What does SCCR stand for?

What does SCCR stand for?

Short-Circuit Current Rating
SCCR stands for Short-Circuit Current Rating, which is defined in the 2017 NEC (National Electric Code), Article 100 as: “The prospective symmetrical fault current at a nominal voltage to which an apparatus or system is able to be connected without sustaining damage exceeding defined acceptance criteria.”

How is SCCR calculated?

1. What is SCCR?
2. Determining a panel’s SCCR.
3. Step 1 – Determine the short circuit current rating of each component in the power circuit.
4. Step 2 – Determine whether feeder circuit components limit fault current.
5. Step 3 – Determine overall short circuit current ratings.

What is the SCCR of a fuse?

A short-circuit current rating (SCCR)1 is the maximum current a device or system can safely withstand for a specified time (such as 0.05 seconds), or until a specified fuse or circuit breaker opens and clears the circuit. SCCR is usually expressed in kiloamperes (kA).

What are the limiting factors of the short-circuit current?

On occurrence of a short circuit at any point in a system, the short circuit current is limited by the impedance of the system up to the point of fault.

Is AIC and SCCR the same?

Note: The difference between SCCR and AIC is that AIC applies to overcurrent protection devices only, and the SCCR applies to the entire assembled device, which may use as part of its assembly overcurrent protection devices with an AIC rating.

Does a VFD have an SCCR?

Therefore the VFD’s may have very high SCCR ratings, like 65kA or 100kA, which is primarily due to the ability of the fuse to achieve rapid quenching of any fault based energy release. With such high SCCRs it should not be a problem for our VFD panel to safely be applied to our circuit.

What is high fault SCCR?

Because the SCCR represents the highest short-circuit fault current that equipment such as industrial control panels can safely withstand, exceeding the SCCR may cause catastrophic and violent equipment and component failure.

What limits the fault current in power system?

Limitation to Fault Current: The short circuit current produced during a fault in a system is limited by the impedance of the system up to that fault point. So the impedance of the system provides a limitation to fault current up to the fault point.

What affects fault current?

Fault currents are caused by very low impedance short circuits. These may be shorts to ground or across phases. The resulting high current flow can result in overheating of equipment and conductors, excesses forces, and at times even serious arcs, blasts, and explosions.

What does 65k AIC mean?

65,000 amps
A breaker marked 22k AIC will protect anything it supplies so that the equipment never sees more than 22,000 amps of fault current. C: If a series rated combination is used it must be a tested combination identified by the manufacturer. D: A 65k AIC breaker will never allow more than 65,000 amps to flow past it.

What is AIC in circuit breaker?

Circuit Breakers. Resolution: AIC stands for “Ampere Interrupting Capacity”. This term is obsolete as the industry now refers to it as AIR or “Ampere Interruption Rating”. These refer to the interrupt rating of a breaker.