This week’s question is trivial but it is becoming increasingly an issue. Some standards use the term “fault current� while many other standards use the term “short circuit current� Some use the terms interchangeably.

Which term to you use / feel is appropriate?

Fault Current
Short Circuit Current
It doesn’t matter – use either one
Depends on the standard being used.

In my mind, "short circuit current" specifically refers to short circuits. In other words it is specific to bolted faults. It really would not be appropriate to refer to say arcing fault current as "short circuit current" because obviously that's not a short circuit. Whether it is appropriate to use it for ground faults is a little more debatable since it is often a "short circuit" but it almost always includes some resistance even in a solidly grounded system, and both Codes and end users always treat both kinds of ground faults (L-G and L-G-L) as different from phase faults (L-L or L-L-L). Even if the ground fault impedance is zero, the fault current is always lower in 3 phase systems because it is the line-ground voltage instead of line-line.

The term fault current is a lot more generic. It could refer to ground faults or arcing faults, or maybe even it could be referring to lightning or fault currents as a result of direct contact (electrocution). Printouts for arc flash studies from the popular power system analysis software programs for arc flash usually has a column for fault current and a different column for short circuit current.

Still there are good reasons for switching terms. In IEEE 1584 it is not concerned with determining the available fault current at all. Rather it takes this as a given from a different engineering study. So it rightly should NOT use the term short circuit current. However as a matter of clarity it might be appropriate for IEEE 1584 to indicate somewhere that this is typically the short circuit current.

Google Dictionary describes fault as: responsibility for an accident or misfortune.
Neither are very descriptive as Paul pointed out and both are used more like slang.

I voted for "Depends on the standard being used" because it depends on the subject being discussed or situation being addressed. For example, if I say the "fault current" rating of the switchboard is 65 kA, although I mean to say the switchboard was designed to withstand 65,000 amps in the event of a fault, the correct terminology used by the standard is "short-circuit current ratings" (NEC article 110.10). On the other hand, unless it is a bolted fault current situation (negligible impedance), the term "fault current" should be used for such as arcing fault and available fault currents (contains impedance) instead of the term "short circuit current". So in my opinion, although there are terms such as "short-circuit fault current" in IEEE 1584, short circuit is a fault current and all fault currents are not short circuit, except bolted fault current. In many developing countries, the word "arc flash" is not born yet, and the term "short circuit" is used to describe any fault from tripped miniature circuit breaker to devastating arc flash explosion.

I use the term SHORT CIRCUIT when I address SCCR for an industrial panel rating based on equipment design.
I use Fault Current when talking about my utility or supply

Hi Jim

Honestly I will use the 2 interchangeablely. However I do have to agree with Paul that using the short circuit current may be more applicable or appropriate. Thus comparing the bolted fault current versus the arcing fault current. Whether it be a L-L short circuit or L-G short circuit condition. Also I agree that fault current is more of a generic - household term that is used in the industry.

Lets' just call it for what it is. IEEE 1584 empirical equations rely on a database of test data that are laboratory tests where the current and arcing times are predetermined. The current used in those tests is a laboratory test current. It is not a fault...it is very much intentional. Fault currents never had any role in running the tests. In fact the current that is uses is AVAILABLE fault current. IEEE 1584 estimates arcing current from this. The source doesn't matter to the standard. It doesn't mattter if it is three phase bolted fault current estimates from a short circuit current standard or a ground fault current. All that matters is that some other standard estimates available fault current, just like the laboratory tests that it is based on.

Similarly, ASTM 1959 is agnostic about use of the estimated ATPV value. And 70E is agnostic about how all of these various standards are used together. Short circuit current standards estimate various kinds of short circuit currents (L-L-L, L-L, L-G-L, L-G), and overcurrent device standards use a given (available) short circuit current to estimate opening times and in the case of current limiting, the actual estimated short circuit current. Note that in the fuse standards available short current or just plain available current is termed "prospective current".

As end users of the standards there is definitely a learning curve to know how to string all these standards together like building blocks to arrive at a comprehensive solution. Currents are used or produced in various ways throughout these standards. Further of necessity the standards are also developed somewhat independent of each other. Although the work of the various Code correlating committees is very laudible, I don't think it would be appropriate or valuable in trying to pick one term over another. Otherwise we might have to go back and choose for instance the adjective available vs. the adjective prospective. Both mean the same thing but history and usage is in favor of both terms.

I was always taught that a "fault" is any abnormality in the distribution system. It can be a "short circuit" or an "open circuit".Therefore all shorts are faults, but not all faults are shorts. If you use the term fault you must specify the condition as well. The analogy would be all fuses are overcurrent devices, but not all overcurrent devices are fuses.

Exactly - That is also what I was first taught over 35 years ago. I brought this up because the 2018 Edition of NFPA 70E added a new definition:
Fault Current The amount of current delivered at a point on the system during a short-circuit condition.

Yet, it seems many of the major standards use the term "Short Circuit Current" Here are a few:

IEEE 551 is titled “Calculating Short-Circuit Currents in Industrial and Commercial Power Systems
IEC 60909 Short-circuit currents in three-phase a.c. systems
SCCR Short-Circuit Current Rating
NFPA® 110 Standard for Emergency and Standby Power Systems uses “Short Circuit Current� throughout
IEEE C37.09 References “Short-Circuit Current� for interrupting tests.

The list goes on….