  We consider wide ballistic microcontacts with electron-electron scattering in
the leads and calculate electric noise and nonlinear conductance in them. Due
to a restricted geometry the collisions of electrons result in a shot noise
even though they conserve the total momentum of electrons. We obtain the noise
and the conductivity for arbitrary relations between voltage V and temperature
T. The positive inelastic correction to the Sharvin conductance is proportional
to T at low voltages eV << T, and to |V| at high voltages. At low voltages the
noise is defined by the Nyquist relation and at high voltages the noise is
related with the inelastic correction to the current by the Shottky formula
S_{in} = 2eI_{in}.
