Shore Power Connections -- Again

[tarian]

Originally Posted by Dockhead

Well, thousands of boat fires occur every year. Statistics available on the USCG site. I don't think it's scare mongering at all to point out the dangers.

I used the Marinco plugs for decades. Never had a fire, thank god, but burned up a bunch of those Marinco connectors. In my opinion they are pure junk.

The European blue plugs are vastly superior, but the SmartPlug seems even that much better still.

A poor response , thousands of boat fires every year, were is your link, and a breakdown of what caused them , facts makes sense your post does not
fires can be caused by gas, petrol, oil, diesel , electrical. dropping of a cigarette
what are the % of fires caused by thermal heating as you as the OP have told us that you worry about this but what is your fear based on ,
Or is it I read it somewhere or heard it somewhere like most rumours and that silly article reads like a poor magazine article from Hello

[Hartleyg]

Dockhead, we went with the SmartPlug back in 2014, a year before we shoved off. Other than an issue with the rubber strain relief rotting from UV exposure (which was quickly and completely replaced by SmartPlug!) our connection has been trouble free. I did have to do some careful work installing the wires in the back of the boatside socket, as Tayana used #8 wire from the breaker panel to the socket and I think the retrofit socket was set up for #10 max.
I also installed a surge arrestor inline at the socket, as I felt the biggest vulnerability from lightning strikes was through the AC connection.


Long ago I left my shore power cord on the dock for a day of sailing - when I got back it was missing and a search of the marina turned it up powering someone else's boat. The oaf tried to tell me it was a "Marina cord" free for use - good thing I marked it with our boat name! I also mark my adapters not only with our name (paint pen is good for this) but bright stripes of colored tape, as I've seen these go walkabout in marinas.


Hartley
S/V Atsa

[Frankly]

Most electrical connecting devices (even in good condition) will be warm to the touch if operating near their rated capacity. Only takes a few seconds to feel the SP connection as you move about the yacht. If the connector is even near ignition temperatue, UR going to feel it. Poor electrical connections start fires all the time carrying less than rated current.


Also not unreasonable to consider the yacht end of the connection a maintenance item. The SP cables get replaced pretty regularly because the cable jacket material degrades. Every other cable change out the yacht end, and that locking ring is there for a purpose "use it".

The 80% derating rule is pretty universal over the NEC, and when sizing wire the 75 deg. rating tables is typically the correct selection. The higher temperature insulating ratings come into play in elevated temperature situations (multiple wires in a conduit and high temp enviroments).

Frankly

[Dockhead]

What are you saying, exactly? You don't think boat fires are caused by shore power connections?

You can do your own research, but this: https://www.boatus.com/seaworthy/magazine/seajul10.pdf concluded that most AC power related boat fires are caused by shore power connections.

This: https://quimbyscruisingguide.com/how-boat-fires-happen/ says the same thing.

I personally know someone who lost his boat due to a fire caused by the shore power connection.

That's quite enough for me to conclude that it's a risk worth mitigating. If you think otherwise then, well, it's your boat.

Originally Posted by tarian

A poor response , thousands of boat fires every year, were is your link, and a breakdown of what caused them , facts makes sense your post does not
fires can be caused by gas, petrol, oil, diesel , electrical. dropping of a cigarette
what are the % of fires caused by thermal heating as you as the OP have told us that you worry about this but what is your fear based on ,
Or is it I read it somewhere or heard it somewhere like most rumours and that silly article reads like a poor magazine article from Hello

[Auspicious]

Originally Posted by tarian

If the 3 pin 16 amp cable leading into your boat is in good condtion , your socket is tight and waterproof and good condition and it follows the usual protocol of RCD to Fused plugs the chance of an electrical fire are nil

My recollection from reading the underlying data, shore power connections are the single-most significant cause of fire.



I'm my personal experience it is cigarette lighter power points.

[GordMay]

According to BoatUS, AC Electrical is the cause of about 12% of all boat fires.

“... Most AC electrical fires start somewhere between the marina pedestal and the shorepower inlet on the boat.

BoatUS has long recommended using only marine-grade power cords with proper adapters and replacing them at the first sign of wear on the cord or pitting on the blades of the plug.

But the analysis of our fire claims has identified another high-risk area on boats more than 10 years old: the back of the shorepower inlet where the ship's wiring connects to the terminals.

Replacing the shorepower inlet on older boats if it is original, or at least pulling it out and inspecting the connections, could well save your boat ...”
➥ https://www.boatus.com/magazine/2015...boat-fires.asp

[wingssail]

Originally Posted by tarian

Your article is scaremongering , if I tied my boat with frayed warps I would expect them to break in high winds , if I did all the things you should not due with my electrical connections I might get a fire , and it is a might , but if I check my wires my connections and ensure that everything is safe then the potential of a fire are zero , this is as usual something being invented for the sake of it , proper maintenance and do as it says will ensure happy sailing,
Also the wiring of the boat needs to be looked at, highly unlikely that a modern boat form a reputable brand have wired it to blow up , the problem comes when owners start to fiddle with their boat and do it wrong
Articles like this are to drive traffic to there website and to the manufacture of the product, no matter what they tell you.
As soon as a website says I do not make anything from this Worry!!!!

If the 3 pin 16 amp cable leading into your boat is in good condtion , your socket is tight and waterproof and good condition and it follows the usual protocol of RCD to Fused plugs the chance of an electrical fire are nil
How many camper vans have you heard go up in flames due to electrical fires form this type of input.

You aslo proclaim that 55% of boat fires are electrical , but have not given boat numbers 5 boats burning in a year and 3 are electrical makes 60% + but 3 boat in the 100.000 in the US say is not really an issue , the use of percentage again is to direct fear and make people panic to go and buy a product they do not need the lack of true stats makes it a poor article

From all those boat fires which 55% are electrical I can bet my bottom ass that the electrical fault was poor wiring and battery management , i.e exploding batteries , cable not tight on the battery , poor connections etc, to say thermal conduction causes fire is extremely rare I wonder if any one can tell us with facts that it has happened

I suppose when you get older your fear levels and panic stress levels go up and the ability to think through the problem goes

I have also noted that the pictures used are from an extremely old 3 pin single phase who uses them now , no were in Europe does , the design has changed and is much more robust, a VERY poor article indeed

I don't think it is scare mongering to warn of the dangers of electrical fires on boats or of the inadequacy of Marinco plugs. They offer little protection against misuse.

However, the boat fires I have observed more often started inside the boat with heater plugs that got hot and ignited upholstery or cabinetry.

My own Marinco plugs and cord are 30+ years old, admittedly in poor shape, but they do not get hot either at the dock or at the plug on the boat. I plan to replace one of the Marinco shore power connections on the boat this month with a newer style one I've already purchased, but it is still Marinco.

In South Africa the shore power outlets on the dock were shocking (pun intended). Poor quality house hold plugs. I couldn't believe it. But Fortaleza Brazil took the prize; there the boat owners had to cut the supply line running along a railing and splice in their shore power cord, while standing on a wet metal float! Meanwhile the floats were banging together and sometimes pinching, even cutting, the shore power supply line. But we needed the power for our air conditioner.

I do like the idea of testing the plugs with the infrared laser temperature gun. that is slick.

[sailcrazy]

followingI've never heard of "hard-wiring" the shore power cord in, and just pulling it out of the locker when you need it....eliminating the shore power plugin and receptacle all together. An interesting idea!

[Auspicious]

Originally Posted by sailcrazy

followingI've never heard of "hard-wiring" the shore power cord in, and just pulling it out of the locker when you need it....eliminating the shore power plugin and receptacle all together. An interesting idea!

This is how the big boys do it.



If you go down this path I highly recommend color coding, either black/white/green or black/red/white/green in accordance with your boat. I use heat shrink as it isn't coming off by accident. You could use colored electrical tape. On the boat side I use colors and labels (H1/H2/N/G).

[Pelagic]

Originally Posted by Auspicious

This is how the big boys do it.



If you go down this path I highly recommend color coding, either black/white/green or black/red/white/green in accordance with your boat. I use heat shrink as it isn't coming off by accident. You could use colored electrical tape. On the boat side I use colors and labels (H1/H2/N/G).

Exactly! [emoji106]

[Mystic38]

Sorry..but there is no 80% rule at all.

If there was an 80% rule then a 50A cable and connector would be rated at 40A.

perhaps "Rule of thumb" is the phrase you are looking for... an approximate guess based upon some random set of subjective bias.. which as you see is a ridiculous concept..

with a well fitting, clean set of connectors there is zero need for any rule of thumb regarding utilization ratio.. a 50A cable/connector set can be run at 50A continuous.. and if it could not..it would not be a 50A cable/connector set

Conversely, to support the OP first post... with a badly fitting corroded set of connectors even a 10% rule of thumb would be dangerous.

The bottom line here should not be a discussion of whether a cable should be derated based upon a knee jerk subjective number with no validation based upon actual data, or whether the shore power should be wired direct to the boat or not, but that ALL shore power connectors and cables should be inspected and serviced regularly.

Originally Posted by ArmyDaveNY

The 80% rule is a real thing, and when it comes to shore power, many electricians recommend only 70% especially when using the old Marinco connection. I was on the phone with Marinco a while ago and they said the same thing about the 80% rule.

I have been told that the ratings are for peak draw, and not continuous power. I guess in some ways that is similar to the ratings on generators. Even engines will have issues when run at 100% constantly.

[Pete7]

Originally Posted by Pelagic

IF I was doing frequent day sails from a dock, I would simply disconnect cable lugs from engine room box and leave cable ashore.

Is this safe for general adoption by the masses?

It suggests picking up the shore power cable and taking it aboard, then making the connection with the boats supply.

I try to ensure I connect the cable to the yacht first, then take the cable ashore. If I fall in or slip well I am holding a cable without any supply. If you connect the cable to the shore power first, or the cable is hard wired and then step on board, that cable could be live.

Sure it might be switched at the shore and being safety conscious you checked before touching it, every single time. But you or a crew member only has to be unlucky once taking the cable aboard or making the connection.

Dockhead mentioned the blue European plugs and sockets, there is also a yellow 110V plug, which has a different lug position from the 240v so they can't be mixed. Ours last 5 to 6 years before they corrode. Thankfully they are cheap enough not to worry, just snip them off and start again. For a 16amp supply @ 240v which most shore power seem to be rated at they work well.

The way some folk mess about with shore power cables on the jetty is just scary at times. Another one glad to be 90% reliant on solar. The anodes last longer not connecting to shore power too.

Yacht end of shore power cable.

[Dockhead]

Originally Posted by Mystic38

Sorry..but there is no 80% rule at all.

If there was an 80% rule then a 50A cable and connector would be rated at 40A.

perhaps "Rule of thumb" is the phrase you are looking for... an approximate guess based upon some random set of subjective bias.. which as you see is a ridiculous concept..

Sorry, but this is not true. I wasn't aware of it myself, but the 80% Rule most definitely exists:


Article 210.19(A)(1)
"General. Branch-circuit conductors shall have an ampacity not less
than the maximum load to be served. Where a branch circuit supplies
continuous loads or any combination of continuous and noncontinuous
loads, the minimum branch-circuit conductor size, before the
application of any adjustment or correction factors, shall have an
allowable ampacity not less than the noncontinuous load plus 125
percent of the continuous load."


2014 National Electrical Code.

What this means is that the nominal capacity of a circuit is not indeed the real capacity for CONTINUOUS loads. It means that according to the design parameters of the National Electric Code, the conductors of a circuit rated at x amps are suitable for continuous loads of only 80% of that.



All news to me, but it is real!


See: https://www.electricallicenserenewal...sectionID=26.0

[GordMay]

Originally Posted by Mystic38

Sorry..but there is no 80% rule at all ...

WRONG!

There are, at least 4 applicable rules, in the National Electrical Code.

NEC Sections 210-22(c), 220-3(a), 220-10(b), and 384-16(c) all relate to the sizing rules for overcurrent protective devices (OCPDs).
The first three all specify the same requirement:
OCPD size = 100% of noncontinuous load + 125% of continuous load.
Sec. 384-16(c) has the same requirement, except that it's stated in terms of the loading of the OCPD. This rule states that an OCPD can be loaded to only 80% of its rating for continuous loads. Remember that 80% is the inverse of 125% (0.80 = 1 [divided by] 1.25) and, as such, the rules are indeed identical in their end requirement.


I see Dockhead beat me to it - with a fifth rule.

[rslifkin]

As a general rule of thumb, weight and cost are the only downsides to over-sizing electrical components. You get less voltage drop, less heat and as a result, things have to be much more degraded before they cause a real issue (which makes it easier to notice before things go bad). When running closer to the limits of the components, it only takes things being a little bit off to cause a meltdown.