  We describe a simple method of extending AdS_5 black string solutions of 5d
gauged supergravity in a supersymmetric way by addition of Wilson lines along a
circular direction in space. When this direction is chosen along the string,
and due to the specific form of 5d supergravity that features Chern-Simons
terms, the existence of magnetic charges automatically generates conserved
electric charges in a 5d analogue of the Witten effect. Therefore we find a
rather generic, model-independent way of adding electric charges to already
existing solutions with no backreaction from the geometry or breaking of any
symmetry. We use this method to explicitly write down more general versions of
the Benini-Bobev black strings and comment on the implications for the dual
field theory and the similarities with generalizations of the Cacciatori-Klemm
black holes in AdS_4.
