Hanover, Germany  - A plug and socket which companies hope will become standard throughout Europe to recharge battery-powered cars was unveiled Monday at the Hanover Fair in Germany.

The plug shown to reporters by German electricity company RWE is blue, about as big as a fist and has seven pins. The 400-volt connector is intended to replace the current wide variety of household plugs used to recharge electric cars.

The Hanover Fair does not normally include any automotive products.

But companies which showcase electric motors and switchgear at the event have developed a keen interest in road vehicles following Britain's announcement of incentives of up to 5,000 pounds to purchasers of battery-powered cars beginning in 2011.

RWE, a German utility, cautioned that the plug design was simply a first step towards an official standard which would allow motorists to drive all over Europe and top up batteries without needing adapters.

"We obtained advance agreement from the 20 biggest European carmakers and energy suppliers," said Carolin Reichert, chief of the new-business unit at RWE.

The three-phase connector, able to carry up to 63 amperes of current, may allow more sophisticated future batteries to recharge in as little as an hour at car-parks, supermarkets or filling stations.

Current domestic recharging connectors using household voltage require a whole night.

So far, electric cars still suffer from a limited range and the batteries, which often cost 8,000 euros (10,550 dollars) apiece, are still not as powerful as hoped. For most private owners, the low performance and high cost is a disappointment.

But Reichert said the plug agreement was important as it gave companies an assurance there would be no costly last-minute changes if they invested money in research on more advanced cars.

Experimental fleets of e-cars in the German capital Berlin are being operated by big companies including RWE. The German government plans to invest 500 million euros in the industry, including 115 million euros to set up electricity filling stations.

London is pressing ahead even faster. On top of subsidies to car owners, it has arranged European Investment Bank (EIB) loans to two car companies, Nissan and Jaguar, to set up production lines for electric cars. (dpa)