In document ISO 10303-226, a fault is defined as an abnormal condition or defect at the component, equipment, or sub-system level which may lead to a

failure Failure is the state or condition of not meeting a desirable or intended objective (goal), objective, and may be viewed as the opposite of Success (concept), success. The criteria for failure depends on context, and may be relative to a parti ...

. In telecommunications, according to the Federal Standard 1037C of the United States, the term ''fault'' has the following meanings: #An accidental condition that causes a functional unit to fail to perform its required function. See . #A defect that causes a reproducible or catastrophic malfunction. A malfunction is considered reproducible if it occurs consistently under the same circumstances. See . # In power systems, an unintentional short circuit, or partial short circuit, between energized

conductor Conductor or conduction may refer to: Music * Conductor (music), a person who leads a musical ensemble, such as an orchestra. * ''Conductor'' (album), an album by indie rock band The Comas * Conduction, a type of structured free improvisation ...

s or between an energized conductor and

ground Ground may refer to: Geology * Land, the surface of the Earth not covered by water * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical c ...

. A distinction can be made between symmetric and

asymmetric fault In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which a live wire touches a neutral or ground wire. An open-circuit fault occurs if a circuit is interrupted by a f ...

s. See Fault (power engineering).

Random fault

A random fault is a fault that occurs as a result of wear or other

deterioration Deterioration may refer to: * Worsening of health * Physical wear See also * Decadence (disambiguation) * Degeneracy (disambiguation) * ''Deteriorata'', a parody of ''Desiderata'' * Decay * Decline Decline may refer to: *Decadence, involves a ...

. Whereas the time of a particular occurrence of such a fault cannot be determined, the rate at which such faults occur within the equipment population on average can be predicted with accuracy. Manufacturers will often accept random faults as a risk if the chances are virtually negligible. A fault can happen in virtually any object or appliance, most common with electronics and machinery. For example, an Xbox 360 console will deteriorate over time due to dust buildup in the fans. This will cause the Xbox to overheat, cause an error, and shut the console down.

Systematic fault

Systematic faults are often a result of an error in the specification of the equipment and therefore affect all examples of that type. Such faults can remain undetected for years, until conditions conduce to create the

. Given the same circumstances, each and every example of the equipment would fail identically at that time. Failures in hardware can be caused by random faults or systematic faults, but failures in software are always systematic.