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Two stateroom fires on the same American ship, and the same culprit plugged into the wall both times: an ordinary surge protector, the kind sold to keep your laptop safe.
The ship was a U.S.-flagged container ship, not a cruise ship, but what the U.S. Coast Guard’s investigators found explains a rule on almost every cruise line’s banned list. The device that protects your gadgets at home can become the fire hazard at sea.
Why Do Cruise Ships Ban Surge Protectors?
Because most household surge protectors are built for the way power is wired on land, and a ship is wired differently. The U.S. Coast Guard warned in 2013 that most of these devices “will interrupt only the hot conductor when a surge occurs.” When it trips, a surge protector at home cuts the dangerous wire. On a ship, the other wire can carry power too, so a tripped protector may still be live, and it can overheat and start a fire.
The cruise lines’ rules list the banned items without saying why. The Coast Guard’s investigation is the documented account of how these devices fail at sea, and it matches what the lines prohibit.
What Did the Coast Guard Find?
In April 2013 the Coast Guard’s Inspections and Compliance Directorate issued a Marine Safety Alert on surge protective devices, then corrected and reissued it later that month. Their text was reprinted by MarineLink (April 8) and Marine Log (April 30). The Coast Guard’s own copy of the PDF refused our requests, so we read it through those two reprints, which agree on the findings.
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Send me the deals →Here’s what the investigators traced. The surge protectors in both staterooms were plugged into a lighting circuit. A fault to ground had developed on a different circuit fed from the same distribution panel. That fault, in the alert’s words, “created an imbalance of voltage between the two power conductors supplying the SPDs which caused excessive currents, overheating, and subsequently, a fire.”
“In this instance, even if the SPDs automatically tripped as designed, only one power conductor would have been secured while the other would continue to provide power, possibly shorting to the device’s ground wire and the structure of the vessel. For shipboard applications, it is critical for a device to interrupt both power conductors.”
U.S. Coast Guard Marine Safety Alert, April 2013, via Marine Log
How Is a Ship’s Power Different From Your House?
At home, a surge protector only needs to cut one wire. In the setup the alert calls WYE, an outlet’s 120 volts sit between a single hot terminal and both the neutral and ground terminals, so cutting the hot wire kills the outlet.
Ships usually skip that earth connection on purpose. Marine Insight explains that cargo and passenger ships use an “insulated neutral,” unlike land systems. On land, a bad fault to earth trips the power off. A ship can’t afford that when the circuit runs the steering gear, radar or fire pumps, so an insulated system “allows the machinery to work with one fault across the line.” It only trips when a second fault turns up on another line.
U.S. rules for ship electrics assume such systems exist. 46 CFR 111.05-25 says each ungrounded system must have a ground detection system giving “continuous indication of circuit status to ground,” and 111.05-21 requires ground detection on the lighting system, among others.
That’s the trap for a household surge protector. The alert says a ship’s 120-volt outlets may instead be wired in a Delta setup, which has “two hot leads,” each at about 60 volts. Cut one and the other stays live. A fault somewhere else on the ship, which the ship itself is designed to keep running through, can push the voltages out of balance and overheat the strip plugged into your cabin wall.
One honest caveat: the alert was about one container ship, and it says it applies to AC systems and “may be most likely applicable to larger industrial and commercial vessels.” Cruise ships are exactly that, but we can’t tell you how any particular cabin is wired. The lines don’t publish it, and that uncertainty is the reason they ban the lot.
From One Container Ship to Your Packing List
- By April 8, 2013: The first Coast Guard alert reports the two stateroom fires and says a standard called “UL Marine 1449” addresses the problem.
- April 30, 2013: The corrected alert walks that back: “There is no official Underwriters Laboratory standard for Marine Surge Protective Devices despite numerous retailers advertising ‘UL Marine 1449.'” It adds that any surge protector aboard should be approved by trained crew, limited to one per outlet and “never daisy chained.”
- September 2024: Royal Caribbean goes further than banning surge protection and prohibits multi-plug outlets outright, Cruise Hive reported. Carnival’s John Heald replied, “we have no plans to do the same,” adding “no power strips with a surge protector are allowed.”
- Late September 2024: After complaints, Royal Caribbean clarified that it allows USB-only charging blocks, Cruise Radio reported: “multi-plug blocks on which the outputs are for USB cables.”
- November 4, 2026: We re-read seven lines’ rules for the table below. Royal Caribbean’s USB exception is still there.
The timeline matters if you’re shopping. A strip sold as “marine” or “cruise-friendly” isn’t certified to a marine surge standard, because, according to the corrected alert, no official one exists.
Which Cruise Lines Ban Surge Protectors?
Five of the seven lines we checked ban surge protectors by name. Celebrity and Norwegian don’t mention them, and the lines split on plain power strips. The wording below is quoted or closely paraphrased from each line’s own page, read on November 4, 2026.
| Line | Surge protector | Plain power strip | What else the page says |
|---|---|---|---|
| Royal Caribbean | Banned | Banned: “extension cords, power strips, multi‑plug outlets” | USB chargers allowed if “marked with a recognized U.S. or European conformity certification” |
| Carnival | Banned | Allowed, with “extension cords without surge protection” | “These items may be removed if deemed unsafe” |
| Princess | Banned on strips and multi-plug boxes; a surge-protected extension cord may pass inspection | Allowed after “inspection/tests from the onboard electrical department” | Hazardous devices removed and returned on the last day |
| Holland America | Banned on strips and multi-plug boxes | Not named | Same main list as Princess, without its inspection footnote |
| Celebrity | Not named separately | Not named; “Electrical Extension Cords” banned | CPAP users: ask 30 days ahead for an extension cord |
| Norwegian | Not named | Not named | Lists transformers as prohibited; security may confiscate anything it sees as a threat |
| Disney | Banned | Banned, with “multi-plugs and surge protectors” | Confiscation delays your luggage “until late evening on embarkation day” |
For every line’s wider banned list, from irons to camouflage, see our free packing checklist.
How to Charge Everything Without One
- Pack a multi-port USB wall charger with a U.S. or European safety certification mark printed on it. That’s the exception Royal Caribbean names outright.
- Check the strip itself before you pack it. If the box or label mentions surge protection or a joule rating, it’s a surge protector. Leave it at home.
- On Carnival or Princess, a plain strip can come, but Carnival can still remove it and Princess wants its electricians to test it. On Royal Caribbean and Disney, leave it at home.
- Use longer cables, not more outlets. A longer charging cable lets one outlet reach the bed, with nothing plugged in between.
- Don’t pack it in your checked bag and hope. Royal Caribbean says banned items can be confiscated at the terminal or onboard, and Disney says a find in your luggage holds that bag back until late evening on embarkation day.
Quick Answers
What if my CPAP needs an extension cord?
Ask the line to supply one. Royal Caribbean’s special needs page says that for a CPAP or BiPAP, “distilled water and an extension cord will be provided in the stateroom,” and asks for the request no later than 30 days before sailing. With its online form down, it says to email [email protected]. Celebrity asks CPAP users to tell it at least 30 days ahead if they need a cord.
Are cruise cabin outlets 110 or 220 volts?
Often both. Princess says its staterooms have 110V and 220V outlets, and that power may run through a keycard switch, so the outlets may only work while your card is in its slot. Check your own ship before you pack adapters.
Do I get a confiscated strip back?
It depends on the line. Princess says hazardous devices are returned on the last day of the cruise. Royal Caribbean says only the items it marks on its list, such as knives and tools, “may be retained by Security for the duration of the cruise and returned.” Its electrical items aren’t marked. Don’t count on it, and don’t pack one you’d miss.
Cruise Chaos earns nothing from cruise lines, travel agents or booking links. Every fact here links to where we read it, and we read each line’s rules directly on November 4, 2026. We are not electricians, and nothing here is electrical advice for your ship. If a rule has changed, tell us and we’ll correct it.
Coming up on Cruise Chaos: what to pack for a cruise to Alaska in June.
Keep Reading
- Free Checklist PDF: What to Pack for a Cruise, Checked Against 8 Lines’ Banned Lists
- Cruise Packing Don’ts Every Traveler Should Know
- What to Expect on Cruise Embarkation Day: Cabins, Lunch and Luggage
Sources
- Marine Log: USCG issues updated safety alert on surge protectors (April 30, 2013; full text of the corrected Coast Guard alert)
- MarineLink: Surge Protective Devices Onboard Vessels (April 8, 2013; text of the first Coast Guard alert)
- Marine Insight: How Ships are Protected from Lightning, Ships Earthing System (2021, updated 2024)
- 46 CFR 111.05-25, Ungrounded systems and 46 CFR 111.05-21, Ground detection (Cornell LII, read November 4, 2026)
- Royal Caribbean: Prohibited items onboard policy and Guest special needs (read November 4, 2026)
- Carnival: Prohibited items (read November 4, 2026)
- Princess Cruises: Pre-cruise FAQs (read November 4, 2026)
- Holland America: Prohibited items (read November 4, 2026)
- Celebrity Cruises: Prepare FAQs (read November 4, 2026)
- Norwegian Cruise Line: What can’t I bring on board? (read November 4, 2026)
- Disney Cruise Line: Prohibited items (read November 4, 2026)
- Cruise Hive: Carnival Won’t Join in on Controversial Royal Caribbean Ban (September 24, 2024)
- Cruise Radio: Royal Caribbean clarifies which travel adapters are allowed on its cruise ships (September 30, 2024)
