SHORE POWER... et al.

[roadnsky]

Not the same as Neil's topic on gas vapor safety but good fodder for another thread discussion... SHORE POWER connections.

• Power cables draped or running thru the water
• Turning off the breaker BEFORE disconnecting shore power
• Rusted, pitted, cracked connectors
• Improper wiring onboard many vessels (gauge, wire type, circuit breakers)

These are just a few of many that contribute to a recipe for a dangerous boat fire.
As I said, fodder for another thread discussion.
(maybe I'll start it)

Ok, I started it, so I'll get the discussion rolling with this new thread.

As I wrote in Neil's thread, Shore power and the various related connections are another topic for needed attention and safety on our vessels.

Walking the docks at my marina (or any marina actually, I'm amazed how many times I see cables - from shore power to household electric cords - dangling in and thru the water from the shore power outlet to the boat.
Sometimes the entire length of the boat... in the water.

Another is how many times I see someone disconnecting the shore power connection without first turning off the breaker.
Sometimes, to my horror, I watch some actually then toss that HOT cable end onto the dock.

Finally, I was invited onto an old Columbia the other day by a guy who had recently bought her. While being shown around, I noticed his AC Circuit Breaker was hanging with the back of it wired "hot" with wire nuts.
He explained that the breaker kept tripping, so he wired "past" it.
Note here that he LIVES on this boat full time.
Yes, I warned him of the danger and admonished that he make repairing it the first priority.

I have others but I'll save them and use these few as a downpayment for a forum discussion.

I think a great goal would be to come up with a punch list of items/issues/solutions for onboard safety that some may not know.

[ndutton]

Does this look familiar?




It is caused by a high resistance connection. It may be due to looseness (twist lock not twisted, plug displaced by kicking or cord stress) or corrosion or maybe a combination. Also, the greater the amperage going through the connection, the greater the damage over time. It's a slippery slope. Once the connection is damaged even slightly the resistance is increased which causes more heat which causes more damage which causes more resistance which causes more heat and the cycle repeats to the point of destruction. In my work I have seen such damaged components glowing red under load. At least it was contained in a fire rated box installed in a fire rated wall. Apply the same condition on a fiberglass boat and you're asking for a barco flambe'.

Amperage is a contributing factor but it need not be greater than the breaker value for such damage to result therefore the breaker does not trip to protect in this scenario. Even a GFCI or ELCI will not trip as the fault they protect against is not present. In other words, you have no automatic protection installed for this problem.

You'll never see the damage on the keyed ground terminal either because it does not carry any load, only the hot or neutral terminal. Looking carefully at the picture you'll see the ground terminal is the uppermost and still pristine.

[Ando]

I am usually very careful about the shore power and it’s tidiness, but I was caught slipping one day by no other than ndutton who was stopping by to help with some diagnostic testing. The shore power was uncharacteristically just all of a sudden sitting there partly within the water. I couldn’t believe it. I believe his exact words were, “this is bad form.” Gotta love this man. Thanks.

[ndutton]

Some day we will talk about how to properly make up cleats, the direction the wood grain should go on cabinetry, fasteners on deck hardware and screws on electrical cover plates.

[ronstory]

I've adopted the wisdom of the Smartplug, and will never go back to the marinco style twist-n-lock.

If you are not familiar with them, please read Rod Collins's thoughts on the evolution of our shore plugs.

https://marinehowto.com/shore-power-cords-smartplug-vs-1938/

... and to keep those pesky shore power cables from dangling into the water, IMO these (below) have been worth the money. Especially after I cut down our 50' dock cable with the smartplug to meet the 'long end' of our boat when it's docked bow first. It now fits perfectly with a bit of margin and clips to keep it organized.

https://www.amazon.com/Marinco-Electrical-Shore-30-Amp-10-Gauge/dp/B000NI38YY

[Dave Neptune]

Paying attention

I have operated a sailboat in a marina since 1968 and until July of 2017 I have never had "shore power" nor had to deal with it. My new to me Bene does have shore power and I don't use it all the time. I have always relied on checking the boat regularly and checked battery levels. If I needed to charge or do work on the boat I plugged in with an extension chord to the battery charger kept in the dock box. I doubt I plugged in more than a couple times a year if I needed power or the rare charge.
My '74 E-27 was an OB model so I did not care if the battery was a bit low as the engine would have it charged by the time I got "there or back". The OB was a magneto ign so I could pull start or use the starter. No fridge and 2 grp 27's worked for many years. When we decided to get a bigger boat I looked for a boat without the "shore power" for simplicity and as I lived close to the marina if the batteries got weak I'd fire it up to charge. The "start" battery always worked unless I screwed up. This boat was Volador an E-35MKII I had for 34 years and an A-4!
Now I have the Bene, a diesel, refrigeration, shore power and solar. On this boat I still only plug in if I want some "110" in the boat for the vacuum or tools for projects. The S/P is often turned off an the boats panel so the plugs are not hot and the charger is "off line" a great deal of the time. I do rely on the solar for about 70% of the time. If I leave the boat since I moved I will turn on the "110" for the charger if there is a lot of rain which diminishes the solar charge some and I still have not found the batteries charge low enough to be concerned. In fact I seldom plug in after a cruise to save time and often plug in when I arrive to pack and clean, most often not.
The one thing I do is be sure things are not under a load when un-plugging. And I do use a bit of di-electric grease on the "plugs". Not sure if this is a good practice however everything works real nice. Niel?
I have always been one to work my batteries and check them often.

I must admit I do use a "boat warmer" through the winter especially if I am staying aboard which I do a few times a month now that I am a hundred miles from the marina in retirement.

I now do get a kick out of reactions to my prized MMI coffee mug. It is often noticed and I get the usual raised eyebrow or comments. They really go bonkers when I tell them I am going to mount 2 A-4's in the Bene for the twin engine reliability.

Looking forward to learning something here!!!

Dave Neptune

[ronstory]

Being in a cooler climate, our boat has the shore power plugged in all the time and runs the our compressor based dehumidifier. It has made a *huge* difference in keeping the boat smelling "fresh" during the winter months. Of all the things I've added, this make the top 10 list for bang-for-buck items on the boat.

As for the mighty smartplug install, we had a traditional marinco shore power plug and was in good shape. The smartplug retrofits the shore cord connection to the boat and also the receptacle on boat. The install is straightforward can would have only taken 30-40 mins, but I discovered the the hole for a receptacle was a bit oversized and needed reduce the hole by 1/4 inch for it to seal well. That took 2-3 hours to prep and finish.

There was an 'uh oh' moment was when I removed the old receptacle from the boat. While it looked in great shape from visible connections on the outside, looking at the back side the hot lead was developing a burn mark on the back. Absolutely no indication from the outside, so I was lucky... and now have a extra checklist item for spring commissioning.

While I was there, I also installed a Yandina galvanic isolator in the ground line to give ~1.2V offset protection. Not expensive and really easy to install with the receptacle out. With the galvanic isolator installed our zincs are now lasting twice as long. We we are on a record run, I'm at 15 months and may make it to 18.

[roadnsky]

Once the connection is damaged even slightly the resistance is increased which causes more heat which causes more damage which causes more resistance which causes more heat and the cycle repeats to the point of destruction.

Thanks Neil.
That is one of my main reasons for raising the "Shore Power" discussion.
It's a very serious and well hidden danger on many vessels.
And...possibly and very likely your slip neighbor as well.

Another contributor to Neil’s “resistance formula”
is damage (pitting) caused to the pins of the plug by the common practice of disconnecting the plug at the boat while the power is still on.
(Breaker at the dock panel)
This can cause a small arc that burns the pins in both the plug and receptacle.
Adding still more resistance into the equation.

There is a good article about this and other shore power issues here.

Edit: Like Ron, I'm a SmartPlug disciple as well.

[ndutton]

An investment in the future of this thread

I encourage everyone to take the time and read the first link ronstory provided in the fifth post. The technical aspects of the Smart Plug article are both thorough and spot on. After reading it ask yourselves, are the merits of the newer technology reason enough to install one on your boat even though it is neither ABYC nor USCG approved?

[ronstory]

Neil brings up a great point about Smartplug certs. After a bit of googling... the most interesting data I've found on why they are not ABYC approved is:

https://www.trawlerforum.com/forums/s4/50-amp-smartplug-37890-2.html

Check out post #21. It's seems it's an IP issue.

[roadnsky]

Hopefully not to get too far off the main topic - Here are reviews by...
• PRACTICAL SAILOR
• CRUISING WORLD
• BOAT US

They each mention the UL rating issue.

The SmartPlug meets rigorous Underwriters Laboratory Marine requirements (as tested by IMANNA Labs) and the American Boat and Yacht Councils E-11 safety standard, according to the company.
It also is Coast Guard compliant.

The Practical Sailor review (update March 2020) says it's Coast Guard compliant? Is this new?

[ndutton]

I expect at some point it will be embraced by the standards agencies so the related comments here may be time sensitive. Regardless, the question is does agency approval matter to us as boat owners if the product is high quality and solves a dangerous issue?

It didn't matter on my boat. I bought a Smart Plug, examined it carefully (unlike Rod Collins I didn't cut it apart) and decided it was truly a better mousetrap whether the Coasties realized it yet or not.

[roadnsky]

...the question is does agency approval matter to us as boat owners if the product is high quality and solves a dangerous issue?

Yep, excellent point. On my vessel, I'm with you.
I most definately want something that is the safer product and in this case will give a much greater chance of NOT burning my boat to the waterline.
and... very likely, with me IN IT.

Nice install BTW.
I guess my inlet is older. (2013) It doesn't have the embossed cover.

[joe_db]

When I was in the boat fixing business some of our biggest challenges and the source of a few painful shocks was the various misconfigured shore power systems we encountered.
A couple safety notes:
1. Boats with inverters can kill you with the shore power disconnected.
2. Boats without inverters can kill you when "helpful" people passing buy plug the shore power cord back in.

I had both arms deep in a panel on hot July day, so I was nice and sweaty and thus quite low resistance, when someone passing by plugged the boat back in. I think the only reason I am not dead was each arm was bridging a hot and ground bus instead of one on each side. That HURT I hid the cord after that!

[Bratina]

Yep, excellent point. On my vessel, I'm with you.
I most definately want something that is the safer product and in this case will give a much greater chance of NOT burning my boat to the waterline.
and... very likely, with me IN IT.

Nice install BTW.
I guess my inlet is older. (2013) It doesn't have the embossed cover.

Lovely installs, both. Two questions:

1. What is the likelihood of this leading to a repudiated insurance claim, in the (significantly less likely) case of a fire?

2. Can I re-use my existing power cord, albeit with a new adapter at the boat end? Does that reduce / remove the benefits (or, alternatively, can the plug be used at a standard dock socket)?

Also I've heard a lot about the issue of dangling a shore power cable in the water - something I don't do. What's the risk here? Not at all suggesting there isn't one, just curious what the issue is, given the cable is insulated.