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The marina which is also our home seems to have above normal electrical problems with their power boxes we connect to. Over the summer a couple of the power boxes have caught fire or over heated to the point of melting the box connections or cords on several boats. Last week one owner just happened to be on his and looked up and saw the box smoking and pulled his cord to find the connector burned and melted on the power cord. Today another boat had the issue where it burned on both ends of the power cord. The marina blames the boats saying they are overloading the cords. The breakers on the dock or boats are not blowing which is the worry. Can see several dock boxes burned. Looking for thoughts on how we decide if this is a marina issue or a boat issue as quite a few have had this issue off and on. Know my boat I'm conscious of not running the AC with hot water heater, microwaves, ladies with the hair dryers and such together. Not sure how to check to see if the dock box is adequate for what it supplies or more fault from the boats. Stayed at other marinas and never saw this many issues. Any thoughts appreciated

thanks
 

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Loose connections or dissimilar metals not properly treated. Corrosion of the connections is another possibility. Doubtful a marina wide load issue, more likely a connection unable to handle the loads.
 

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Once known as Hartley18
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The marina which is also our home seems to have above normal electrical problems with their power boxes we connect to. Over the summer a couple of the power boxes have caught fire or over heated to the point of melting the box connections or cords on several boats. Last week one owner just happened to be on his and looked up and saw the box smoking and pulled his cord to find the connector burned and melted on the power cord. Today another boat had the issue where it burned on both ends of the power cord. The marina blames the boats saying they are overloading the cords. The breakers on the dock or boats are not blowing which is the worry. Can see several dock boxes burned. Looking for thoughts on how we decide if this is a marina issue or a boat issue as quite a few have had this issue off and on. Know my boat I'm conscious of not running the AC with hot water heater, microwaves, ladies with the hair dryers and such together. Not sure how to check to see if the dock box is adequate for what it supplies or more fault from the boats. Stayed at other marinas and never saw this many issues. Any thoughts appreciated

thanks
What brand/model power boxes are the marina using? Or are they custom jobs? How old are they (ie. when was the marina built)? Do you have a photo of a burnt one??

  1. It's quite possible it's a loose connection/corrosion issue... but I'd expect that if only one failed - not a few of them, unless
  2. If they're custom-made, they could contain either poor quality electrical gear or gear that is not marine-rated and thus shouldn't be there in the first place.
  3. It could also be a design issue: The people who did the power distribution system design didn't make adequate allowance for earth fault or phase imbalance, meaning high currents in dockside cables and connections that aren't designed for it.
It's highly unlikely to be a 'boat' issue.. it sounds like more of a 'many boats connected at once' (marina) issue to me.
 

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Mermaid Hunter
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The marina which is also our home seems to have above normal electrical problems with their power boxes we connect to. Over the summer a couple of the power boxes have caught fire or over heated to the point of melting the box connections or cords on several boats. Last week one owner just happened to be on his and looked up and saw the box smoking and pulled his cord to find the connector burned and melted on the power cord. Today another boat had the issue where it burned on both ends of the power cord. The marina blames the boats saying they are overloading the cords. The breakers on the dock or boats are not blowing which is the worry. Can see several dock boxes burned. Looking for thoughts on how we decide if this is a marina issue or a boat issue as quite a few have had this issue off and on. Know my boat I'm conscious of not running the AC with hot water heater, microwaves, ladies with the hair dryers and such together. Not sure how to check to see if the dock box is adequate for what it supplies or more fault from the boats. Stayed at other marinas and never saw this many issues. Any thoughts appreciated
A little of this and a little of that most likely.

The 30A twist lock connectors leave a great deal to be desired, especially as oxidation builds up. Oxidation increases resistance which increases heat which leads to scorching of the connectors. This is a very frequent problem with boats that run their A/C a lot.

Add to that the possibility of loose connections inside the power pole and the heat can get rather high, all without blowing any breakers.

As noted above the power distribution systems in many marinas aren't all they could be. Most are wired by electricians who don't frequently deal with the corrosive environment, large temperature swings, and high vibration environment of a marina. Look for signs of overheating inside the power pole. Terminations should be in accordance with NFPA guidelines for marinas.

Boaters don't help. "Hot-plugging" cord sets is tough on them. Breakers on the power pole should be off while plugging in and turned on only after everything is connected. Those spiffy cord covers trap heat in the cord which isn't good.

Marinco advises: "Look for signs of corrosion or overheating. Examine ends of cord set, face of inlet on boat, and receptacle on dock. Look for corrosion, discoloration or melting. If evidence of corrosion or overheating is present, DO NOT USE AFFECTED ITEM. Replace item or seek qualified help."

I suggest reaching out to the marina management in a collaborative fashion and try to get everything - infrastructure, procedures, inspections, and usage - improved.
 

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The marina which is also our home seems to have above normal electrical problems with their power boxes we connect to. Over the summer a couple of the power boxes have caught fire or over heated to the point of melting the box connections or cords on several boats...

...The marina blames the boats...
We had similar problems at our marina after hurricane Sandy submerged the whole marina for several days.

Same thing, the marina blamed the boats, didn't want to spend the money.

Let me ask you this, have you ever seen a fiberglass boat burn? Now imagine trying to get out of your boat, your home, at 4AM while its on fire and burning with the ferocity of a fiberglass fire.

That's the image that kept going through my mind. That's why we moved. It's hard changing marinas. You get attached, you have friends. Now re-read the previous paragraph and decide if it's worth staying. Online threads speculating long distance on what might be the problem are a waste of time.

If you're living in a fire trap common sense says get the hell out.

And if the owners had any shred of moral responsibility there would have been an electrician looking at the problem after the first electrical fire. Their actions tell you everything you need to know.
 
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I'll second what Jim just stated.....get out before disaster strikes. We had a huge marina fire nearby at Colonial Beach, something like 70 boats were lost. Once these fires start, there's not much to stop them, they burn fast and spread fast because of the fuel and fiberglass.

If you're in Alabama, has the marina piers ever been underwater because of a hurricane or other? Salt water will wreak havoc on the electric pedestals.
 

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The marina which is also our home seems to have above normal electrical problems with their power boxes we connect to. Over the summer a couple of the power boxes have caught fire or over heated to the point of melting the box connections or cords on several boats. Last week one owner just happened to be on his and looked up and saw the box smoking and pulled his cord to find the connector burned and melted on the power cord. Today another boat had the issue where it burned on both ends of the power cord. The marina blames the boats saying they are overloading the cords. The breakers on the dock or boats are not blowing which is the worry. Can see several dock boxes burned. Looking for thoughts on how we decide if this is a marina issue or a boat issue as quite a few have had this issue off and on. Know my boat I'm conscious of not running the AC with hot water heater, microwaves, ladies with the hair dryers and such together. Not sure how to check to see if the dock box is adequate for what it supplies or more fault from the boats. Stayed at other marinas and never saw this many issues. Any thoughts appreciated

thanks
Sadly this has more to do with the piss poor wiring standard we use in the US for shore power. Owners DO often overload these plugs/sockets and the reality is that once they are beyond new pushing most 30A services to more than 20A - 24A can result in tremendous amounts of heat and potential fires. Corrosion and poor plug socket design both lead to high resistance. There could also be corrosion in the pedestal connections. The voltage issue needs to be addressed but it could be caused by corrosion, undersized wire feeds or simply worn out sockets etc.

Circuit breakers trip on 'overload" but you CAN start a fire at well below "overload" due to high resistance.

Smart Plug vs. 1938 (LINK)
 

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As above, if the circuit breakers are not tripping and you are getting fires and charred connectors, it is not a amperage problem, but a resistance problem. I can't imagine a marina not addressing the problem immediately as the danger is very high. I like the idea posed above about a cooperative system analysis to ensure all elements are to standard, power mains, panels, switches, connectors, cables, users procedures, etc.
I recently moved to a new slip and found that the connector on the panel was charred. I walked over to the marina office and told them about it. That afternoon an electrician was there, diagnosed the problem and told me it would be fixed the next day. He then Put a big red and yellow danger sign on the panel and disconnected the other power cord. Now this is a city marina and they normally don't jump right on reported problems, unless they are a fire or safety hazard.
Also, if you are on 30 amp service and are running an air conditioner and a water heater, then when the refrigerator kicks on you will probably be over amped and should be tripping circuit breakers. Add up your loads especially cyclic startup loads that are not switch controlled, with more than one in startup you could easily be overloading. If that is the case, find out why the breakers are not tripping.
John
 

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I was lucky to be on the boat when the shore power connector at the boat end melted down. It was a very rainy day, which I do not think is a coincidence! It would not come as a surprise that the same thing can happen at the dock end.

As others have said, the problem is older connectors with a buildup of oxidation. Add damp conditions to the mix, and bob's your uncle.
 

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Discussion Starter · #11 ·
the boxes are made by Midwest with 2 30 amp on the box with breaker on each. Made for marina. Yes these docks have gone under with storms in the past. They don't seem too concerned and blame the boats. Don't want to spend the money and will hurt them long term. Not a lot of options close by. Have to see if we can have a group meeting with the owners. Thanks for the input
 

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the boxes are made by Midwest with 2 30 amp on the box with breaker on each. Made for marina. Yes these docks have gone under with storms in the past. They don't seem too concerned and blame the boats. Don't want to spend the money and will hurt them long term. Not a lot of options close by. Have to see if we can have a group meeting with the owners. Thanks for the input
Well.. there's your starting point for the discussions. If it's a typical marina, I'll bet they haven't even bothered to inspect one that's been under.

The system is still possibly poorly designed (the cabling to the boxes, I mean), but I haven't seen a marina box anywhere that's designed for full immersion (IP67).
 

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I did not read the other replies, what you have is a voltage issue.
Read your voltage when your applying a high draw load.
I have been to a few that will drop to 90 volts, including the last one that burnt up my cord ends, and also burned up my interior wiring. The best thing you can do is oversize your wire inside that boat, and get a heaver then required cord to go to the plug, this will keep the burn-ups at the plug, and not on the boat.
 

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Volts go down, amps go up resistance stays the same heat results cords melt/burn and breaker never trips.
P=V^2/R (* power factor for AC). So the scenario you give results in lower power, not more. How would this melt the cord?
 

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I did not read the other replies, what you have is a voltage issue.
Read your voltage when your applying a high draw load.
I have been to a few that will drop to 90 volts, including the last one that burnt up my cord ends, and also burned up my interior wiring. The best thing you can do is oversize your wire inside that boat, and get a heaver then required cord to go to the plug, this will keep the burn-ups at the plug, and not on the boat.
The voltage is not the issue here, it is high resistance that caused your issues. Corrosion & crappy plug ends (the "Twist Lock" standard we use for shore power cords SUCKS) are the most likely culprits.. Unless of course Mickey Mouse wired your boat.

There is no way a 30A load on a boat with 30A service results in melted 10GA wires at 90V. 10GA 105C wire (what is & should be used for a 30A service, as a minimum) can easily handle 50-60A and not melt.

There is a way though to melt the wires at the point of high resistance and this can be done at just 15A on a 30A service, but the voltage from the source was not the cause it was the high resistance point causing heat that was the cause....

Beyond that a 30A service with Twist Lock cord ends should not be run at 30A, even with perfect voltage, unless you want a boat fire. If your boat can pull more than 24A from a 30A service you really need a second 30A service....

That said a marina delivering 90V to a pedestal needs work....
 

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A couple have caught fire or overheated? Not exactly sure what that means, one of each or more than one of each. I ask because having a rare occurrence isn't all that abnormal. Boat manage to overload or hot plug (which can spark and scar the connector) all the time.

With your marina reportedly being underwater, it certainly raises the question of whether it was properly inspected and remediated.

I'm not one to go overboard, but if I were convinced that this was systemic and the marina had not properly addressed it, I would consider dropping a dime (perhaps anonymously, perhaps not) to the local fire department or building department. They will take the thought of burning fiberglass very seriously.
 
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30A twist lock connectors are not the best thing if you need more than 20A continuously. And way too many boat owners run them at 30A or even more. A lot of people think that a 30A circuit breaker is some magical device that trips exactly at 30A. It doesn't work like that because if it did no one could run a refrigerator or air conditioner. Breakers have a time curve where they allow much higher current for a certain time and there is a tolerance on the range of tripping current. Many 30A breakers will allow 35A for an hour or more. So people overload the circuit often unknowingly and believe they are ok because the breaker doesn't trip.

The twist lock socket is usually the culprit. The pressure of the spring contacts weakens over time, corrosion and with heating until the contact resistance is too high. Even 0.1 ohm of resistance in the twist lock will burn up the connector in less time than most breakers will trip. You should check the temperature of the twist lock every day after you know lots of appliances have been running. If it's warm then you need to do something about it. Look at the prongs of the plug end where they disappear into the rubber housing. Is there a little brown or black area in the rubber around the prong? If so you have a problem. The problem can be in either the plug or the socket and it can be where the wires are clamped into the back of either the plug or socket.

If you are a long stay resident at the marina ask if they can permanently wire the shore cord into the pedestal. Some marinas will but some codes won't allow it. If you have heating at the pedestal, pester the marina to measure your current draw and if less than 30 make them replace the socket. If the boat inlet is heating have an electrician fix it ASAP. 30A plugs and sockets should not get hot.

For air conditioners and refrigerators low line voltage can increase the current draw. These are not resistive loads that follow Ohm's law. If your AC voltage is 10% lower than specified pester the marina to fix it. 90V on a 120V circuit will damage compressor motors.
 

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The voltage is not the issue here, it is high resistance that caused your issues.
Yes, but I am not here to offer an education to everyone on ohms law.
When our cord melted, it did so at each connection. The shore box, the boat inlet, but also the wires inside the boat started to melt.
It took our our air conditioner too. That was not a bad thing thou, we went from an old unit that drew 26 amps to a modern 10 amp unit.

When I rewired, I went two gauge higher, I believe the boat had been wired in 14 gauge from the factory, I went with 10. The boat was never intended to have AC.
 
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