how protections differ from each other????

(Not sure, I am helping somebody's homework. Dear Guest, please ensure)

(1) For 'the difference between simple earth fault, stand by earth fault, sensitive earth fault and restricted earth fault', see this link from another forum:

http://cr4.globalspec.com/thread/44486

(2) For 'how do overcurrent, short ckt and over load differ', the answer is here:

Over Current is more generic term. It is categorized as Overload Current and Short Circuit Current.

Over Load Current: The term overload is applicable mostly for motor loads. It is generally the current when motor is overloaded by some reason. Overload can be sustained for certain period of time. There should be separate overload protection in this case.

Short Circuit Current: It is due to the fault (line to line, line to ground) in the circuit and applies to all type of circuit. The circuit should be isolated immediately. Motor starter should have short circuit current protection in addition to overload current protection.

I also answered it in http://cr4.globalspec.com/thread/34521

- MS

Thx for your reply. and sorry for my very late reply. still my question remains unclear.

"In any electrical fault condition whether earth fault, short ckt or over load, either current or voltage will increase or decrease or may be both. Than how all the above mentioned faults differ."