A junction box encloses wire splices only, without housing any outlets or switches. The most common style is the 4-inch square box (metal or heavy plastic), which offers extra volume to safely contain several cables and wire connectors. Electrical connectors join terminations in an electrical circuit to create a complete circuit. These electrical boxes are the core of electric distribution. Shape helps identify where a box is used. These boxes serve a fundamental purpose by containing electrical connections, which prevents accidental contact with live wires and, more importantly, contains any potential. Types of Electrical Power Connectors – The electrical power connections that enable the transfer of energy, come in a variety of shapes because electrical power sources can range in size from tiny batteries to massive power networks.