The employer shall ensure at a construction site of a building or other construction work that,—
(a) a shovel or an excavator, whether operated by steam or electric or by internal combustion, used for such work, is constructed, installed, operated, tested and examined as Section 40 (2) (p) 42 required under any law for the time being in force and the relevant national standards ;
(b) excavator equipped for use as a mobile crane is—
(i) examined and tested in accordance with the requirements for such mobile crane under these rules ; and
(ii) fitted with an automatic safe working load indicator ;
(c) buckets or grabs of power shovels are propped to restrict the movement of such buckets or grabs while being repaired or while the teeth of such buckets or grabs are being changed.