"EHWAZ is a professional software solution dedicated to the sizing, analysis and optimization of electrical wire harnesses in aeronautic context. Starting from an electrical harness definition (logical and wire harness CAD-info and equipment definition), the tool checks whether harnesses comply with user-defined business rules. The harness definitions are then used to create a physical electro-thermal model (Modelica and/or C based). These models are used to simulate the transient electro-thermal phenomena in function of A/C missions and the location of the harness in the A/C. Automated post processing build map of heat flow from the harness to its environment (by branch & by A/C zone), and global results for the harness are reported by wire and by branch: weight, temperature, voltage drop, heat flow. Additionally, the electrical simulation allows plotting the current evolution, temperature and the electrical resistance over time and by wire. The voltage drop includes the current path return with respect to the A/C technology (metal, composite or hybrid). The simulation results are linked to and benchmarked with the professional rules (user-defined by integrator and/or supplier). Eventually, an optimization process is included to help the harness designer sizing and selecting the right wire. The optimization technology takes into account the multiple constraints, discrete standard aeronautical wire database. The optimization wants to achieve minimal harness weight & costs versus an electro-thermal safe, reliable & robust harness. The output of the optimization is an XML file describing the optimized harness selection in term of wire type and gauge. Besides wires optimization, the connectors are challenged to find a lighter global harness. The mechanism of professional rules extension associated with the formalism chosen for models creation offers the possibility to further extend the capacity of the tool."