46 CFR 143.400: General electrical system requirements on towing vessels
Last reviewed: October 14, 2026
This section sets general rules for electrical systems and equipment on towing vessels. Systems must work properly and limit failures, fire hazards and shock hazards. The section also covers power capacity, markings, labels, connections, protection, enclosures, bulkhead penetrations and plugs.
What it says
Electrical systems and equipment must function properly and minimize system failures and fire and shock hazards.
46 CFR 143.400(a)“Electrical systems and equipment must function properly and minimize system failures and fire and shock hazards.”
Installed electrical power sources must be capable of carrying the electrical load of the towing vessel under normal operating conditions.
46 CFR 143.400(b)“Installed electrical power source(s) must be capable of carrying the electrical load of the towing vessel under normal operating conditions.”
Electrical equipment must be marked with its respective current and voltage ratings.
46 CFR 143.400(c)“Electrical equipment must be marked with its respective current and voltage ratings.”
Individual circuit breakers on switchboards and distribution panels must be labeled with a description of the loads they serve.
46 CFR 143.400(d)“Individual circuit breakers on switchboards and distribution panels must be labeled with a description of the loads they serve.”
Electrical connections must be suitably installed to prevent them from coming loose through vibration or accidental contact.
46 CFR 143.400(e)“Electrical connections must be suitably installed to prevent them from coming loose through vibration or accidental contact.”
Electrical equipment and electrical cables must be suitably protected from wet and corrosive environments.
46 CFR 143.400(f)“Electrical equipment and electrical cables must be suitably protected from wet and corrosive environments.”
Electrical components that pose an electrical hazard must be in an enclosure.
46 CFR 143.400(g)“Electrical components that pose an electrical hazard must be in an enclosure.”
Electrical conductors passing through watertight bulkheads must be installed so that the bulkhead remains watertight.
46 CFR 143.400(h)“Electrical conductors passing though watertight bulkheads must be installed so that the bulkhead remains watertight.”
Common questions
What must be marked on electrical equipment on a towing vessel?
Electrical equipment must be marked with its respective current and voltage ratings.
“Electrical equipment must be marked with its respective current and voltage ratings.”
How must circuit breakers be labeled on towing vessel switchboards?
Individual circuit breakers on switchboards and distribution panels must be labeled with a description of the loads they serve.
“Individual circuit breakers on switchboards and distribution panels must be labeled with a description of the loads they serve.”
Which electrical components must be in an enclosure?
Electrical components that pose an electrical hazard must be in an enclosure.
“Electrical components that pose an electrical hazard must be in an enclosure.”
What must flexible cable plugs and socket outlets be designed to do?
The connections of flexible cable plugs and socket outlets must be designed to prevent unintended separation.
“The connections of flexible cable plugs and socket outlets must be designed to prevent unintended separation.”
The text of 46 CFR 143.400
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Electrical systems, general
(a) Electrical systems and equipment must function properly and minimize system failures and fire and shock hazards.
(b) Installed electrical power source(s) must be capable of carrying the electrical load of the towing vessel under normal operating conditions.
(c) Electrical equipment must be marked with its respective current and voltage ratings.
(d) Individual circuit breakers on switchboards and distribution panels must be labeled with a description of the loads they serve.
(e) Electrical connections must be suitably installed to prevent them from coming loose through vibration or accidental contact.
(f) Electrical equipment and electrical cables must be suitably protected from wet and corrosive environments.
(g) Electrical components that pose an electrical hazard must be in an enclosure.
(h) Electrical conductors passing though watertight bulkheads must be installed so that the bulkhead remains watertight.
(i) The connections of flexible cable plugs and socket outlets must be designed to prevent unintended separation.
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.