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SKM 208V calculated sc current too low. Any ideas?

SKM 208V calculated sc current too low. Any ideas?

SKM 208V calculated sc current too low. Any ideas?

(OP)
Hello and help.
My sc report results don't make sense. I have a 3000A 480/277V building with utiltiy reporting 51k AIC. For some reason all the 208V fault currents are calcuulated in the 500A range. When I model the 208 v portion separately, the results are in the 5000A range. Any ideas whate my glitch is??? Thanks!

RE: SKM 208V calculated sc current too low. Any ideas?

Garbage in, garbage out?  What size transformer do you have between the 480 and the 208?  What is the transformer impedance?  I haven't regularly used SKM for the past 3 years and not at all for the past 1.5, but up until 3 years ago I used it extensively and GIGO always turned out to be the explanation for weird results in routine calculations.

RE: SKM 208V calculated sc current too low. Any ideas?

(OP)
Looks like some glitch -
If I first add a new 208V bus, the Isc is reasonable -5k ish. When I rerun, it drops to .5 ish. Hmmm
Can't revert.

RE: SKM 208V calculated sc current too low. Any ideas?

Send it to SKM, they've always been helpful.

RE: SKM 208V calculated sc current too low. Any ideas?

Just curious. What is your transformer capacity, KVA? Your transformer impedance? I assume that you are having a 480-208Y/120V step down transformer and you intend to calculate the 3Phase 208VAC short circuit current.

RE: SKM 208V calculated sc current too low. Any ideas?

(OP)
OK I had a corrupted SKM project... I "merged" the existing project into a "blank" one and the new results look great! thanks for the advice. This actually got me revisisting transformer technology and conceps which should happen every once in a while! (There are some interesting transformer discussions this site.)
Thanks to all for ideas ans advice.
Best,

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