# 46 C.F.R. § 111.10-9 (2026): Ship's service supply transformers; two required

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_9

## Section

- **Citation:** 46 C.F.R. § 111.10-9 (2026)
- **Heading:** Ship's service supply transformers; two required
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 46 CFR: Shipping / Chapter I: COAST GUARD, DEPARTMENT OF HOMELAND SECURITY / Part 111: ELECTRIC SYSTEMS—GENERAL REQUIREMENTS / Subpart 111.10: Subpart 111.10—Power Supply / § 111.10-9: § 111.10-9   Ship's service supply transformers › two required.

## Text

If transformers are used to supply the ship's service distribution system required by this subpart for ships and mobile offshore drilling units, there must be at least two installed, independent power transformers. With the largest transformer out of service, the capacity of the remaining units must be sufficient to supply the ship service loads.
Note to § 111.10-9:
A ship's service supply system would consist of transformers, overcurrent protection devices, and cables, and would normally be located in the system between a medium voltage bus and a low voltage ship's service switchboard. It is not the intent, nor is it required, that transformers fed by the ship's service switchboard, such as 480/120 transformers, be duplicated.
[CGD 94-108, 61 FR 28277, June 4, 1996; 61 FR 33045, June 26, 1996; USCG-2020-0075, 88 FR 16360, Mar. 16, 2023]

## Nearby sections

- [46 C.F.R. § 111.10-3 (2026) § 111.10-3   Two generating sources.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_3.md)
- [46 C.F.R. § 111.10-4 (2026) § 111.10-4   Power requirements, generating sources.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_4.md)
- [46 C.F.R. § 111.10-5 (2026) § 111.10-5   Multiple energy sources.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_5.md)
- [46 C.F.R. § 111.10-7 (2026) § 111.10-7   Dead ship.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_7.md)
- [46 C.F.R. § 111.10-9 (2026) § 111.10-9   Ship's service supply transformers; two required.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_9.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T46_P111_S111_10_9. Check the current official text before relying on it. Not legal advice.