The study of old open clusters outside the solar circle can bring constraints on formation scenarios of the outer disk. In particular, accretion of dwarf galaxies has been proposed as a likely mechanism in the area. We use BVI photometry for determining fundamental parameters of the faint open cluster ESO 92-SC05. Colour-Magnitude Diagrams are compared with Padova isochrones, in order to derive age, reddening and distance. We derive a reddening E(B-V)= 0.17, and an old age of $sim$6.0 Gyr. It is one of the rare open clusters known to be older than 5 Gyr. A metallicity of Z$sim$0.004 or [M/H]$sim$-0.7 is found. The rather low metallicity suggests that this cluster might be the result of an accretion episode of a dwarf galaxy.
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