In this talk we will discuss the concept of fluctuation relations (FRs) in application to mesoscopic transport. Fluctuation relations are rigorous identities for the non-equilibrium averages of physical observables -- heat, mechanical or electrical work, etc. Starting from microscopic master equations, we will here explore the utility of this concept in the description of transport through systems of mesoscopic proportions.

Specifically, we will show how stochastic fluctuations around the rigorous averages established by FRs relate to the statistics of rare events. We will also see how FRs encode information on the basic mechanisms driving a system out of thermal equilibrium. We will illustrate these general results on the paradigm of a mesoscopic RC circuit subject to time dependent bias.