Industrial Control Panel SCCR

[patm72]

Does a machine that has terminal blocks wired upstream of a MCCB to allow flexibility of connection in the field have a SCCR equal to that of the terminals?

As you know, terminals have a 5kA or 10kA rating at best if unprotected.

The reason for that arrangement is to have flexibility to connect the unit from underneath and avoid contractors passing the cables inside and potentially create some damage doing so. Those “upstream” terminals are enclosed in a compartment accessible from the outside of the unit, and, if needed and as mentioned above, are factory connected to the MCCB.

I wonder if they have to be considered as in the same “panel” as my other components for the SCCR. But still, they are part of the whole enclosure.

Thanks for your inputs.

 

[LionelHutz]

Yes, you need to include them in the SCCR determination.

 

[DRWeig]

Agree with Lionel. Been through this with our UL inspector a few times...

Best to you,

Goober Dave

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[patm72]

Thank you both for your inputs. Much appreciated.

 

[jraef]

And just so you know, there ARE terminal blocks with higher SCCRs now. At first, the TB mfrs had no clue, but then some discovered the issues and listed theirs at higher values so as to not lower the entire panel rating. You just have to look carefully for them and probably not just use the ones you have always used.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[patm72]

I knew this, but the problem with these so called "High Fault SCCR terminal blocks" is they still need to be protected by fuses.