Count coppers guarding first of electricity poles (6)
I believe the answer is:
census
'count' is the definition.
(censusing is a kind of counting)
'coppers guarding first of electricity poles' is the wordplay.
'coppers' becomes 'cus' ('Cu' can be a synonym of 'copper').
'guarding' is an insertion indicator.
'first of electricity' becomes 'e' (1st letter of 'electricity').
'poles' becomes 'ns' (North and South poles).
'e'+'ns'='ens'
'cus' placed around 'ens' is 'CENSUS'.
(Other definitions for census that I've seen before include "Head-count" , "Official body count?" , "People count" , "Population survey" , "Periodic count as of population" .)