Electric appliance comprising modules that can be juxtaposed

Electrical bus apparatus having a plurality of plug-and-socket connectors, said electrical apparatus comprising:

• at least two juxtaposable modules, each juxtaposable module having (i) a module housing, (ii) at least one plug-and-socket connector, and (iii) at least one mating connector;
• at least one bridge element interconnected to said two juxtaposable modules to transmit electrical signals and operating voltages, said bridge element having two bridge connectors, each of said bridge connectors being connected to one of said mating connectors of said two juxtaposable modules;
• and,
• each of said module housings having at least one cylindrical recess with a mating connector disposed in said cylindrical recess, and each bridge connector having an essentially cylindrical outside sleeve with an O-shaped gasket disposed in an annular depression that is disposed about a periphery of said cylindrical outside sleeve with said O-shaped gasket under pressure contacting a gasket contact wall of said cylindrical recess.