Q: Your boat isn’t fitted with a shore power system and you would like to add one. Is this something you can do yourself, or should you contact a yard familiar with electrical work?
A: It certainly is possible to do the work yourself, providing you are competent with tools and understand the basics of what you are trying to achieve. First and foremost it is important to remember that main electricity, unlike the 12-volt systems on your boat, can kill and must be treated with the utmost respect.
All wiring should comply with American Boat and Yacht Council codes, which set guidelines as to how the wiring installation should be completed and maintained. Although it isn’t possible to go into great detail here, a brief outline of the way in which I would go about installing a shore power system will hopefully point you in the right direction and help you decide if this is a job for you or a yard.
The first thing I suggest doing when contemplating this type of installation is to make a sketch of the boat, and plan out where power outlets should be positioned. You may also like to connect a water heater or other devices that will be wired into a cir- cuit directly — in other words, those that are not plugged into a receptacle on board — so make a note of where these go, too.
Locate the best position for the AC distribution panel. This often is near the DC panel on many boats, but it doesn’t have to be. Wherever it is placed, it has to be electrically isolated from the 12-volt circuits, so it makes sense to have the panel mounted in its own compartment where possible.
Choose a panel that has more circuit breakers than you need so you will have the ability to add extra circuits without changing the panel. Blue Sea makes some good panels, and these incorporate ammeters and voltmeters so you can see at a glance how much power you are consuming.
Most marinas supply power to boat owners from 30-amp three-pin locking receptacles. You will need to buy a suitable shore-power cord with a male and female end. The male end is plugged into the dockside power, and the female end into a waterproof 30 amp socket on the outside of the boat, typically on the side of the cabin. From here the power is wired into the aforementioned distri- bution panel, and from there to the various circuits, such as the water heater, air conditioner and sockets.
This all sounds quite easy, but the fact that the boat is sitting in water raises a few problems. All sockets should be protected by ground fault circuit interrupters to minimize the chance of shock hazard. If the length of cable between the socket on the boat and the panel is greater than 10 feet you will have to install an additional breaker near where the power enters the boat, as outlined in the ABYC codes. Though not often mentioned you would be well advised to install a galvanic isolator as close as possible to where the power comes into the boat. This will prevent low-voltage currents from flowing into the shore power ground wire, which will eat up your sacrificial zinc anodes.
If all of this sounds confusing, I suggest reading Nigel Calder’s “Boatowner’s Mechanical and Electrical Manual,” (International Marine) which covers shore power installations in great detail and will provide you with all the necessary information to enable you to complete the work yourself … or hire a boatyard.