June 13, 2025
As mentioned in my previous post, the return of Home Free to Europe means that my electrical connections need to be ‘updated’ or, perhaps more accurately, returned to the way they were before I left this continent. This post is really about me documenting the wiring so that I don’t have to take things apart again to figure out what I did. The rest is commentary for others with some warnings and caveats to prevent big errors.
Having moved the boat to the US in 2019 I changed the wiring once (James Knight at YachtTech did this work) and then due to a problem with a dock connection in 2022, I switched to a SmartPlug on the boat side. These changes gave me a bit of an understanding for the wiring on the dock pedestals as well as my boat side. Overall, engineers have made plugging a boat into a dock incredibly simple despite it being a very complicated subject. Also, in case other owners are interested in using the information I am providing here, don’t rely on it. I am not an electrician and getting things wrong can cause significant damage to your boat, a pedestal, or even a marina in case of a fire.
My limited understanding is that there are two common connections in North America (excluding a regular plug). They are 30A and 50A round plugs (Marinco is the major supplier for these).
Home Free can use a lot of power so it has 50A inlets on the boat side. There are two of them, one for house power (battery charging, running appliances, etc.) and one for Air Conditioning/Heating.
I swapped out one of the Marinco 50A sockets on the boat side for a SmartPlug, which is safer and easier to use, but they are not common, and much harder to find outside of North America.
Since it is difficult to recreate all of the diagrams with my tools at hand, I will use my hand drawn work. Here is the wiring:
This is not a thorough description, so again I hope its helpful to others, but the US Cable assumes there are two 110 or 115V hot lines and a Neutral line. Technically there should be a 4th wire (ground), but the EU system is simply a 3 wire system. The SmartPlug 50A is a 4 wire system, so we ignore wire 4 (top of plug).
Notably, ignoring the fourth wire breaks rules and can be dangerous. I don’t mean to diminish the dangers here but so much with electricity is dangerous, that I am ignoring that warning. Just be prepared to blow a fuse if something is wrong.
The two hot legs in the NA 50A connection are connected to pins 1 and 3 and neutral is connected to pin 2. If your boat side and shoreside look like these, things should work.
Now switching to Europe, they have a different system. They use 16A and 32A cables, all three wire and the diagram is below.
A couple of minor notes about the EU system. The tab on the housing means you can see where to line up the plug, and you can’t plug it in the wrong way. Also, there is an integrated cover (not shown well here) on the female ends to protect the receivers for the pins. The integrated cover also locks onto the male side if the plug is properly inserted. This prevents the plugs being inadvertently knocked off or not fully inserted/connected. It’s a nice system.
In that setup, the larger pin is Ground (E or Earth in their naming) and the next pin clockwise is the live pin (L which carries the current to the system) and the last pin is the Neutral (N which completes the circuit). Here is a diagram.
Notably, that Ground pin (which provides a path for current when there is a failure somewhere in the circuit) is the wire missing for my North American wiring.
Another key point that is reviewed in the Nigel Calder article below, is that wire size matters a lot and if your boat is not designed for 230V, the wire sizes may not carry the loads needed to run appliances. (A draw of 5A at 230V is equivalent to 10A at 115V and if this extra (doubled) load is carried on the same wire size, those wires could overheat/melt and cause a fire)
Nigel Calder is one of the best known authors on marine repairs. He has a much more concise, yet comprehensive overview of considerations for switching between the North American and European electrical grids. You can find it here (click this).
On a final note, the boat was well stocked with conversion connectors when I purchased Home Free. Many of those connectors have sat in my anchor locker/well for the past five years where there is moisture and salt residue. I pulled out a 16A to 32A connector and am using it now, but what a shock! Literally. Probably due to the cable degrading, when I went to plug the 16A end of the cable converter into the shore side, I got a nasty shock (and I did it three times because I like to live dangerously). The second and third time, I was wearing gloves and rubber soled shoes, but one of my next projects is building a new 16-32A conversion cable and hopefully the next time I plug one in it won’t leave me so energized. Always be careful with electricity. It can kill you.