Amid growing expectations for more electric cars on U.S. roads, General Motors said last week standardized power plugs are needed considering that drivers will find outlet voltages that won’t be always the same.

GM said that regardless of the car's model, maker or outlet voltages, the vehicle's charge cord plug, should always remain same. It explains that a plug-in ecosystem is needed with commonality specially when users plug into the electrical grid.

GM has proposed a plug called SAEJ1772 saying it is helping lead not only the standardization of the plug but also how users interact with it as well as the electrical grid.

We're defining what a common electric vehicle conductive charging system architecture will look like for all major automakers in North America, but more importantly, we're working to resolve general physical, electrical and performance requirements so these systems can be manufactured for safe public use, GM said on in its blog Fastlane recently.

G.M. is hoping to launch its plug-in electric vehicle, the Chevy Volt in late 2010 with a price tag of about $40,000.