§111.51-3. Short-circuit calculations for systems below 1500 kilowatts.
46 C.F.R. § 111.51-3
The following short-circuit assumptions must be made for a system with an aggregate generating capacity below 1500 kilowatts, unless detailed computations in accordance with § 111.51-4 are submitted:
The maximum short-circuit current of a direct current system must be assumed to be 10 times the aggregate normal rated generator currents plus 6 times the aggregate normal rated currents of all motors that may be in operation.
The maximum asymmetrical short-circuit current for an alternating current system must be assumed to be 10 times the aggregate normal rated generator currents plus 4 times the aggregate normal rated currents of all motors that may be in operation.
The average asymmetrical short circuit current for an alternating-current system must be assumed to be 8 1/2 times the aggregate normal rated generator currents plus 3 1/2 times the aggregate normal rated currents of all motors that may be in operation.
Notes, amendments, and revision history
Source
Source: USCG-2020-0075, 88 FR 16362, Mar. 16, 2023, unless otherwise noted.
Authority
Authority: 46 U.S.C. 3306, 3703; DHS Delegation No. 00170.1, Revision No. 01.2. Section 111.05-20 and Subpart 111.106 also issued under sec. 617, Pub. L. 111-281, 124 Stat. 2905.
Source
Source: CGD 74-125A, 47 FR 15236, Apr. 8, 1982, unless otherwise noted.