Purpose of this paper is to provide extensive information helpful for anyone performing any experiment involving 252Cf neutron source and aiming for high precision experiments. The paper summarizes basic characteristics and fields of study using 252Cf neutron source. We show the basic characteristics of our source, precise geometry in MCNP6, isotopic content, distribution of the source in the encapsulation and possible use of encapsulation for 27Al(n,2n)26Al reaction estimation and the way of handling of the 252Cf neutron source in our laboratory. Furthermore, we prove that our source is volumetric, i.e. non-point and can be considered as an isotropic in our experimental settings. Influence of the palladium matrix density on the reaction rates is also investigated. Concerning nuclear data, we are measuring fast neutron leakage spectra in various benchmark sets including spheres of different materials. Our work extends benchmark sets to possible use of cubes, in our case graphite cube of side 30 cm. The neutron spectra are measured by stilbene scintilation detector in the energy range of 1–10 MeV in the steps of 100 keV in the distance of 100 cm from the centre of the cube. There is no significant difference between measurements performed using cube or sphere except lower cost for the cube production. The agreement between calculation using ENDF/B-VII.1 library and experimental data is not satisfactory especially in the regions around 3.5 MeV and 8 MeV. The agreement within 4% of calculation to experiment ratio for neutron leakage fluxes of pure 252Cf source validates our MCNP model for studying reaction rates and leakage fluxes in the region above 1 MeV.