Shore Power Options

Questions & Answers
1

Surendira Siva's profile photo

Surendira Siva

Dec 3, 2024, 6:21:34 AM

to INA Nonsuch Discussion Group

My 1982 Nonsuch 26 ‘Inner Peace’ doesn’t have a shore power inlet, and it seems like this version of the boat was designed without it. I’m planning some winter projects on my boat.

How many of you in the group have installed a shore power inlet?

Since I’ll only be on the boat for a few hours, I’m considering not putting in the effort to install a shore power inlet and AC panel. Instead, I’m thinking of using a pigtail adapter from Marinco to run a heater and charge the batteries with a battery charger. Whenever I leave the boat, I’ll disconnect the pigtail adapter and return the shore power cord to the dock.

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2

Your plan seems fine to me. It’s no different than what contractors do at building sites all the time. And GFCI protection is really important near the water. Especially salt water.

You might want to ask your marina if the dock power is already GFCI protected. I think I read that it is the current code, but was recently added. Also, states and cities can and do adapt the national code to their own jurisdictions. So some jurisdictions may require marinas to be retrofitted with GFCI breakers and others may not. (If the marina does have GCCI breakers, you might ask if they can test yours.) If you have a functioning GFCI breaker, then you won’t need the one on the pigtail which will save you money and it will be less clunky.

This pigtail is outdoor rated, but you are right not to trust it while you are away. For example, don’t count on it to keep a heater running in your boat over the winter. It only takes a few milliamps of current to pop the GFCI breaker and then you’ve got no heat. A little salt mist washed down into the contacts could be enough to pass such a small current. I have a similar inline GFCI pigtail that I use with my tile saw and it pops from time to time just due to fresh water intrusion (probably contaminated with minerals from the sawing.)

Finally, there’s a practical question. What gauge wire is used in the pigtail cabling? A 30 amp breaker will trip with a 24 amp (80%) sustained load. And the GFCI breaker is not a load current sensing breaker, it’s just for leakage to ground (possibly through you.) So if the wire in the cabling is 10 gauge, then you can safely run three 8A or two 12A devices at once without tripping the breaker on the dock. (Total of 24 amps.) If the wire is only 12 gauge, then you need to limit your total draw to 20 amps because that’s the maximum that you should pass through 12 gauge wire.
I looked on the Marinco website and they failed to provide much useful technical information about their product. But the gauge might be printed on the cable sheathing. Or it might say on the packaging. Or you could contact them. Without knowing the wire gauge, I’d say you should limit your total draw to 20 amps.

–Brian M. Godfrey

3

The problem with the simple extension cord is that, besides not being waterproof, may not meet the requirements of the marina.

Sorry, guys, but you’ve not seen the results (close up) of fires in a marina like I have. Fortunately, a resident across from our marina was up at 3 AM, saw flames and the volunteer fire chief owned a local boatyard. 2 boats burned to the waterline along with several boats on either side being heavily damaged. I was fortunate that my boat was not downwind. Having strict rules about extension cords in my YC makes me sleep better at night.

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

4

I have a 30-amp, 50-foot cord that runs from the dock pedestal to my boat. It goes all the way through the companionway into the cabin. I plan to use the pigtail adapter with a GFSI built-in inside the cabin. Whenever I leave the boat, I’ll disconnect the pigtail, roll up the power cord, and hang it back at the dock.

Siva Surendira
Inner Peace NS26C #42
Liberty Landing Marina
Jersey City, NJ

5

… or their insurers. :slight_smile:

The standard Marinco cords really are just specialized extension cords. One difference from regular extension cords is the heavy insulation. It is hard to damage them and you really don’t want exposed wires near the water.
They also have 10 gauge conductors. You can get “regular” extension cords with 10 gauge conductors from Home Depot, Lowe’s, probably other places, but with lower quality insulation. They are still expensive compared to the cheapo 12 and 14 gauge cords, so it makes more sense to just get the right cord in the first place.

Marinco cords don’t use tinned conductors. That’s a bummer, but if you are going to buy a new one and don’t mess around changing plugs, it will be fine for years. SmartPlug uses tinned conductors, which is much better and safer, but they don’t seem to supply the adapter that you need.

Brian Godfrey

6

Actually, my agreement with his plan assumed he was using a Marinco cordset and putting the pigtail on the boat end, just as he has described it.

Having lived for 14 years in two different marinas, I’m with Joe on fire safety. I’ve seen a boat fire in a neighboring marina. A boat from our marina burned to the water due to using a Honda gas generator. (While out cruising and all were sober at the time.) And worst of all a combo boathouse in our marina caught fire due to a faulty extension cord. Three homes burned - one of them someone’s full time residence. Ours did not burn because we had a rooftop water system for snow removal which helped wet things down and I’d installed a fire pump for more thorough soaking of our cedar-sided floating home. And most importantly, I provided dock space on my side deck for the police and fire boats to do their monthly drills. So they knew right where to tie up. It’s always best to plan ahead.

The thing with fires on boats or in marinas is that they tend to spread quickly, making escape difficult. They are also much more difficult and dangerous to fight.

Brian Godfrey

7

Id encourage you to install a proper marine-grade power system.

We all plan to be really careful, e.g., roll things up and make sure they don’t get wet. But then life happens, and it’s dark, and we’re late, and we gotta get home, and the plan to, “… disconnect the pigtail, roll up the power cord, and hang it back at the dock,” doesn’t happen.

And salty, humid air and other things will start corroding the uncovered ends of that hanging cord before you know it – even if you are as good as you intend to be. I personally don’t want anything electrical sitting exposed out in the environment any longer than absolutely necessary, and certainly not for the 162-164 hours a week you’re proposing to let it hang back at the dock. There’s a reason the marine systems have waterproof covers at both ends.

If you are going to cut corners anyway, I suggest at least reading this article: Ensuring Safe Shorepower - Practical Sailor.

WHATEVER YOU DO, INSPECT IT REGULARLY. I nearly had a fire on one of my boats with a far safer and more standard set-up then you have in mind.

And check whether your insurance will actually cover you for an electrical accident caused by a non-marine-grade installation. And that you’re insured for damage to the marina, other boats, and other people.

If all goes well, then all will go well. If not, not – and in that case don’t be surprised if your insurance company doesn’t return your phone calls.

– Bob
Me Gusta
Nonsuch e26U #233

8

I see many great ideas and perspectives in this thread, I can’t think of anything more to say about safety and/or risk management.

In addition to safety, I think it is worth sharing how much shore power adds to our enjoyment of Soave.

Soave came with good ( but not perfect) power management apparatus. I don’t see anything wrong with using a 115 v adapter to run a shop vac for a few hours to clean up Inner Peace’s engine compartment (cleanliness was one of the top suggestions mechanics offered during the diesel workshop last month). I would not use the adapter to pursue the luxuries listed below mostly because I wouldn’t want to expose my crew to the safety caveats/risks. On a boat conservative/consistent standards allow crew and occasional visitors to be safe without knowing specifics about non standard practices.

Most luxuries are possible with battery power, but most are easier and less expensive with shore power :
Nice to always know our batteries are properly charged.
Nice to have a couple of our favorite cold beverages on the boat. The portable fridges these days are much better than the cold plate in the ice box setup that we have.
When humidity is difficult to manage, a small dehumidifier can makes a difference. Help smells and comfort.
Having a boat is sort of like having a mobile beach house. Using our club wifi on Soave I have the flexibility to Zoom calls from the boat and keep my laptop changed and ready to serve as a backup chart-plotter.
One of the brackets on my bimini needed adjustment, but the screw head was too damaged to unscrew. Stainless is tough to drill and my battery powered drill didn’t have enough juice. No problem for a regular drill.
After a late night at the club, it’s nice to have the option to stay over in Soave. In summer, fans are all we need to be comfortable. In the early spring and late fall a small electric heater in the owners cabin keeps us warm enough.
Shore power is surprisingly handy and I’m happy it’s available on Soave without many safety caveats. We all make mistakes or forget things… on Soave I try to make sure potential disasters have a couple failsafes in place that reveal any skipper or crew error before disaster.
Shore power might not provide the same incremental enjoyment for you and yours. A holistic view of how you use ( or want to use ) Inner Peace will guide you to outfitting choices for Inner Peace. These choices are personal, I my experience may not fit your preferences.

Enjoy,
Rob Cohen
s/v SOAVE
NS33 #009
Westport, CT

9

The sequence I was taught for disconnecting shore power is as follows:
With the boat plugged in and drawing power:

  1. Turn off the main breaker on the 110 (220 for those in other parts of the world) boat panel;
  2. Go ashore and turn off the breaker on the pedestal;
  3. Unplug the cable from the pedestal.
  4. Ensure the end can’t fall into the water (saves the cord from water damage)
  5. Go back aboard and unplug the cable from the boat.
  6. Coil the cord and stow in a safe location.

For plugging in:

  1. Pull out the cord and inspect the ends for signs of burning/arcing. If signs of arcing address the issue;
  2. Make sure the main 110 breaker on the boat is turned off;
  3. Plug the cord into the boat inlet socket (this ensures the end of the cord can’t fall in the water (in Siva’s case make sure the cable end is secured inside the cabin;
  4. Run the cable to the shore side pedestal;
  5. Ensure the pedestal breaker is turned off and the socket is in good condition;
  6. Plug in the cable to the pedestal then turn on the breaker;
  7. Return to the boat and turn on the main 110 breaker.

The short version is when plugging in, boat first, shore last. When unplugging, shore first, boat last.

Full disclosure, I often forget to turn off the shore side breaker before plugging in or unplugging.

Regular inspections of the cord and sockets are a good idea. Most pedestals do not have a method of providing strain relief for the cable and the sockets gradually wear leading to arcing, indicated by black marks around the female terminals. Black marks on the prongs on the male end of the cord are also an indication of a lose fit at the shore side socket. If the pedestal socket looks bad notify the marina office. Inspecting the cable and sockets is part of the process when I conduct courtesy Coast Guard Vessel safety inspections.

Have a polarity tester and use it. If my boat panel shows reverse polarity I take the tester ashore and check the pedestal.

Mark Powers

10

My biggest two concerns would be storing a cord where it’s potentially exposed to the elements for significant lengths of time, and verifying that there’s not just a GFCI breaker but a 15 Amp breaker somewhere in the path to whatever equipment’s being plugged in. There’s lots of stuff that can overheat if allowed to draw twice the current it was designed for.

In fact, even the Marinco 30 amp shorepower cord and boatside power inlet will also overheat if corrosion messes up the contacts. I had to replace both after a near-fire on a five-year-old boat some years ago.

If I was doing a new system, I’d definitely go with SmartPlug.

With any 110V electrical power cords around a boat, regardless of amps or connection method, I’d definitely urge regularly dosing the contacts with corrosion-blockers.

– Bob
Me Gusta
Nonsuch e26U #233

11

I have exchanged some emails with Marinco tech support. While the male end of the pigtail is a 30 amp rated connector, the conductors in the cabling are only 12 gauge which is inadequate to pass 30 amps continuously without overheating. In addition, the triple female connector is only rated at 15 amps - not per socket, but apparently for the whole subassembly. So they only rate this pigtail at 15 amps. And there is no 15 amp circuit breaker or fuse, only the GFCI.

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It is legal. (Consider an example: you can plug a 16 gauge extension cord - which is really only good for about 8 amps continuous load - into a 20 amp circuit and it is your responsibility not to overload the cord.) But it is not very practical. You sure don’t get much for the high cost of the cord and the pigtail. And I think putting a triple socket on it was a really bad idea on their part. A shop vac and a sander would exceed the rating of the cable, but not blow the 30 amp breaker. A heater should probably not be run with anything else. Attention will always need to be paid to the current draw by anything that gets plugged into it. I think this gives more credence to Bob’s concerns about things potentially going wrong after time passes and attention shifts to other things. If you do it, you’ll always have to pay attention to how much load you are putting through the 15 amp rated components.
There must be a lot of boats without AC circuits in them. What do those owners do when they need power? The last two marinas I was at in Oregon actually had 20 amp outlets and people just used regular extension cords when working on their boats. And you always need to make sure your equipment does not exceed the cord’s capacity.

–Brian M. Godfrey

12

I was at the boat, yesterday, and looked at my cable. It has 10 gauge conductors and so is fine for 30 amps. I’d be very surprised if they made them any other way. (But then I was surprised that they cheesed out on the pigtail, too…)

I think the bigger issue with the Marinco power cables is that they use untinned copper conductors. Later yesterday afternoon I talked to a guy whose cable overheated and he had to strip back a few feet before he could find uncorroded copper to attach his new connector onto. I think Bob Neches might have mentioned some similar issue that he had, too? This might be the biggest reason I think the Smart Plug is better.

Do you use a setup like this on your boat, Mark? Not being critical, just curious. I find it hard to believe that there is no safe way to use AC power on the many thousands of boats which were not built with permanent installations in the first place.

As for the pigtail we’ve been talking about, since it is deceivingly inadequate for the three 120V plugs it offers, I think it would be better to use one of their plain pigtails with a single 120V plug and supplement that with a GFCI adapter such as this: https://www.homedepot.com/p/Yellow-Jacket-1-Outlet-GFCI-Extension-Cord-Adapter-2762/204667709 I use one just like that (only yellow) with my tile saw and it does pop occasionally when a lot of silty water starts flying around. So I know it works. Just be sure to never leave these extension cord setups unattended.
And if using just a single plug pigtail, use a SmartPlug cable and pigtail (they do make them) instead of Marinco to get the tinned conductors. And then the expensive cable will already be on hand if an integral AC system is installed in the future.

–Brian M. Godfrey

13

Hello,

As others have said I think it’s paramount to install a proper shore power connection for both your safety and that of other.

Install a connection that is water tight and permanent the Smartplugs are great and an improvement over the Marinco, but there is nothing wrong with the North American industry standard.

At the very least you should have a fail safe galvanic isolator inline with the ground or better yet an isolation transformer.
A proper AC panel installed with an ELCI and reverse polarity disconnect And that panel should be bonded with the boats ground in compliance with ABYC/ USCG standards.

From there the options are more flexible depending on your requirements but please breaker everything to the wire gage.

Thanks again,

Colle

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14

Shore power is one piece of the power management puzzle. This morning, (THIS ) video was in my workout playlist. The specifics were not particularly relevant to Soave as a coastal cruiser, but I like the author’s thought process.

I did the analysis for isolation transformer vs galvanic isolator last season and concluded that isolation transformer would be overkill for Soave. So I installed a galvanic isolator to reduce the rate of anode depletion.