connector for utility-supplied ("mains") electrical power is extremely dangerous, and sometimes is called a suicide cable or widowmaker cord. Some hardware shops explicitly refuse to make or sell them when asked by customers who have mistakenly hung a string of Christmas lights backwards and wish to connect the socket end to a wall socket, or who intend to connect a generator to their home's electrical circuit in the event of a utility power outage. The exposed prongs on the live end of the cable pose serious electrical shock and fire hazards, and when improperly used in a generator setup may cause the equipment to burn out when utility power is restored. Similarly, an exposed connection on a jumper cable for a 12V automotive battery can be hazardous, because of the potentially high current and energy involved. Accidental shorting of the wire to vehicle ground can cause sparks, rapid heating, or even a battery explosion. In low-voltage use such as for data communications, electrical shock hazard is not an issue, and male or female connectors are used based on other engineering factors such as convenience of use, cost, or ease of manufacturing. For example, the common "patch cables" used for Ethernet (and the similar cords used for telephones) typically have male modular plugs on both ends, to connect to jacks on equipment or mounted in walls. An example of a design tradeoff in power connector selection is a coaxial power connector, which is usually set up so that power is fed from the female plug into the male jack (which is typically a part of the electronic device accepting the power). Although the plug is female, with a partially recessed center contact, it is still possible for casual accidental contact with a metallic object to short-circuit the power source. Depending on the design of the power adapter, it may react to a short circuit by shutting down temporarily, or instead by blowing out an internal safety fuse. In this example, the marginal reliability of the connector choice was deemed to be acceptable by the equipment designer, since the power adapter supplies low voltage that does not pose an electric shock hazard. The potential fire hazard from accidental short-circuiting is addressed by the internal safety fuse, although this requires that a failed power adapter must be completely replaced. In a different design, if the power adapter were intended to supply a voltage