46 CFR § 111.51-4 - Short-circuit calculations for systems 1500 kilowatts or above.

---
identifier: "/us/cfr/t46/s111.51-4"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 111.51-4 - Short-circuit calculations for systems 1500 kilowatts or above."
title_number: 46
title_name: "Shipping"
section_number: "111.51-4"
section_name: "Short-circuit calculations for systems 1500 kilowatts or above."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "J"
subchapter_name: "ELECTRICAL ENGINEERING"
part_number: "111"
part_name: "ELECTRIC SYSTEMS—GENERAL REQUIREMENTS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
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."
regulatory_source: "CGD 74-125A, 47 FR 15236, Apr. 8, 1982, unless otherwise noted."
cfr_part: "111"
---


# 111.51-4 Short-circuit calculations for systems 1500 kilowatts or above.

Short-circuit calculations must be submitted for systems with an aggregate generating capacity of 1500 kilowatts or more by utilizing one of the following methods:

(a) Exact calculations using actual impedance and reactance values of system components.

(b) Estimated calculations using IEC 61363-1:1998 for AC systems and IEC 61660-1:1997 for DC systems (both incorporated by reference; see § 110.10-1 of this subchapter).

(c) The estimated calculations using a commercially established analysis procedure for utility or industrial applications.