Will the Shore Power on My European-Built Boat Work OK?

The differences between European and U.S. voltages mean that wire-gauge sizes and operating frequencies for equipment that runs on shore power need to be carefully addressed.

6th November 2013.
By Ed Sherman

Question: I just took delivery of a new boat made in Europe. It’s equipped with a battery charger, air-conditioning and refrigeration, a microwave oven, and an electric water heater. The boat has some electrical outlets that are the familiar type we see here in the US.

It's not so much the plugs and sockets that are a worry, but wiring originally sized for 230 volts will be only half the correct gauge for 115 volts in the U.S.

It’s not so much the plugs and sockets that are a worry, but wiring originally sized for 230 volts will be only half the correct gauge for 115 volts in the U.S.

But, while looking around in some of the equipment lockers the other day I found the plug and cord setup you see here in my photo. The plug shown is the power feed for the water heater.

Both the plug and the socket it fits into look like setups I’ve seen when traveling overseas, but there is a label on the side of the socket assembly that says “115 volts.” I also noted the diameter of the power feed cord to the heater seems really small compared to other 115-volt extension cords and the like I’m familiar with here in the US. What’s up with this, and will my appliances that use shore power work OK on my new boat with this arrangement?

Answer: There are a few things you need to find out to be sure all is well with your boat. First of all, wire gauge sizing is a concern. Your observation that the power cord seems small compared to what you are used to is quite valid. As you are probably aware, Europeans use 230-volt equipment, which will run just fine with wire that is approximately 50-percent smaller than the wire and cable we use to run our 110- 120-volt appliances here in the US. This is all possible due to the fact that when voltages are twice as high, amperage (current) draws for a given appliance will also be halved, and therefore the use of smaller power conductors works out just fine. From what I see in your photo, it looks like the builder did not take the need for heavier gauge wire into account when they converted things for 115-volt use. The plug and socket assembly shouldn’t be a concern here, but the undersized wire is.

Besides small wire, the matter of appliance voltage operating range and frequency is of concern here. You need to confirm that things like your battery charger, microwave oven, and refrigeration system components are rated for dual-frequency operation. European gear runs at 50 Hz and here in the US we run at 60 Hz. As already stated, we run at 115 volts, and the same gear in Europe runs at 230 volts.

The bottom line here is that to properly convert a European shore power system to US means up sizing all of the AC wiring, not just replacing a plug assembly here and there — so you also need to confirm that this has been done. Even though your gear may seem to be working just fine with smaller than normal cable supplying it, this could become a problem in the long term as equipment ages and voltage drop to equipment becomes more likely — and more worrisome in terms of potential overheating issues.


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About the author:

Ed Sherman

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Ed Sherman is a regular contributor to boats.com, as well as to Professional Boatbuilder and Cruising World, where he previously was electronics editor. He also is the curriculum director for the American Boat and Yacht Council. Previously, Ed was chairman of the Marine Technology Department at the New England Institute of Technology. Ed’s blog posts appear courtesy of his website, EdsBoatTips.
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http://www.EdsBoatTips.com

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