A high throw power electrodeposition system with improved rupture voltage is disclosed. The electrodepositable coating includes an active hydrogen-containing ionic resin and a gamma hydroxy urethane curing agent, such as a curing agent having the structural feature: ##STR1## The gamma hydroxy urethane curing agent can be prepared by reacting a polyisocyanate with a 1,3-polyol, and in particular with 2,2,4-trimethylpentane-1,3-diol. The composition can also include a curing agent having an alkyl urethane structural feature which can be the reaction product of a polyisocyanate and a blocking agent which is a fatty alcohol. A method for coating a conductive substrate with the above-described composition is also disclosed. The method includes passing an electric current between the conductive substrate serving as a first anode and a second anode to deposit the composition and the conductive substrate.