I don't know a lot about electricity, but I know that on earth we ground our outlets, computers, etc. Do they have a means of grounding electricity in space? Are electrical systems more dangerous on spacecraft?
In electrical engineering, earthing or grounding means literally to make an electrical connection between the ground and a metal part. In practice this is usually done by connecting to the ground pin of an electrical socket, which is itself connected to ground. In permanent installations it can also be done by wiring to a piece of grounded metal, most often a water pipe. The main reason for doing this is safety. If a live wire touches a metal part such as the casing of a washing machine, it will become live or hot. If you were to touch it you would get an electric shock. By grounding the metal part, if a live wire touches it the current will flow through the metal part to the ground. This will usually cause a fuse to blow or a circuit breaker to trip, thereby isolating the supply and protecting the user. Despite what a previous answerer said, the ground is not part of the circuit of the electrical supply to your house. A separate conductor, the neutral, serves that purpose. Current only flows into the ground during a fault condition like the one I described above. In electronics, the term ground is often used to mean a part of the circuit which has zero volts on it, and may be used as a return path for electric currents in the circuit and/or a screen against electromagnetic interference. For instance, an electronic engineer may say that a part of the circuit is at 5 volts above ground.
We do not ground all electrical equipment. Much of it is double insulated. Grounding simply connects the chassis to Earth, so that if there is an electrical fault that makes the chassis live this is short to Earth and a person, who we might expect to be standing on Earth and not hovering, will hence be at the same potential as the chassis. The actual circuit is not grounded - its return path conencts to neutral. Precisely the same principle can be used in space, but in light of the fact that people in space may actually be floating, double insulation is safer.
