STC Rating: 25kA, 16kA, or 18.4 kA - Advantages & Clarification

[kranth]

I want clarity on STC rating that is 25kA or 16kA or 18.4 kA.
If I want to change my Specification of 12kV Indoor Breaker from 16kA to 25kA STC rating then how can I support my self.
What are advantageous points.

Please clarify me.

 

[Greg Bernhardt]

I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?

 

[berkeman]

I want clarity on STC rating that is 25kA or 16kA or 18.4 kA.
If I want to change my Specification of 12kV Indoor Breaker from 16kA to 25kA STC rating then how can I support my self.
What are advantageous points.

Please clarify me.

Welcome to the PF.

What country are you in? Are you a licensed electrician in that country? What's an STC rating?

 

[Baluncore]

Welcome to PF.
Circuit breaker STC = Short Time Current = Short-circuit current.
Once a circuit breaker operates, due to a short circuit of the load, the CB must turn off the flowing high current quickly. The CB contacts open but draw an arc that will continue until the next change in AC load current polarity.

The STC is the extreme current that can flow in the arc while waiting for the current to reverse and the arc to extinguish. If the current is greater than the STC rating then the contact material may be sputtered against the insulator, creating a permanent conductor and an arc that reignites every cycle and destroys the CB.

http://ewh.ieee.org/r6/san_francisc...g_Capacity_and_Short_Time_Current_Ratings.pdf
http://en.wikipedia.org/wiki/Circuit_breaker#Short-circuit_current

 

[alphy]

STC rating stands for Short Time Current rating, which is a measure of the maximum amount of current a circuit breaker can safely withstand for a short period of time before tripping. The higher the STC rating, the higher the amount of current the breaker can handle without tripping.

In terms of advantages, a higher STC rating means that the breaker can handle higher levels of fault current, providing better protection for the electrical system. This can also result in longer equipment life and reduced downtime. Additionally, a higher STC rating may be required by certain codes and standards for specific applications.

If you are considering changing your specification from a 16kA to a 25kA STC rating, it is important to consult with a qualified electrical engineer to ensure that the rest of the electrical system can handle the increased fault current. This may involve upgrading other components such as cables and transformers. Additionally, it is important to consider the cost of the higher rated breaker and whether it is necessary for your specific application.

Overall, a higher STC rating can provide increased protection and reliability for your electrical system, but it is important to carefully evaluate and plan for any changes to ensure safety and efficiency.