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Baybilly
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Discussion Starter #1
This subject may have been tackled before, but I haven’t seen it in this forum.


Early February, central Chesapeake, 62 degrees – we’re goin’ sailing!

I disconnect the shore power cord (first at the dock) then coil it up as I move around to the connection port in the cockpit. I loosen the black ring – as I’ve done hundreds of times before – yet the cord seems to be glued in place. After giving it a good tug, it separates to reveal this: (see images below)

All of the AC wiring, and the breaker panel on the boat are less than five years old, and the power was still flowing – no breakers had been tripped.

I took the cord to the local WM and showed it to a seemingly knowledgeable fellow who was certain that moisture-induced arcing was the culprit. He said it was not an uncommon phenomenon. All it takes is a little moisture to work its way between pin and socket and POW. Sometimes it could burn your boat up. He said it doesn’t necessarily damage any of the boat’s internal wiring (but strongly suggested inspecting everything thoroughly – which I did). He also said that this could happen regardless of the amount of load on the line. In fact, this could occur without ANY load at all.

I’ve since replaced the socket and the power cord, just to be safe.

Can anyone add or refute any of this? Also, does anyone have any tips for preventing it?

Thanks,

G.
 

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A product that I have used for years is Grote Ultra-Seal it is a non conductive grease that encapsulates the connection to prevent moisture from getting in between the conductive surfaces. I used this stuff in the Coast Guard all the time on receptacles out on the decks. Before a storm or heavy seas I would go to each outlet and put this stuff in the receptacle to prevent sea water from getting in and causing unwanted grounds. It saved me a lot of repair jobs and was well worth it. Hope this helps.

Jeff
 

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Baybilly
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Discussion Starter #3
Thanks, Jeff.

Would this product work for cords that were being repeatedly connected and disconnected?

Geoff
 

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I found that if you pack the receptacle side you will get a few plug and unplugs out of it before you need to squirt a little more in. It will go a long way. I use this stuff on pretty much any kind of electrical plug. I have used it on VHF antenna cables to canon plugs used on radar systems. West Marine sells one but I have found cheaper versions at auto parts stores that are just as effective cause you know when the word Marine gets put in front its good reason to double the price. What your looking for is a Dielectric grease to prevent corrosion and moisture caused arcing. Spending a lttle on this could prevent major arcing in the future and possibly your boat.

Jeff
 

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Geoff,

Also one thing that I forgot to mention was when I say receptacle side I mean the female side to put grease in. So you could grease at the shore power receptacle on the dock then the female plug on the cable.

Jeff
 

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Baybilly
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Discussion Starter #7
Bubb -

I was unaware of the warranty - thanks.

Jeff -

Appreciate the info. I'll check it out.

Geoff
 

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those 30 amp twist locks are terrible
they often make poor contact which causes arcing which caused the problem you have. Make triple sure you have a solid contact EVERY time you plug in.

I doubt marinco will give you a new cord. operator error or a bad plug on the other end can easily be blamed. Please let us know if you succeed in getting a free replacement

this happens ALL the time, ask around the docks to see everybody's plugs, you'll see plenty of burned connectors
 

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██▓▓▒▒░&
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Salt spray can form a conductive film on anything. I'd second the vote for grease. Silicon dielectric grease, aka "high temperature brake grease", will also do the job and may be easier to obtain. $8 for 1/3 ounce from the Ancor brand at chandleries, or $5 for six(?) ounces at an auto parts store, pretty much the same stuff.

The other thing to do might be to try keeping the connections out of the weather, using a leather or vinyl cover over the sockets, and an occasional fresh water rinse--or something similar to make sure salt spray isn't building up on them.
 

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Baybilly
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Discussion Starter #11
farmboy, hello,

Thank you both.

xort -- you're right about that. It's much more common than I thought. Just really freaked me out to see it on my own boat.

Another tidbit: Mr. WM said he saw this problem less often when the connection ports (at the boat) were the metal types with the screw-on caps -- as opposed to the plastic ones with the flip-up caps. Interesting. I have the latter - I think I'll invest in the former.

G.
 

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Geoff;

I just attended the electrical seminar at Fawcetts (given by the contractor who repaired the lightning damage on Glory).

He showed several examples of shore power connectors much worse than Spirit's. He stated the cause as poor (read loose) mechinical contact on the M/F connector union. He said not to rely on the little ring to maintain contact, but to add stress relief in the cord (both on the dock and boat side) and secure the cord with a short length of line to prevent the cord from coming loose during tide changes, wakes from passing boats, etc.

Good luck;

Cappydave
 

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Telstar 28
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Instead of that, I usually wrap the cord around the post once or twice...which provides strain relief quite well without requiring any additional stuff. :)
Geoff;

I just attended the electrical seminar at Fawcetts (given by the contractor who repaired the lightning damage on Glory).

He showed several examples of shore power connectors much worse than Spirit's. He stated the cause as poor (read loose) mechinical contact on the M/F connector union. He said not to rely on the little ring to maintain contact, but to add stress relief in the cord (both on the dock and boat side) and secure the cord with a short length of line to prevent the cord from coming loose during tide changes, wakes from passing boats, etc.

Good luck;

Cappydave
 

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Telstar 28
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Might be worth getting and installing on the boat and making up a couple of shore power cords for it as well. :)
 

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Whilst I know how cool it is plugging a cable into the side of the boat, I have long ago taken to having my shore power cable as just an extension with a socket wired up inside the boat. The socket on deck has been redundant ever since.

That way the connection to my systems is always dry and the only (very) mild irritation is a cable hanging down alongside the companionway.

And like SD, I wrap the shore end around the post on the dock and I also have a tie taped onto the cable that I fasten to my anchor winch with an appropriately long loop (6 inches longer than the dock line) between the boat and the dock.
 

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Baybilly
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Discussion Starter #18
Thanks for your input everyone.

That SmartPlug system seems to have addressed all of the problems in the now 70 year old (70 years!!) design standard that we use today. I'm definitely going to investigate it.

G.
 

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Coincidentally, I received a weekly email from MadMariner, showcasing a SmartPlug product which may address the problem. Could not find a price. SmartPlug Shore Power Connection | MadMariner.com
My dock neighbor is the inventor of that product. Saw it at the the trade show a few weeks back (didn't know it was my neighbors that invented it until then). Solid product and well thought out. The only drawback I see is the price and the fact it is basically worthless if the marinas shore power doesn't have their style receptacle. They do have an adapter plug for marina shore power to their system but in my opinion - kinda defeats the purpose. I regularly get reverse polarity when the shore power cable gets jiggled a bit as at my marina they do not have the type that allows the screw / secure thing...However nice product and the design is solid - just with the economy as it is - I think it maybe one of those inventions or "new" ideas that never make it mainstream.
 

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██▓▓▒▒░&
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I think they'd need some seed money to give away a couploe of dozen thousand of them to major marina chains, in order to prime the pump and give boat owners a reason to buy them. And then, other marinas a reason to use them.

Or convince insurers that they are so much safer, marinas using them deserve an insurance break big enough to cover the cost of buying them.

Sure looks like a better mousetrap--but the old mousetraps are long bought and paid for.
 
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