In the paper the latest statistics of middle voltage network power line failures and causes of these failures are analyzed. The paper is based on the analysis of the Latvian statistical data, but these statistical data are also compared with other countries' statistics, which is quite similar in most countries. It means that information included in the paper can be widely used in any middle voltage electricity distribution network reliability calculations and analysis all over the world. In the paper possibilities to reduce number of failures using different methods are presented and also compared quality of energy distributed through the network for two cases – when network is formed by overhead or cable lines is also compared. This paper presents possibility to improve reliability of distribution network using underground cables instead of OHL and also demonstrates that the perception that cable lines are more expensive than overhead lines is wrong. Conclusions made on the basis of OHL and cable line fault statistics analysis are of high importance for planning of reliability centred maintenance.