metres above the ground or floor or other surface upon which such scaffold is erected, such trestle scaffold is designed by professional engineers and has the approval of the principle employer, if any and of the Chief Inspector before being taken into use;
(b) no trestle scaffold is erected on a suspended scaffold;
(c) no cantilever or jib scaffold is used unless it is adequately supported, fixed and anchored on opposite side of its support, has out–rigger of adequate length and wherever necessary, sufficiently supported and braced to ensure safety and stability of such scaffold; and
(d) no working platform resting on bearer left into a wall at one end and without other support is used, unless such bearer is of adequate strength, braced through the wall and securely fastened on the other side;