Engineers with special gear maybe in industrial installation (8)
I believe the answer is:
refinery
'industrial installation' is the definition.
(eg an oil refinery)
'engineers with special gear maybe' is the wordplay.
'engineers' becomes 're' (abbreviation for Royal Engineers).
'with' means one lot of letters go next to another.
'special gear maybe' becomes 'finery' (formal or fancy clothing).
're'+'finery'='REFINERY'
'in' is the link.
(Other definitions for refinery that I've seen before include "Plant for purifying, oil say" , "Industrial plant for purifying a crude substance" , "Factory which removes impurities etc from crude substances" , "Chemical plant" , "Industrial plant for purifying crude substances" .)