The available short-circuit current must be computed—
(a)
From the aggregate contribution of all generators that can simultaneously operate in parallel;
(b)
From the largest probable motor load; and
(c)
With a three phase fault on the load terminals of the protective device.
Code of Federal Regulations
[CGD 74-125A, 47 FR 15236, Apr. 8, 1982, as amended by CGD 94-108, 61 FR 28279, June 4, 1996]