IEC 60364-5-52:2009 deals with the selection and erection of wiring systems. This third edition cancels and replaces the second edition, published in 2001, and constitutes a technical revision. The main changes with respect to the previous edition are as follows: - Subclause 521.4 introduces minor changes with regard to busbar trunking systems and powertrack systems. - Subclause 523.6 introduces minor changes with regard to the sizing of cables where harmonic currents are present. - A new sublause 523.9 concerning single-core cables with a metallic covering has been introduced. - Clause 525 introduces changes in the maximum value of voltage drop permitted between the origin of the consumer' s installation and the equipment which should not be greater than that given in the relevant annex. - Clause 526 introduces minor changes to electrical connections including additional exceptions for inspection of connections and additional notes. - Clause 528 introduces additional requirements with regard to proximity of underground power and telecommunication cables. - Clause 529 introduces minor changes to selection and erection of wiring systems in relation to maintainability, including cleaning.