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In this paper we present an experimental work on a new laboratory model for flashover studies. Two- surfaces polluted disk insulator model, This model looks like a real outdoor insulator with respecting its shape and pollution. The experimental results of this model and their analysis were performed in two groups: The first is the measure of pollution resistance between the ground electrode and a static discharge for many discharge positions; the second is the measure of critical current and critical voltage according to the position of the discharge starting point. A comparison with the case of point to point gap reveals that the electric field in the air in the vicinity of the electrolyte surface is the responsible of the discharge elongation, and the critical conditions of flashover are the weakest initial electric conditions necessary to create this field distribution.