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Old 02-16-2015, 08:28 AM   #41
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Questions, regarding both salt and fresh water dockage and electric current in water:


If there is a very good condition (like new) live-wire 30 or 50 A electric cord hooked-up to dock and boat with 3' of it dangling in water what is the amount of electric current emitted into water?


Also, considering same item as above except instead of 3' dangling in water there is only 1' or maybe as much as 10' dangling in water... does that make difference of amount electric current emitted into water?


And, if electric cord is not new, but rather it is quite old would that alter the amount of current emitted into water considering same circumstances as mentioned above?


What if the connected power cord's exterior insulation was cracked and dangling in water but interior wires were still independently insulated? How much current then released into salt or fresh water?
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Old 02-16-2015, 10:13 AM   #42
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I'm going to talk to them today. There are some "socio-cultural" reasons where I very much want to stay at this marina. I now have a proper pigtail adaptor. I figured I could make one but realized the one I had was probably home made. This was probably "ok" for occasional use while transient but it isn't acceptable for use in poor weather in the winter months. I have other Marinco adapters for the 50-30 and the 15-30 amp connections.

I'll talk to the marina today or tomorrow about the receptacle and upgrade of service. I'm going to check the other harbour authority docks to see if they have 30 amp service and go from there.


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Old 02-16-2015, 10:36 AM   #43
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The reason I asked about a heater is because it cascades to a duty cycle kind of issue. I know these cords say 30 amps, but I've found many here in the nw who have routinely melted cordsets at under 30 amps. The problems and fire history is very well documented, as well as the cause. The contacts lose good mating coverage and what's left overheats. I ultimately concluded that 30 amps is just not reasonable as a continuous duty rating in anything other than perfect as new condition and you rarely can control all the connections as at least one is owned by the marina.

Heaters of course wind up running a pretty high duty cycle. They cycle on and off, but the cord may not sufficiently cool between cycles. I did not have a problem until I wound up with a 48 foot boat. Same cord, but more space to heat. One typical heater won't do it, so then it was two and when they both cycle on at the same time, then I could be over 20 amps, let the battery charger or frig happen to cycle on and I'm suddenly trying to maximize that 30 amps that is only safe if everything is perfect, which we know it's not. I tried for a few years to change out cords and sockets and keep everything perfect, but empirical evidence of routinely feeling cord ends as I passed by would unexpectedly find a warm connection in timelines of a couple months and the process would start over. Bottom line, it's not practical.

So I went another way, invested thousands and have a very large battery bank, and a co-generating inverter and a shore power current that can be set at a limit, the inverter makes up for the peaks above that limit, usually about 15 amps. The cord never gets asked to run more than 15 so does not overheat, and so long as the average current is below 15 amps I can handle the occasional 20 amp peak demand without eveR pulling more than 15 amps. Whew, but it worked and never melted a cord since.

Your Problem is that you have a boat size that won't really be heated by a single heater, like mine. If you derate the heater, it will just run constantly. Sometimes that's as hard as cycling on and off as there is no cooling period. Again, once the charger cycles on, you will be pulling significant amperage for a 20 amp outlet. If you can't get a bigger supply and connection, trying to heat will always lead to an iffy scenario eventually.

I finally turned the heaters off completely for piece of mind, but then I had condensation to deal with. Winterizing itself is not a big deal. Thus last winter I finally went with a full time dehumidifier. It pulls much less current than a heater, but the boat stays dry.

Oh how I wish I had 220v 50amp service, but so long as it's 30 amp, or in your case 20 amp, I think you have to seriously consider the practicality of high duty cycle use of that connection and the likelihood you eventually burn down. It's not without serious consideration, that those around you will eventually light off too for the same exact fundamental issue. Rarely is just the one vessel impacted. Saving on moorage only makes sense if the boat survives. Winter boat fires are common and the cause is more often than not electrical.
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Old 02-16-2015, 12:25 PM   #44
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Thanks ghost and Clectric for your advice. I'm going to the marina today to discuss some of this problem. The freedom 20 is set for load sharing with the other AC loads. I have set the two space heaters for their lowest heat settings at 500 amps. They are pretty much on all the time right now. Am I correct with the following calculation: (500+500 watts)/120 volts=8.3 amps? I have a unit on the boat called a circumvent that works well to control the humidity most of the time but cannot keep up with the humidity that we've experienced over the past couple of months this winter-Pineapple Express after Pineapple Express. That said, the boat is not a damp boat at all. I do like the idea of a dehumidifier though. I'll consider that for next year. The "Dries airs" cannot keep up with the event events.

Thanks again for your advice although I'm not presently inclined to change marinas.


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Old 02-16-2015, 12:54 PM   #45
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Trust me, I get it. Quite the imperfect world we deal with. As far as the amps, best to measure. I would have said double that, but at the lower setting thats probably right. Add in the charger and occasional frig, derate the 20cable to 15 and your right there quite a bit.

I would suggest the smart plug, but that only helps the boat end, plus I've seen a few of those melt too (one my own), usually the retrofit plugs. The complete molded cable does not seem to have had that problem. Probably worth going to, or some other upgraded type of connection.

BTW the dehumidifier I scored for free! A buddy of mine got it at the trash on a boat going up for sale, as the brokers like to get everything off. It was a heavy duty marine style unit worth about 1200 too.

So far this winter, its been absolutely super. Last year this time I had mold starting and moisture I never had to deal with before. This year would have been worse. So....cross your fingers but I think the dehumidifier is going to be a real answer.

I do turn up the amperage on the cables, but only while I'm aboard.
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Old 02-16-2015, 12:55 PM   #46
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Oh yeah. Gorgeous boat!
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Old 02-16-2015, 01:12 PM   #47
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I have a unit on the boat called a circumvent that works well to control the humidity most of the time but cannot keep up with the humidity that we've experienced over the past couple of months this winter-Pineapple Express after Pineapple Express.
Ain't that the truth. . I know we live in the "rainy PNW", but this year has got to be one of the wettest I have ever seen. Waves of monsoon like storms marching in off the Pacific.

When all this wet weather gets me down, I just tune into the weather channel and watch the East coast weather reports. I hear the Polar bears are migrating south from Churchill, Manitoba and are roaming the streets of Boston now!!
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Old 02-16-2015, 01:42 PM   #48
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The Smartplug was a good idea, but has suffered a number of dramatic failures. The ones I have seen all failed on the boat end, due to the cable twisting inside of the plug and shorting out the boat end smartplug. Looked like the plastic cable locking mechanism wasn't strong enough to prevent cable twist. Is that how your's failed?

Yes I agree, one piece cable with molded plugs seems to be the way to go, water proof and long lived. As long as the dock receptables are maintained, everything is good. But they're only as good as the marinas dock receptacle. Pig tails are more, open to the weather, sockets and plugs to add resistance to the cable.
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Old 02-16-2015, 02:14 PM   #49
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Yes, Ghost. I will put a clamp meter around the power chord and record real time amps with various devices on the system. The fridge and freezer are individual Novacool DC units and combined draw 11.5 amps at 12 volts DC. The Freedom 20 after being off for a while with discharge to the batteries, when turned back on "spikes" at about 85 amps (~1,000 watts) and then drops quite rapidly down to 60 amps. The two heaters at a combined 1000 watts. My quick calculation suggests a peak load of 2,200 watts or about 18.3 amps at 120 volts with all of these devices on at the same time. Not a lot of wiggle room, that's for sure.


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Old 02-16-2015, 04:02 PM   #50
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If there is a very good condition (like new) live-wire 30 or 50 A electric cord hooked-up to dock and boat with 3' of it dangling in water what is the amount of electric current emitted into water?
Art-- I don't believe a cord in good condition will leak any power into the water if it sags into the water between the dock stand and the boat. But we always pull a cable out of the water if we see it's slipped to be drooping into the water because there is no way for us to know if the cable has a slit or some other wear or failure poinnt that puts water or moisture in contact with the conductors inside the casing.
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Old 02-16-2015, 04:17 PM   #51
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Larry, mine did not short out. I'm not sure about J's, or if you saw that one. On mine, it all held together, it seems that even though the copper was "shiny" it did not conduct well. Funny thing is, that in its melted state, I cut another six inches off the cable, used the same terminals and screwed it all back together and it worked fine again! I just had to use a pocket knife to cut enough of the melted goo away to be able to get a screwdriver into the terminal again. Smart plug has supported these pretty well, though they did get a bit accusing of J before realizing the problem was not user install deficiency. J does not start out by describing what he does for his day job, neither do I though they were bend over backwards helpful when I mentioned it, but then they had personally given me a few for the club, very supportive. I'm not sure I think the thermostat they claim is really working.

But as I said, the molded plugs, I have not seen or heard of a failure. I start to actually wonder whether the practice of putting new Marinco plug ends on the old Marinco cords is actually suffering from the same kind of failure. We always blamed the cheapo plug locking ends, which is certainly contributory, but I start to second guess whether "cutting back to shiny" metal is actually a part of the problem.

If you had seen my shiny metal, still firmly clamped into a goo of melted plastic, you would know what I mean.

I still think the smart plug has a much better mechanism overall.
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Old 02-16-2015, 05:25 PM   #52
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Let us know what your clamp meter reads when you clamp it around you power cord.
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Old 02-16-2015, 06:05 PM   #53
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The dreaded phone call

I'm having trouble interpreting the clamp meter reading. It's a cheap clamp meter. The meter is set at 2/20A~. Of I put it around the heater cord (supposed to be 600 watts) I get a reading of 0.043-0.050. Around the power cord with both heaters and the Freedom 20 on a low state of charge and I get a reading of 0.30. I'm not sure if I'm using it properly. The reading moves around a lot. The voltage on the receptacles is 110 volts AC with the heaters off and 106 volts AC with heaters on. The Freedom 20 is sitting on Accept and showing a low state of charging.


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Old 02-16-2015, 06:38 PM   #54
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You have to put the clamp on ammeter on only one wire of the cable (i.e the black), not the whole thing.
For something like a heater power cord, you need a splitter which splits the hot and neutral without actually splitting the cord.
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Old 02-16-2015, 07:13 PM   #55
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Ok! It's not clear from the instructions!


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Old 02-16-2015, 07:34 PM   #56
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I just talked to the fellow in charge of the maintenance down here and he said they are changing the entire pond over to 30 amp this summer. I suggested he start with Britannia dock while they are building new docks at the other locations.


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Old 02-16-2015, 08:29 PM   #57
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Art-- I don't believe a cord in good condition will leak any power into the water if it sags into the water between the dock stand and the boat. But we always pull a cable out of the water if we see it's slipped to be drooping into the water because there is no way for us to know if the cable has a slit or some other wear or failure poinnt that puts water or moisture in contact with the conductors inside the casing.
I pull em out too. Good dock mates do!

But, I see too many boaters simply walk by and some board boats leaving line sagged into water.
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Old 02-16-2015, 11:16 PM   #58
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I'm not sure I think the thermostat they claim is really working.

But as I said, the molded plugs, I have not seen or heard of a failure. I start to actually wonder whether the practice of putting new Marinco plug ends on the old Marinco cords is actually suffering from the same kind of failure.
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Yes, my main cord is one piece. I have pigtails for the rare marina that doesn't have 30A, but it has been years since I had to use them. I'm confident the one piece, molded plugs to cable setup is the way to go with either Smartplugs or Marinco.

I don't think I saw your failed Smartplug, but i did get to examine a couple of other failed Smartplugs and the thermal coupler did not protect them either and they did twist, short out and meltdown. Smartplug gave the one guy I talked with, some grief initially before offering to send him a one piece replacement cable with molded plugs, but he also had to give them the failed plug. I got to see the plug before he sent it back. I like the lock feature of the Smartplug, but I'm not ready to switch over yet.
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