a short circuit ...

[bigbobbigbob]

Hi there

I only understand some basics of electrics, but hae been hearing/reading lately about a component, etc shorting to earth? what exactly does this mean? what exactly also is a short circuit, the same thing?

sorry i know it probably sounds silly, but i want to know!!!!

 

[electronicsuk]

A short circuit is, quite literally, a shorter, low resistance path that allows electrical current to flow around a circuit in ways other than intended.

Generally we refer to something as being a 'short circuit' when the fault is of a very low resistance, for example, if a line and neutral conductor somehow come directly into contact with each other. The low resistance of the short circuit allows a lot of current to flow, causing an overload.

A short to earth is essentially the same thing, but rather than becoming connected to a neutral conductor, the line conductor comes into contact with an earth wire or some other earthed apparatus or extraneous conductive part, like the metalwork of a building.

The above only works because neutral and earth (that is, both the earth conductor and the actual ground beneath your feet) are interconnected at various parts along the distribution network.

 

[GaryMo]

Line to earth fault - earth fault.
Line to neutral (or line to line) fault - short circuit.

 

[RF Lighting]

We are priveledged to have a 'celebrity' on our forum

A short circuit basically means the flow of electricity doesn't pass through the appliance as it was intended. It flows straight to neutral or earth instead of passing through the appliance and then back to neutral.

An appliance has a certain resistance. This varies depending on what the appliance is. The resistance of the appliance limits the amount of electrcity which will flow through it.

A short circuit has a low resistance, which means a large current will flow through the circuit. This will blow the fuse protecting the circuit. If the fuse were not there, the wiring would be destroyed, and quite probably catch fire.

Much metalwork in electrical circuits is connected to earth. That is a bit like a neutral wire, but not. (I won't go into the technicallities).
Metalwork is earthed incase a live wire or part were to accidentally touch it. The earth wire allows a large current to flow in the faulty circuit, which blows the fuse and automatically leaves the metalwork safe.

If the metalwork was not earthed, then a short to it would leave all the metalwork live, which could shock or kill someone.

 

[bigbobbigbob]

thanks for your help. it's been really helpful.

 

[uselessFCUK]

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[electronicsuk]

All hail the ale?

 

[Click-Sure]

Lets have a big cheer for the beer.

 

[RF Lighting]

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