Short Circuits
occurs when two conductors adjacent to each other lose so much insulation that a current flows directly between them.
May cause wiring to get quite hot and cause a fire within the wall
Especially dangerous because it may spread for some time before being detected.
Shutoff Devices
Fuses = a soft metal link in glass plug or fiber cartridge. rated for a certain current flow, if current exceeds rating then the link will melt breaking the circuit.
Requires replacing when blown, largest glass plug fuse is 30 amps, cartridge fuses can be rated higher.
Circuit breakers = Device that automatically disconnects a circuit when a current is excessive.
May be reset after trouble is found a repaired
Can be used to shut off an are or circuit to be worked on.
more expensive than fuses but are most used, simple, no replacement required, low maintenance cost.
ground fault (circuit) interrupter (GFI or GFCI) = detects a continual current lost to ground, even after power is shut off.
required on any circuit of 15 or 20 amps which serves a bathroom, garage or outdoor area and temporary construction site circuits.
Large high voltage circuits such as 480/277 volt 1000 amps are required to have them.
Grounding
Basic safety precaution, ground wire is fastened to an element which provides path directly to the ground.
Dissipates any electric current with little or no resistance averting possible damage or injury.
Appliances are often grounded by their metal casings
Ground wires are covered with green insulation or even left bare.
typically connected to a cold water pipe providing a path under ground.
This would be useful for home owners who are having trouble or are not familiar with the electrical safety terms. Remember not to tinker with your home's electrical system unless you really know how to. The confidence to tinker stuff isn't going to be enough. Ask the experts if you want to know more about it.
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