Distribution Transformer Fault Current Tables
A Reference Guide
For transformers in the downtown Network area contact a Network Design representative to obtain the fault current.
Customers should be advised that the fault current calculations were performed using infinite bus at the transformer secondary terminals.
Note: Austin Energy reserves the right to make system modifications including feed changes and transformer upgrades to maintain service without customer notification. System modifications can result in higher fault currents.
Transformer Size/Type | Fault Current (amperes) | ||
120/240 volt single-phase | 120/208 volt three-phase | 277/480 volt three-phase | |
Single-Phase Transformers | |||
1-10 kVA/1-ph | 2778 | n/a | n/a |
1-25 kVA/1-ph | 6944 | n/a | n/a |
1-50 kVA/1-ph | 13889 | n/a | n/a |
1-75 kVA/1-ph | 20833 | n/a | n/a |
1-100 kVA/1-ph | 27778 | n/a | n/a |
1-167 kVA/1-ph | 43490 | n/a | n/a |
Three-Phase Transformers | |||
75 kVA | n/a | 11566 | 5011 |
150 kVA | n/a | 23132 | 10024 |
225 kVA | n/a | 34698 | 15036 |
300 kVA | n/a | 46263 | 20047 |
500 kVA | n/a | 77106 | 33412 |
750 kVA | n/a | 39280 | 17021 |
1000 kVA | n/a | 52374 | 22695 |
1500 kVA | n/a | n/a | 34043 |
2000 kVA | n/a | n/a | 45391 |
2500 kVA | n/a | n/a | 56738 |