In my view, ITC against Lift will be available for following reasons:
A. Here, I am assuming that subject 'Lift' is shown as separate asset in tax-payer's Balance-Sheet and same is not capitalised under the head 'Building' (which already has staircase/s) but shown as separate asset under Plant & Machinery (being 'additional facility' provided to the occupants / tenants of the building).
B. What is blocked u/s sub-clauses (c) & (d) of Section 17(5) is 'Construction' of immovable property. For the purposes of clauses (c) and (d), the expression “construction” includes re-construction, renovation, additions or alterations or repairs, to the extent of capitalisation, to the said immovable property.
B. Said Lift is not 'constructed' but assembled / erected at site. And there are difference in the activity of 'construction' & assembly / erection as can be seen from definition of works contract services given under Section 2(119) of the CGST Act, 2017 which reads as follows:
"“works contract” means a contract for building, construction, fabrication, completion, erection, installation, fitting out, improvement, modification, repair, maintenance, renovation, alteration or commissioning of any immovable property wherein transfer of property in goods (whether as goods or in some other form) is involved in the execution of such contract;"
C. Once tax-payer has NOT received any services of 'construction' but received goods & services (i.e. works contract u/s 2(119) in nature of erection / installation of an immovable property), there is no question of barring ITC sub-clauses (c) & (d) of Section 17(5). Bar of ITC u/s sub-clauses (c) & (d) of Section 17(5) is only for 'Construction' and same is NOT for 'Erection / Installation'. And this view of mine has got nothing to with explanation given after Section 17(6).
D. Moreover, as subject cost is NOT capitalised under the head 'Building' by the tax-payer (which already has staircase/s) but shown as separate asset under Plant & Machinery in his balance-sheet (being 'additional facility' provided to the occupants / tenants of the building), this is another reason NOT to deny ITC using sub-clauses (c) & (d) of Section 17(5). This view of mine is considering 'explanation given after Section 17(5)(d) read with explanation given after Section 17(6)'. In effect, tax-payer got two immovable properties (one is 'Building' & other is 'Plant & Machinery').
These are ex facie views of mine and the same should not be construed as professional advice / suggestion or recommendation.