Adventures in shore power.

Originally posted May 15th 2008.

When I purchased the SEA WEASEL I had it surveyed and expected a long list of things to take care of as you would find on any used 30 year old boat. One of the items that really stood out but was easy to ignore was the shore power configuration. The whole AC system was a little McGyver even for my liking. As the boat had spent its entire wetted life at Burrard Civic Marina it had had to plug into a standard house hold 110 volt outlet (Marina wiring would be another rant). So the former owner decided to rewire the shore power system from the standard marine grade receptacle in the cockpit to an open junction box with a 110v house plug in the anchour locker and rewire the boat with house hold wire. Additionally there was a Moto-Master battery Charger “installed”. The surveyor correctly identified this as a major fire hazard. I put it on the list and finally got to it one year after owning the boat. I decided to rewire the boat properly and here is how I did it. Read about how marine AC wiring is supposed to work. I read an article by Don Casey which was really helpful and used it as a guide for the project. See attached.First understand what you have in place. I basically followed around the whole system and figured out how it was laid out roughly. This involved some minor dismantling and busting out the flashlight. It would probably have helped to sketch it out but hey I am not the brightest lad so I just committed it to memory and this probably explains a few of my mishaps.I drew out how I expected the layout to work from the dock all the way back to the receptacles. I roughly measured the distances for the cables by eyeballing it. The old marine adage of “measure once; go to West Marine twice” applies. Get a list of supplies; to be honest I didn’t do a very good job on this part and made no less than 6 visits to the hardware store for little items. Here is what I used and where I got it; the prices are a guess from memory and I won’t include the items I broke or otherwise did not use:Three Prong Household Plug to 30 AMP Shore Power Adaptor – Craigslist $1050’ 30 AMP Shore Power Cable – Craigslist. $35Stainless Steal Marine 30 AMP Shore Power Cable Receptacle - On the boat already. - $07’ 10 Gauge 3 Strand Marine Grade Wire – Martin Marine - $3012’ 12 Gauge 3 Strand Marine Grade Wire. -. Martin Marine - $3620 AMP Dual Pole Breaker. – On the boat. - $0GFI Receptacle. – Canadian Tire. - $16Household Switch. – Canadian Tire. - $1.502x Household Receptacles. – Canadian Tire. -. $33x Covers. – Canadian Tire. - $2Crimping Terminals. – Steveston Marine. - $10Crimping Butt Joints. – On the Boat. - $0Shrinking Tubes. . - On the Boat. - $0Rescue Tape (could use vinyl tape).-. On the Boat. - $0Souder. - On the Boat. - $0Zap Straps. - On the Boat. - $020 AMP 2 Bank Battery Charger with Isolator. – Steveston Marine. -.$120Wire Adhesive Organizers. – Home Depot. - $6Wire Stripers/Crimpers. - On the Boat. - $0Wire Cutters. - On the Boat. - $0Utility Knife. - On the Boat. - $0Screw Drivers. - On the Boat. - $0Soldering Iron. - On the Boat. - $0Heat Gun. - On the Boat. - $0In total the budget was $269.5 but again this could cost more or less depending on how much stuff you have kicking around on your boat and the size of the project. Starting from the dock’s 110 Volt house hold panel I got an adapter to proper marine grade shore power cables. I bought this off Craigslist in addition to a 50’ 30 AMP Shore Power cable. This was all really cheap compared with retail. I had an existing stainless steel screw down sealed receptacle in the cockpit on the port side. I was able to access it from the lazerrette easily and attached the three strand wire to the appropriate terminals. I used the 10 gauge wire as recommended and made sure it was marine grade (marine grade wire is designed for flexibility, chemical resistance and corrosion protection). This stuff was expensive! I ran the wire along the inside of the lazerettes attaching it with adhesive 3M clips. I am not sure how these will hold up but it is better than drilling holes. This wire terminates in the 20 Amp Breaker Dual Pole that was on the boat. For all of the terminals where the wires needed to be screwed on I crimped the end of the wire to a terminal, soldered it and used shrink tubes to seal them. From the breaker I ran 12 gauge 3 strand marine grade wire to the various receptacles. The first receptacle was a plug near the ice box. I decided to replace it with a GFI unit, like the ones used in bathrooms, they provide shock protection in damp environments. All you need is the first one in the chain of receptacles to get protection. The wires leading out from the first plug were split off with one leading to a plug in the battery compartment and the other leading to a plug in the main cabin. The plug in the battery compartment was going to have a switch in the line so that it could be turned off. It is not recommended to run a charger while discharging the batteries. Really I am not to sure about this but I decided to give myself the option. These systems were very easy to setup and more time was spent organizing the wires. I only removed the old shore power cabling as I went along so that I could follow its path more easily. In the end was terribly inefficient with my time mostly due to poor planning but in the end I spent about 8 hours messing around with this and now have a brand new and safe system. I think this would be easy for anyone to do and reading the attached primer really helped a lot. I think this is one of those jobs you don’t want to cheap out on either. Good luck!