A few weeks ago I had a meltdown in the power inlet of my 37.5. I was running the reverse cycle heater and water heater (which I have done many times) and started smelling hot plastic. Luckily the white lead from the inlet to my power panel burned through, but not before melting the inlet and some plastic around it. I had replaced the inlet Jan '01 when I bought the boat and it worked well all summer with a/c, etc. On Friday night, my dock neighbor was not so lucky. He lives aboard an Irwin 38 CC. He went to dinner and left a heater running, which he has been doing all winter. (No lectures please, because I know this is not a good idea.) The line shorted out and burned out most of the salon interior. Absolutely amazing the damage that much heat can cause. Everything plastic is melted (e.g., TV, light fixtures) rest is just charred black. Here's my question: Our marina is doing a substantial renovation, including replacing another pier and the associated electricity and water. The owner is notorious for using the cheapest materials available and always "does it himself." Do any of you electical genuises think there could be surges/low power that's causing our problems? Other ideas? Is this just a freaky coincidence? I'm scared to leave the power on my boat but need the charger to keep up with the refer, etc. Those luxuries are why I bought a bigger boat to begin with. I couldn't sleep last night worrying about my boat down at the marina. Thanks for any advice.
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220 instead of 110?
Did they screw up in their renovations and switch your 110 line with 220? Boy that wouold be a problem Just my thoughts, I could be wrong RRegge S/V Allie Kat
Did they screw up in their renovations and switch your 110 line with 220? Boy that wouold be a problem Just my thoughts, I could be wrong RRegge S/V Allie Kat
Set Screws are a Weak Link
One weak-link that should be checked are the set screws on the shore power connector. If the screws become a bit loose then the resistance increases tremendously and hence a meltdown or worse. Why does the set screw become loose? The conductor is fine multistranded wire and it's possible, due to constant changes in temperature and vibration, such as from the diesel engine, for the strands to shift ever so slightly and hence, a loose connection. The shore power conductor is is a major current carrier and the set screws at the shore power connector and breaker should be checked to ensure they are still good and tight.
One weak-link that should be checked are the set screws on the shore power connector. If the screws become a bit loose then the resistance increases tremendously and hence a meltdown or worse. Why does the set screw become loose? The conductor is fine multistranded wire and it's possible, due to constant changes in temperature and vibration, such as from the diesel engine, for the strands to shift ever so slightly and hence, a loose connection. The shore power conductor is is a major current carrier and the set screws at the shore power connector and breaker should be checked to ensure they are still good and tight.
Local Electrician!
Don: You may be money ahead by having a local electrician come down to the boat and have him check out your circuit. This is probably a 10 min. job but they are going to have to charge a min. service charge (probably $50-70). When I started reading you post, my first thought was the power cord needed to be changed. After reading the rest of your post, it looks like there may be a real problem at the 'SOURCE'. We recently had some problems at our marina too. It turned out that someone on our dock had a bad cord and was causing curcuits to blow at the main box. Good luck, let us know what the outcome to your problem turns out to be.
Don: You may be money ahead by having a local electrician come down to the boat and have him check out your circuit. This is probably a 10 min. job but they are going to have to charge a min. service charge (probably $50-70). When I started reading you post, my first thought was the power cord needed to be changed. After reading the rest of your post, it looks like there may be a real problem at the 'SOURCE'. We recently had some problems at our marina too. It turned out that someone on our dock had a bad cord and was causing curcuits to blow at the main box. Good luck, let us know what the outcome to your problem turns out to be.
John, that's a very good point
I never thought of checking the set screws on a regular basis but you can bet that I will do so from now on. It makes sense that the constant vibration from the engine could work the set screws loose. They seem like a relatively "weak link" conceptually and probably could be better engineered for boats.
I never thought of checking the set screws on a regular basis but you can bet that I will do so from now on. It makes sense that the constant vibration from the engine could work the set screws loose. They seem like a relatively "weak link" conceptually and probably could be better engineered for boats.
Some electrical thoughts for Don
First of all, let's deal with your white cable. In AC wiring, that is what is known as the neutral wire. It eventually leads to a shore ground through your power cable, but it is a power carrying wire when any appliances are on. This is distinguished from the black (hot) wire, that is live whenever you are plugged in (regardless of whether any appliances are operating), and the green wire, which is there for safety, and should never carry current. Assuming that the polarity on the dock is correct, and probably even if it is not, your white wire cannot be burned as a consequence of the marina's electrical system. It burns because of high resistance, which changes it from being a conductor to a heater! An electrical heater, or an incandescent light, for that matter, is basically a wire that has sufficient resistance to heat up. But, if you are still not exceeding the limit imposed by the dock (or boat) circuit breakers, your power will not be interrupted, until the wire burns through. At that point, by the way, your reverse polarity light may come on. Why the high resistance? Most likely it is corrosion, which can diminish the wire's ability to make a good contact where it is connected. Corrosion can also deteriorate the wire to the point that strands break. The strands can also break through vibration or poor installation or just deteriorate through age. And finally, things can work loose. The bottom line is that when a bottleneck for the current occurs, it is going to generate heat. We often live with the mistaken confidence that circuit breakers and fuses protect us from all electrical faults, be they aboard or at home. These things protect us from over current as occurs in a short circuit, but not from a variety of other poor installations or lack of maintenance. AC kills and starts fires, so it is a good idea to check your system, really well, from time to time to avoid wiring problems. Two other things that may have happened to your boat are water intrusion at the power inlet (always shut off shore power while washing the boat) which may have hastened corrosion, and can cause short circuits, or you may not have sufficiently twisted the twist-lock fitting. This can result in a poor connection. By the way, if your boat has a 220 volt system aboard, these things can get a bit more complicated. As for your friend aboard the Irwin, I suspect it is a coincidence, since your problem seems not to be marina related. And, let's face it, did any other boats have problems? Why just the two of yours? More than likely, his boat had its original wiring, and somewhere it had become defective. There are lots of things that could have happened. A good electrician could probably sleuth it out, or maybe someone hired by his insurance company. With regard to your marina owner, if he knows what he is doing, there is nothing against him doing the wiring or the plumbing. He may even have been an electrician or plumber, in a previous life. I would imagine that there must be some regulatory codes in your area that govern what he is doing, and if he is not following them, then he would have a problem! But, back to the Irwin. I am wondering if there actually WAS a short, since a dead short should have caused a breaker to trip or a fuse to blow.....I am assuming your friend has properly protected any aftermarket installations he may have made, including solar panels. If it was a minor short....who knows? In any case, it is extremely unlikely that a surge would have caused this problem, particularly in a heater. And again, why not in other boats? Of course, we are assuming that it was, in fact, the heater, that caught fire. I am sure he had other appliances turned on, if only the water heater and his battery charger. And how about those devices that never truly turn off, like the TV? If the marina were using cheap wire, for instance, the problem would occur on the docks, not the boats. If the voltage were low, you would not likely experience problems with a heater. No, I am afraid it was most likely a problem aboard the boat. Incidentally, I must confess to having had the same white wire that burned through on your boat, recently do the same thing aboard my own! And, I am a Marina Manager/Dockmaster, so I had NO excuses. It was a lesson well learned. I had last changed the fitting about ten years ago, and I had not taken it apart since then. Never again. One last thought on marinas....it is very easy to test your marina's wiring for reverse polarity, or for ground faults (whether by land or by sea) in your general area, and for voltage. I would suggest that you give a good read to the AC section of Nigel Calder's "Boatowners' Mechanical and Electrical Handbook". The life you save may be your own!
First of all, let's deal with your white cable. In AC wiring, that is what is known as the neutral wire. It eventually leads to a shore ground through your power cable, but it is a power carrying wire when any appliances are on. This is distinguished from the black (hot) wire, that is live whenever you are plugged in (regardless of whether any appliances are operating), and the green wire, which is there for safety, and should never carry current. Assuming that the polarity on the dock is correct, and probably even if it is not, your white wire cannot be burned as a consequence of the marina's electrical system. It burns because of high resistance, which changes it from being a conductor to a heater! An electrical heater, or an incandescent light, for that matter, is basically a wire that has sufficient resistance to heat up. But, if you are still not exceeding the limit imposed by the dock (or boat) circuit breakers, your power will not be interrupted, until the wire burns through. At that point, by the way, your reverse polarity light may come on. Why the high resistance? Most likely it is corrosion, which can diminish the wire's ability to make a good contact where it is connected. Corrosion can also deteriorate the wire to the point that strands break. The strands can also break through vibration or poor installation or just deteriorate through age. And finally, things can work loose. The bottom line is that when a bottleneck for the current occurs, it is going to generate heat. We often live with the mistaken confidence that circuit breakers and fuses protect us from all electrical faults, be they aboard or at home. These things protect us from over current as occurs in a short circuit, but not from a variety of other poor installations or lack of maintenance. AC kills and starts fires, so it is a good idea to check your system, really well, from time to time to avoid wiring problems. Two other things that may have happened to your boat are water intrusion at the power inlet (always shut off shore power while washing the boat) which may have hastened corrosion, and can cause short circuits, or you may not have sufficiently twisted the twist-lock fitting. This can result in a poor connection. By the way, if your boat has a 220 volt system aboard, these things can get a bit more complicated. As for your friend aboard the Irwin, I suspect it is a coincidence, since your problem seems not to be marina related. And, let's face it, did any other boats have problems? Why just the two of yours? More than likely, his boat had its original wiring, and somewhere it had become defective. There are lots of things that could have happened. A good electrician could probably sleuth it out, or maybe someone hired by his insurance company. With regard to your marina owner, if he knows what he is doing, there is nothing against him doing the wiring or the plumbing. He may even have been an electrician or plumber, in a previous life. I would imagine that there must be some regulatory codes in your area that govern what he is doing, and if he is not following them, then he would have a problem! But, back to the Irwin. I am wondering if there actually WAS a short, since a dead short should have caused a breaker to trip or a fuse to blow.....I am assuming your friend has properly protected any aftermarket installations he may have made, including solar panels. If it was a minor short....who knows? In any case, it is extremely unlikely that a surge would have caused this problem, particularly in a heater. And again, why not in other boats? Of course, we are assuming that it was, in fact, the heater, that caught fire. I am sure he had other appliances turned on, if only the water heater and his battery charger. And how about those devices that never truly turn off, like the TV? If the marina were using cheap wire, for instance, the problem would occur on the docks, not the boats. If the voltage were low, you would not likely experience problems with a heater. No, I am afraid it was most likely a problem aboard the boat. Incidentally, I must confess to having had the same white wire that burned through on your boat, recently do the same thing aboard my own! And, I am a Marina Manager/Dockmaster, so I had NO excuses. It was a lesson well learned. I had last changed the fitting about ten years ago, and I had not taken it apart since then. Never again. One last thought on marinas....it is very easy to test your marina's wiring for reverse polarity, or for ground faults (whether by land or by sea) in your general area, and for voltage. I would suggest that you give a good read to the AC section of Nigel Calder's "Boatowners' Mechanical and Electrical Handbook". The life you save may be your own!
Thought for RRegge
220 volt power (in the US) require four wires, not three. There is an additional "hot" wire, usually colored red. This necessitates a different type of outlet, which fits a different type of plug on the shore power cable. The idea is to create a mix of cables and outlets where it is impossible to make the mistake you suggested. Anything is possible, of course, but that would be a HUGE mistake, and one that would have affected lots of boats.
220 volt power (in the US) require four wires, not three. There is an additional "hot" wire, usually colored red. This necessitates a different type of outlet, which fits a different type of plug on the shore power cable. The idea is to create a mix of cables and outlets where it is impossible to make the mistake you suggested. Anything is possible, of course, but that would be a HUGE mistake, and one that would have affected lots of boats.
Thanks Tim, but see below
Thanks for the thorough analysis. I'm pretty sure the problem on the Irwin started in the power intet, just as it did on my 37.5. That's what concerned me most. I say this because the worst damage is located high up on the boat. There is a big hole where the power intlet formerly resided in the cabin top. The damage down below where the heater was running is relatively limited. And, the insurance surveyor indicated that a short in the line was the problem. You point out that other boats were not damaged. True, but ours are the only ones on that pier with any real use in the winter. The other guy lives aboard and I visit regularly. Also, we have separately metered power so I would think the lines are coming directly from the power company. All in all, logic tells me this is a freaky coincidence, but my mind won't accept that logic late at night when I'm trying to sleep. I checked my insurance policy this morning just to be safe.
Thanks for the thorough analysis. I'm pretty sure the problem on the Irwin started in the power intet, just as it did on my 37.5. That's what concerned me most. I say this because the worst damage is located high up on the boat. There is a big hole where the power intlet formerly resided in the cabin top. The damage down below where the heater was running is relatively limited. And, the insurance surveyor indicated that a short in the line was the problem. You point out that other boats were not damaged. True, but ours are the only ones on that pier with any real use in the winter. The other guy lives aboard and I visit regularly. Also, we have separately metered power so I would think the lines are coming directly from the power company. All in all, logic tells me this is a freaky coincidence, but my mind won't accept that logic late at night when I'm trying to sleep. I checked my insurance policy this morning just to be safe.
Check the amperage
Many boats that have a single shore power inlet dangerously overload the 30 amp rating of the components. If you do a little math it is easy to see why. The water heater is usually 1500 watts or 12.5 amps, the AC if it is a 16K btu unit draws about 15 to 18 amps and a little more when the compressor starts, add a battery charger for a few amps and you are above the 30 amp rated capacity of the shore power cord and inlet. The easiest solution for this is to add a second 30 amp shore power inlet for just the AC unit. This will have to be properly protected with a dual pole main breaker. Check your equipment and add it up. Dont forget any other AC accessories you use as well. You may be surprised at the load. One last point is that your 30 amp rated main breaker is designed not to trip until it reaches 140% of its rated capacity. Which may be more than other components in the system can handle. An electrician or a good SAurveyor can check the system to make sure it is properly wired. Dan Sheehan AMS
Many boats that have a single shore power inlet dangerously overload the 30 amp rating of the components. If you do a little math it is easy to see why. The water heater is usually 1500 watts or 12.5 amps, the AC if it is a 16K btu unit draws about 15 to 18 amps and a little more when the compressor starts, add a battery charger for a few amps and you are above the 30 amp rated capacity of the shore power cord and inlet. The easiest solution for this is to add a second 30 amp shore power inlet for just the AC unit. This will have to be properly protected with a dual pole main breaker. Check your equipment and add it up. Dont forget any other AC accessories you use as well. You may be surprised at the load. One last point is that your 30 amp rated main breaker is designed not to trip until it reaches 140% of its rated capacity. Which may be more than other components in the system can handle. An electrician or a good SAurveyor can check the system to make sure it is properly wired. Dan Sheehan AMS
Good advice!
Don, Steve Dion has given you excellent advice. Hire a reputable electrician to check the power and give you peace of mind. I suspect, as others have mentioned, your problem was a poor connection at the inlet. With both your heater and water heater running, you are pulling a fair amount of current through this connection. Reduce the available path and the temperature can rise significantly at this point. High impedance heating often leads to incendiary electrical fires. Every year I examine many items with this type of failure mechanism. Since neither event occurred at the same time, and as others point out, it is likely coincidental that both you and your friend experienced problems. Follow Steve's advice. Mark Kissel Kittiwake 98H240
Don, Steve Dion has given you excellent advice. Hire a reputable electrician to check the power and give you peace of mind. I suspect, as others have mentioned, your problem was a poor connection at the inlet. With both your heater and water heater running, you are pulling a fair amount of current through this connection. Reduce the available path and the temperature can rise significantly at this point. High impedance heating often leads to incendiary electrical fires. Every year I examine many items with this type of failure mechanism. Since neither event occurred at the same time, and as others point out, it is likely coincidental that both you and your friend experienced problems. Follow Steve's advice. Mark Kissel Kittiwake 98H240
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