Fault Current vs Short Circuit Current

Fault current - it is the current exceeding the equipment current rating e.g. motor rated 14A & then more than this will be the fault current.

Short Ckt current - it is the maximum current which can flow whem the equipment is short circuited & it can withstand..above this the current will damage the equipment.

do you mean starting current is a fault current because at starting all device having a cold resistance hence starting current is always more than rated current. short ckt is one type of fault. pls clarify.

fault current is the current into a fault be it phase to phase, phase to neutral or phase to ground / earth. In order to calculate it I = V/R you need to know the resistance of the external supply as well as that of your installation. Your supplier should provide information on how much current they would deliver in the event of a fault. You should ensure that the breaking capacity of your protective devices is large enough to handle this. A big fault with a high fault current will clear a fault quickly if your installation is good. To answer your question they are the same, but prospective is the likely amount that would flow in the real world. (not I = 230 / 0)

A fault current is a current which takes the wrong path: instead of using the normal cunductors you installed it starts using ground and humans to find its way back to the generator.

A short circuit current is a current which uses the normal conductors but found a shorter way to get back, resulting in much higher currents than those which have been assumed when designing the the system.

Both are a problem: the first can kill you the second can damage your wiring resulting in fire and loss of property.

The problem is indeed the size of these currents: fault currents have typically the size of mA, short circuit currents can be smaller than the startup current of a system.

The solution is to use proper protective devices as the fuse and RCD. Both need to be properly selected to match the installation behind.

If you don't have the knowledge then don't do it, go back to school and get the knowledge behind AC and installation techniques. Electricity is way to dangerous to mess with. If you really need to define a system ask a decent engineering firm to do it for you.

Trial and error is no solution in this domain of engineering.

spot on nice to see a very precise answer, some of the others are a bit off the mark

Gwen, you have the best and most accurate answer up to now, all before you did not have a fully thought out and correct answer!

Well put!

I will read the ones below you after posting this!

Prospective fault current and short circuit current are the same thing.

COmment to remember about fault current, it is not the engineer's fault!!!

...no wonder you have a name like Blitz, but that was an incorrect answer.

Read Gwen's answer, a little higher up....that is fully correct.

"The above link will give you some help to understand the concept."

Understand what exactly? That I should buy this software! It has not explained anything other than that they are a commercial setup trying to sell us something. I do not think this forum is for plugging products UNLESS the generator of the discussion specifically asked for it.

Sorry but that is my 2 cents worth of freely given opinion.

result

A fault current can be due to either current being more or less than the normal rated current. Short cct can be a desirable path of low resistance. But they are not the same.