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Serving North Texas Since 1937

Transformer Fault Current Ranges

This calculation assumes an infinite bus, and the values provided are calculated at the secondary terminals of the transformer. For additional fault information, please contact systemplanning@coserv.com.

Note: CoServ 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.

  Service
Phasing: 1
Voltage: 120/240 240/480
kVA Rating Minimum Available
Fault (A)
Maximum Available
Fault ( A)
Minimum Available
Fault (A)
Maximum Available
Fault ( A)
10 1,042 2,778 521 1,389
15 1,563 4,167 781 2,083
25 2,604 6,944 1,302 3,472
37.5 3,906 10,417 1,953 5,208
50 5,208 13,889 2,604 6,944
75 7,813 20,833 3,906 10,417
100 10,417 27,778 5,208 13,889
167 17,181 34,792 8,591 17,396
250 16,855 52,083 8,428 26,042

  Service
Phasing: 3
Voltage: 120/208 277/480
kVA Rating Minimum Available
Fault (A)
Maximum Available
Fault ( A)
Minimum Available
Fault (A)
Maximum Available
Fault ( A)
75 3,621 7,710 1,569 3,341
112.5 5,431 10,073 2,353 4,365
150 7,241 13,431 3,138 5,820
225 10,862 20,146 4,707 8,730
300 14,482 26,862 6,276 11,640
500 24,137 31,905 10,459 13,825
750 33,868 39,131 14,597 16,957
1000     19,463 22,609
1500     29,194 33,914
2000     38,926 45,219
2500     48,657 56,523