New Service with existing equipment with unknown SCCR

[usher]

Hi,

We have a very old service transformer and switchboard (1950s) in one of our facilities with the following specs

ex. Transformer - 2500kVA - 13.2kV to 480V - 5.6% .
ex. Switchboard - 4000A - 480V - unknown kA rating

We are planning to replace these two just because they have reached or are close to there "end or cycle".

The new transformer is planned to match the specs the of the existing transformer and the new switchboard will be 65kA fully rated.

From the new switchboard we will be feeding couple of 400A air compressors which are about 300ft away.

Like all other piece of equipment here, these compressors are pretty old and don't have an SCCR rating.

The available short circuit current according to my calculation is about 15kA at the compressor panel with the new service.

i was wondering if someone can provide me with some insight on what are my options here? Can i just install these existing equipment with unknown SCCR to the new service? will this be a code violation?

if this would be a code violation, is changing out all the equipment with proper SCCR the best solution?

Any help would be appreciated.

Thanks

 

[electrofelon]

I probably wouldnt worry about the equipment, as in the air compressor itself. Is there any standalone electrical equipment such as panelboards or safety switches? I would want those to be rated for the AFC

 

[augie47]

Right now you are shooting in the dark. I would (a) try to find the SCCR rating of the compressors; (b) determine actual conductor size; (C) discuss actual primary available fault current with POCO and see if that could be addressed by current limiting primary fuses.
Installing reactors might be less expensive than replacing compressors.