  We study current fluctuations in a phase coherent Y-shaped conductor
connected to external leads and voltage probes. The voltage probes are taken to
have finite impedances and thus can cause voltage fluctuations in the circuit.
Applying the Keldysh formulation and a saddle point approximation appropriate
for slow fluctuations, we examine at zero temperature the feedback effects on
the current fluctuations due to the fluctuating voltages. We consider
mesoscopic Y-shaped conductors made of tunnel junctions and of diffusive wires.
Unlike two-terminal conductors, we find that for the Y-shaped conductors the
current moments in the presence of external impedances cannot be obtained from
simple rescaling of the bare moments already in the second moments. As a direct
consequence, we find that the cross correlation between the output terminals
can become positive due to the impedances in the circuit. We provide formulas
for the range of parameters that can cause positive cross correlations.
