Engineer’s Angle: Shore power connection can be stressful, but new adapters helpJul 9, 2018 by JD Anson
by JD Anson
Modern shore power converters have made dock power connections a breeze. You say you have 400VAC 3phase 50Hz at the pedestal? No problem. I’ll just plug it in, push a couple of buttons and off we go to watch the sunset. Gone are the days of manually switching transformer taps, hoping to get the voltage right, and using bulky rotary converters to change frequency.
But one still must get the power to the boat. Across the world, or even across town, there exists a multitude of shore power plug standards that can cause frustration at the end of a long passage. Three-phase or single? 208, 240, 380, 400, 415 or 480VAC, etc. Five pins? Four pins? Three pins? No pins?
Unless the boss has a very loose checkbook, and the boat has a space not dedicated to 50 sets of place mats for 14, there is virtually no way the next yacht you walk on to is going to have every situation covered. With each plug costing north of $500, the cost adds up quickly. And since there are usually two shore cords on boats of any appreciable size, there is a large fortune tied up in keeping the beer cold.
Many yachts have adapters made up. One end has a female connector that mates up with the male plug permanently installed at the end of the boat’s shore cord. With a few feet of cable between, there is a male plug for a particular dock outlet. This is quite convenient, but more than doubles the cost. If the boat only sails to ports that share a couple of standards, this can be fairly cost-effective.
Some boats carry several different common plugs and swap them out on their main cables when necessary. For the odd configuration, the marina will usually have some plugs to loan. Hopefully, the boat next to you has not taken the last available plug. This is not difficult or time consuming, but care must be taken to ensure each conductor lands on the correct pin. Since engineers all have strengths and weaknesses, some may be apprehensive about rigging up to 100 amps of power in front of the boss and hoping to get it right.
There is a third option. A new company formed by a former yacht engineer who was fed up with just this scenario has created a quick-swap adapter kit. The cord end carries a U.S.-configured three-phase plug. When a different configuration presents itself, just click on a twist-to-lock adapter and the dock power in more than 20 countries is covered. There is also an adapter that can be rigged up as a bare wire pigtail, a Cam-Lok connector set or even one of those odd plugs for out-of-the-way places. It all comes in a waterproof hard case for easy storage and costs about the same as buying these connections a la carte.
Regardless of what your storage and budget allows, proper care of the boss’s investment in hyper-priced plastic plugs is crucial to your safety and the ship’s well-being. As rugged as they look, they are still electrical components. They need to be kept in a clean, dry place. I have pulled from the bilge 5-gallon buckets of rusty garbage that used to be a few thousand dollars worth of the connectors I needed right now.
If you drop the end in the water while passing the cord to the dock, it is not the end of the world – but you will be a bit late to the pub. The plug needs to be fully disassembled and rinsed with fresh water, then electrical cleaner. Dry it thoroughly with clean, dry air and put it all back together the way it was. A top tip is to scratch the conductor color into the side of the plastic next to each pin during disassembly. This makes it all go back together easily and helps in the future when you have to put that plug back on after returning from your cruise to the ends of the earth.
Worse than not being able to get the plug in, is not being able to get it out of the socket. Worn or dirty contacts in the pedestal or plug will promote a slow arc welding of the pins to their sockets. A light coat of dielectric grease on each of the plug’s pins will help prevent corrosion, and thus having to cut the cord off and leaving half a grand behind in the dock pedestal.
With a little forethought and some common sense care, connectors and plugs can last for years of worry-free use. But neglected, they can easily result in an unhappy owner and crew.
JD Anson has more than 20 years of experience as a chief engineer on megayachts. He is project manager at Fine Line Marine Electric (finelinemarineelectric.com) in Fort Lauderdale. Comments are welcome below.