The following factors should be considered while conducting the cleaning of combustible paper dust:
Wrapping the outside surfaces of the standard plastic hose (generally a highly insulting material) with a copper wire would not prevent the buildup of electrostatic charges on the inside surfaces of the hose. Indeed, very energetic electrostatic discharges could result that are capable of igniting most combustible dust cloud atmospheres.
The use of water spray may prevent the accumulation of electrostatic charges on the inside surfaces of the hose if all the surfaces are adequately wetted and the wet surfaces are in contact with electrical ground at all times. An adequate water spray may also render the paper dust particles non-combustible. However, one may end up with electrostatically charged isolated wet surfaces (patches) that could produce energetic sparks if the water spray is inadequate or intermittent.
I suggest that you consider using an electrically grounded conductive or static dissipative hose or performing a dust explosion hazard assessment on the operation with the objective of identifying, assessing, and controlling dust cloud explosion hazards throughout the operation.