TCC Curve for Circuit Breaker

[Grouch1980]

I've searched and searched through Google, but cannot find the TCC curve for a Siemens Q3100 circuit breaker. It's a 3 pole, 100 amp circuit breaker. Can someone please help?

 

[lielec11]

I have access to this curve via SKM. Would a simple PDF diagram work?

 

[Grouch1980]

I have access to this curve via SKM. Would a simple PDF diagram work?

Yes, absolutely! Thank you.

 

[lielec11]

SKM has two versions, one labelled as Rev. 4, one as Rev. 6. I'm assuming it might be related to when the breaker was manufactured but I'm not certain. Both are on the attached file for reference.

 

[Grouch1980]

Thank you again. I'll probably refer to Revision 6.

 

[Grouch1980]

I have access to this curve via SKM. Would a simple PDF diagram work?

Would you also be able to provide the graph for Siemens Q3100H? It's similar, but with an AIC rating of 22k.

 

[lielec11]

They are the same curve just different rating.

 

[Grouch1980]

They are the same curve just different rating.

So I just extend the instantanous region on the right all the way out to 22k?

 

[jim dungar]

So I just extend the instantanous region on the right all the way out to 22k?

No.

The AIC rating does not affect the TCC at all.
The AIC is about the protective device not turning into shrapnel while it is clearing a fault.

You should always extend your instantaneous region up to the fault current 'flowing through' the protective device.

 

[Grouch1980]

Hmm. I was under the impression the right most line on a circuit breaker graph is its AIC rating. So if the rating is 65k, that right most line (the vertical boundary) will be at 65k.

 

[jim dungar]

Hmm. I was under the impression the right most line on a circuit breaker graph is its AIC rating. So if the rating is 65k, that right most line (the vertical boundary) will be at 65k.

Not always.
The AIC point might be where the curve 'ends', but many different AIC ratings may actually share the same TCC.

 

[Jraef]

All of the Siemens TCCs for the QP breakers are the same regardless of size.

Finding them on Siemens website is challenging though. I found them in the past, can’t any more.

 

[lielec11]

Hmm. I was under the impression the right most line on a circuit breaker graph is its AIC rating. So if the rating is 65k, that right most line (the vertical boundary) will be at 65k.

The right (or top) most lines are the actual clearing time of the breaker or fuse. For a fuse, the left/bottom lines are when the fuse actually starts melting, and the right/top is where it fully clears the fault.

For breakers, the left/bottom is where the device physically starts to unlatch/open, and the right/top are where the breaker is actually open and clears the fault.