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Post by servdiv on Sept 24, 2019 17:52:35 GMT
I have two 30amp shore power lines and read that putting in a galvanic inverter will make a difference but am not sure if my 2015 409 has one already?
Also, do you know if the windless runs off the house batteries?
Also does the bow thruster run off both batteries under the V berth and is the motor a 12 v or 24 v motor?
Sorry, I have so many questions...thanks to all...Kevin
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Post by j24sailor on Sept 25, 2019 5:02:49 GMT
I have two 30amp shore power lines and read that putting in a galvanic inverter will make a difference but am not sure if my 2015 409 has one already?
Also, do you know if the windless runs off the house batteries?
Also does the bow thruster run off both batteries under the V berth and is the motor a 12 v or 24 v motor?
Sorry, I have so many questions...thanks to all...Kevin A galvanic isolator is a must have. I think most 409s do have one. Ours is in the back port locker right beside where the shore power plugs in which is where it should be (close to the shore power). It usually has a lot of "flukes" to let heat off but not all do but that may help identify it. The windlass is usually run off the house batteries. I have bow thruster envy so can't really answer this question. However if you look and see the batteries connected I would assume they both power the motor as there isn't much else up there that they would power except maybe an anchor wash pump, but that would not usually have its own battery. If you see them wired in series or parallel will tell you if they are wired in 24 or 12V plus if you can see the motor for the bow thruster it should indicate whether it is 12 or 24V. So many questions which are great and keep them coming that is what the forum is for. Is this boat new to you and if so congratulations. We love our 2011 409. James
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Post by servdiv on Sept 27, 2019 17:56:25 GMT
Thanks, my first big sail boat, built in 2015 but in the water in 2016 with 210 hours on the engine so kind of new...
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Post by moonshadow on Sept 28, 2019 0:56:18 GMT
My 2013 SO 469 did not have a galvanic isolator. The maintenance shop manager at the local Jeanneau dealer insisted that this is not necessary with US marinas and boat wiring. But I’m not convinced. So I am in the process of installing one now. Seems pretty straightforward to install. And with an aluminum saildrive it makes sense to have it.
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Post by servdiv on Sept 30, 2019 11:58:48 GMT
Thanks, I agree, putting one on this weekend just to be safe with my folding prop and sail drive...
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Post by Trevor on Oct 6, 2019 12:24:28 GMT
Hello,
A galvanic isolator is of use if you are at a marina with other boats and you are plugged into power. As an example, if you put dissimilar metals in a glass of salty water in your kitchen, say a silver spoon and a strip of aluminium foil, and put a DC meter across the two metals, you will read a voltage. That is the natural voltage of those metals as shown in a table called the galvanic series. If you electrically join those pieces of metal together you will encourage a current to flow proportional to how far apart those metals are in the galvanic series. The least noble of those metals will corrode as a result of that current. If you leave it in the glass of salty water long enough it will corrode away.
When your vessel is plugged into a power outlet at a marina ( not even necessarily switched on ) your expensive underwater metal bits are connected to the underwater metal bits of everyone else’s boat. This is universally true anywhere in the world that uses the concept of a safety ground conductor. To my knowledge everywhere. That means you have repeated the glass of water in your kitchen experiment but on a grand scale.
It doesn’t matter what the supply voltage is, how many phases or what country you are in. It is much simpler than any of those things. It is simply that the ground of your boat is connected to the ground on one or many other boats. By doing this, if your underwater metal bits are any different to any of the underwater metal bits on any other boat you have created a giant battery. The boat with the least noble metal will suffer first.
The voltages developed by metals on the galvanic scale are small. The job of the galvanic isolator is to block those small DC voltages from allowing current to flow but still allow large AC current to flow in the event of an electrical fault so the ground connection can do its job.
If your boat lives on a swing mooring, a galvanic isolator is of no use. If your boat is in a marina and plugged into the power outlet, it is a good idea.
I hope this may help demistify how this gadget works.
Trevor
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Post by moonshadow on Oct 6, 2019 14:28:33 GMT
Thanks Trevor. I completed installing my promariner galvanic isolator a few days ago very easily. I feel better having it in place and working. I had my zincs checked when I finished installation so I can still have a baseline and see what current condition compares to when I do my spring zinc replacements.
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Post by johannes on Oct 7, 2019 9:16:42 GMT
Having a galvanic isolator doesn't hurt, but it may be of no use at all. You should not trust it. It blocks currents that are induced by ground voltages below about 2 V. But in some places ground voltages are way above that, sometimes up to 15-20 V. In those cases a galvanic isolator makes no difference. The Swedish Cruising Association recommends against relying on galvanic isolators in Swedish waters because the base rock in most places is sufficiently isolated from the safety ground at the electrical substations that the ground voltage fluctuation will more or less always be above 2 V. The best way to avoid galvanic corrosion is to use an isolating transformer. They are heavy and expensive though. Alternatively, it is possible to have a switch that disconnects the safety ground wire from the boat's electrical system. This may be illegal in some jurisdictions. If you go that route, it is absolutely necessary to have a ground fault circuit interrupter (which you should have anyway). Here are more details (in Swedish): batteknik.se/2010/13297_foredrag.pdf
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Post by captbillh on Oct 17, 2019 18:04:33 GMT
Before you install a galvanic isolator check that the AC ground(green wire) is connected to the DC ground. Usually Jeanneau does NOT connect the 2 grounds together. Then in this case the isolator is not "doing anything". A continuity check would show an "open" vs. "a short". The is the caae with my 2015 409.
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Post by Tafika II on Oct 18, 2019 16:19:18 GMT
Captbillh, Can you expound on the location of the Green wire and where it should be grounded. I believe mine GI is OK, but your statement leads me to want to recheck it.
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Post by mred25234 on Oct 19, 2019 11:16:33 GMT
Before you install a galvanic isolator check that the AC ground(green wire) is connected to the DC ground. Usually Jeanneau does NOT connect the 2 grounds together. Then in this case the isolator is not "doing anything". A continuity check would show an "open" vs. "a short". The is the caae with my 2015 409. Can you show us where you made that connection of the two grounds?
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Post by ForGrinsToo on Oct 20, 2019 16:32:31 GMT
Here's a nice summary of the shorepower, lightning, and dc systems grounding recommendations from ABYC: www.westmarine.com/WestAdvisor/Marine-Grounding-SystemsAccording to the ABYC, the boat’s bonding system, the DC negative system (which includes the engine block and battery negative) and the AC safety ground all should be connected and remain at the same potential. The resistance between any two components in this system should not exceed 1 Ohm. (It’s important to note that any bonding wire attached to the engine block must be sized to safely carry full engine cranking amperage.) A galvanic isolator is essential in "hot" marinas or where "hot" boats may be nearby. If everything is wired properly, they are not necessary. If everything electrical has been installed by a properly trained and certified electrician, it would be a perfect world. However.... In general, it is a good idea not to leave shorepower attached when it isn't actually needed. If you have a galvanic isolator, the risk is dramatically reduced. We usually just disconnect. Geoff
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Post by vasko on Oct 21, 2019 4:43:23 GMT
You can just by a electric cable extension with galvanic isolator - no need to install one - or at least this is what I have done
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Post by Trevor on Oct 21, 2019 13:40:30 GMT
Hello to Galvanic Isolator enthusiasts, One of the great advantages of this group is the wisdom of the crowd. Sometimes just when I think I have a working knowledge of something, one of the members here says something that sends me right back to the drawing board. One such member is capbillh and I thank him for the post where the fundamentals of the ground wiring of the Jeanneau yacht is outlined in the post below. Before you install a galvanic isolator check that the AC ground (green wire) is connected to the DC ground. Usually Jeanneau does NOT connect the 2 grounds together. Then in this case the isolator is not "doing anything". A continuity check would show an "open" vs. "a short". The is the caae with my 2015 409. Reading capbillh's post had me running around with my multimeter to prove him eerr..eerrr......RIGHT!!!! When I first read this I was sure it was wrong. I has assumed (completely wrongly ) that the mains ground and DC ground were joined. I was so sure of this that many years ago I had shelled out good money for a Galvanic Isolator and installed it in a completely isolated ground conductor!!! Hahahahah The isolated ground wiring means my Galvanic Isolator does absolutely nothing. (anyone want to purchase a slightly used Galvanic Isolator?) That means that my SO42DS cannot suffer from Galvanic Corrosion as a result of being in a marina and forming a great big battery cell with other yachts. The isolating feature of the Galvanic Isolator is simply not required. I have some other thoughts for consideration in response to Geoff's comments about "hot marinas". If we define a "hot marina" as one where one or more boats are leaking DC currents into the water, a Galvanic Isolator will not help. The leakage of DC currents from a source like batteries causing metal to corrode is called "leakage current corrosion" or "electrolysis". The spontaneous generation of DC currents by dissimilar metals being immersed in an electrolyte (salt water) is called "dissimilar metal corrosion" or "Galvanic corrosion". The Galvanic Isolator is effective in stopping the small currents generated by small voltages arising from Galvanic potentials, not large voltages presented by ships batteries. If we moved two yachts from a marina, rafted them up in a bay somewhere , joined their mains earth green wires together (provided they were tied to DC ground) the dissimilar metals between the two yachts would form a cell and a conductive path for the Galvanic corrosion would be established. If we installed one galvanic isolator in one of those earth wires, that galvanic corrosion current would stop. In a "hot marina" however the voltages would exceed the blocking capability of the Galvanic Isolator which is designed to block very small galvanic voltages, not electrolysis causing voltages. What an interesting topic! I hope this helps a bit. Anyway, time for me to sell my Galvanic Isolator and buy some beer with the proceeds! Regards, Trevor
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Post by ForGrinsToo on Oct 21, 2019 19:10:45 GMT
As is frequently the case, Trevor digs deep and comes up with the facts.
For me, the greater concern is that in the marina wiring, the ground and the neutral are tied together at a breaker box, not at a pedestal. That point may be several hundred feet from the pedestal where you and your neighbor find your grounds tied together and your neutrals tied together creating just the sort of cell that Trevor describes. (12 ga copper has a resistance of about 1.6 ohm/1000 feet). If one of the boats was incorrectly wired...
Related, pedestal breakers are rarely GFI. I kind of wonder why that is.
A "hot" marina is one where voltage (AC or DC) is getting into the water because something is incorrectly wired somewhere.
I was surprised to see the ABYC requirement to tie the shorepower earth to the DC ground aboard. I expected, as CaptBillH said and Trevor found, that they would be isolated. As I am not registered ($$) with ABYC, I can't get into documentation deeply enough to understand the rationale.
Vasko correctly points out that a galvanic isolator could be in the shorepower cord (does anyone make a marinized version?), rather than installed aboard, when it is thought to be needed. It is worth considering that an isolation transformer is actually the better way to go, but they tend to be much more expensive than galvanic isolators, not to mention larger and heavy. I'm going to stick with disconnecting when not in use...
Geoff
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Post by MalcolmP on Oct 22, 2019 6:25:21 GMT
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Post by wildfire on Oct 22, 2019 10:39:15 GMT
Just reading the above thread I do have some slight concerns about some of the comments made regarding separating the boats AC and DC ground systems. What matters from an electrical safety point of view is that in the event of a fault on the AC system there aren't large chunks of metal work on the boat which could potentially become live at 230V AC, especially if these are immersed in the water. There are lots potential failure mechanisms which could allow, for example, the whole engine block and prop shaft to become live, a cable rubbing through, a fault in the DC charger etc. In these situations if the engine block is at earth relative to the incoming supply (via a nice big earth connection to your incoming AC earth) then the RCD will trip within 30mS and it's unlikely harm will be done. If you don't have an adequate earth then you would be creating an electric field potential in the water between your prop shaft and the nearest bit of earthed metal in the marina. This could kill any-one in the water and it has happened in the past. The IET wiring regulations in the UK (BS 7671) include marinas as a special location, unfortunately the regs aren't free to use but there is a edition of wiring matters available on line which discusses the ways of achieving electrical safety, see electrical.theiet.org/media/1638/marinas-and-similar-locations.pdfIf you look at Figure 1 this shows several means of achieving electrical safety on the vessel, I'm really discussing the option shown at the bottom of the Figure which is the typical situation used for leasure craft in the UK, isolation transformers aren't seen that often but they are detailed in the frst 2 options. So you have now connected your AC and DC grounds to achieve electrical safety but then your anodes on your prop shaft are now connected to every-one elses underwater metal work via the earth system on the pontoon. Assuming you want to provide galvanic protection for your own boat only this is why you need a galvanic isolator in your incoming supply. It has a some back to back zener diodes which block the very low currents assoiated with galvanic corrosion but in the event of a fault will allow the fault current to flow and trip the RCD / MCB. There are few other considerations about earth cable sizing, this article provides a bit more background www.bluesea.com/support/articles/DC_and_AC_Circuit_Wiring/101/Grounding_and_Circuit_Protection_for_Inverters_and_Battery_Chargers
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Post by ForGrinsToo on Oct 22, 2019 13:56:49 GMT
It's worth noting that each of the configurations in Figure 1 utilizes an isolation transformer; the last being shore-based and something I have never noticed at any US marina. electrical.theiet.org/media/1638/marinas-and-similar-locations.pdfI have not yet found an in-line galvanic isolator of the sort Malcolm describes, with a US pin-out. In my view, the 36i does not have a really good place to install a galvanic isolator, and a cable-based system would be a nice solution. If anyone knows of such a device, I would like to hear about it. Geoff
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Post by wildfire on Oct 22, 2019 15:34:42 GMT
Geoff,
Yes your right - I should have looked a bit more carefully at Figure 1. The key point is still that the AC and DC grounds must be connected together on the boat.
Richard
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Post by ForGrinsToo on Oct 22, 2019 20:17:20 GMT
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Post by Trevor on Oct 23, 2019 0:42:18 GMT
I have read wildfire's comments and must admit at first glance I totally agree. I have really struggled with this since learning of the isolation of the mains and DC ground on my yacht. I would like to make a couple of comments though in relation to my musings on this subject. Just t clarify, when I use the term "RCD" is stands for "residual current device" which compares current from active and neutral and trips if they do not cancel out. In other words any current flowing to earth (like through a human being) causes an imbalance and trips the breaker. These are fitted to all marina power supplies at the supply pedestal on the dock in Australia. We also have one as the input breaker on our yacht. 30mA is the commonly used trip point.
1. The mains powered equipment on my yacht is very segregated. By that I mean it is an isolated island in a big plastic floating container. All devices seem to be double insulated and earths are carried through to each item. Few mains powered items exist, water heater, battery charger (switch mode power supply isolated by a transformer) and power outlets. If we have a fault condition where the casing of the water heater or battery charger become live, the shore based RCD will trip or the RCD on the input to the yacht. In Australia, I am pretty sure all outlets feeding boats need to be RCD protected. In the event that somehow the engine becomes live, the current flowing to the seawater would trip the RCD, either on the boat or on the shore power pedestal. It may not trip as emphatically as if the engine is connected to mains earth but it will trip the same as if a person is being protected by a leakage path to ground through their body.
2. We spend quite a lot of time in a caravan. When we plug our caravan into a power outlet at a caravan park, we do not drive an earth stake into the ground just to be sure. We rely on the earth being carried through from the pedestal and rely on the RCD in our caravan and the RCD on the pedestal feeding us.
I am aware that in the past, prior to the use of RCD devices, leakage of mains voltages into seawater would be hazardous to swimmers. I think that in jurisdictions that have a legal requirement for RCD protection, these concerns are minimised. Happy to hear a contrary view but 30mA (the trip point for many RCDs) needs 8,000 ohms of resistance. Surely the resistance of seawater to mains ground is orders of magnitude less than this.
So while I agree with wildfire instinctively, I have really tried to rationalise if my concerns are real or not.
A possible suggestion from johannes to disconnect the earth wire from the yacht did concern me, although it did have the caveat that "it may be illegal in some jurisdictions". It certainly would be illegal in Australia. I certainly would not advocate removing the earth connection from mains powered devices under any circumstances.
I can't see the picture posted by Geoff (ForGrinsToo) in his last post but would like to see it. Like Geoff, I have not known of isolation transformers to be installed in dockside pedestals at Australian marinas.
It could be argued that if we sail into jurisdictions that do not require RCD protection on the dock, we may be in an unsafe environment by not having DC ground connected to AC ground but our yacht has an RCD next to the inlet socket so RCD protection is still assured.
Regards,
Trevor
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Post by johannes on Oct 23, 2019 6:58:34 GMT
Trevor, I agree with most of what you write. Just a few things: All devices seem to be double insulated and earths are carried through to each item. I am fairly sure your water heater is not double insulated. Usually this is the weak point on boats, as most other equipment is double insulated and does not require protective earth. A possible suggestion from johannes to disconnect the earth wire from the yacht did concern me, although it did have the caveat that "it may be illegal in some jurisdictions". It certainly would be illegal in Australia. I certainly would not advocate removing the earth connection from mains powered devices under any circumstances. I would not generally recommend it, it is something you might consider if you know what you are doing. If the water heater is the only device on board that is connected to protective earth, and there is an RCD that essentially serves the same purpose, the risk of disconnecting PE is low.
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Post by Trevor on Oct 24, 2019 1:41:49 GMT
Hello johannes,
Yes as I read your comments I agree with you. Upon reflection I would doubt the water heater is double insulated.
Regards
Trevor
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Post by wildfire on Oct 27, 2019 21:32:54 GMT
The resistance of the water may or may not be enough to trip a 30mA RCD, particularly if the water in the marina has more of a fresh water than sea water content. Interestingly in this case a person in the water is more at risk than in seawater, this becomes an important consideration for divers using underwater equipment, the International Marine Contractor's Association have a specific set of guidelines which discusses this.
At the end of the day it's all about probability of something going wrong, for example I don't have an earth fitted to any of the thru hulls on my boat as there are no cables any where near them and it's not credible that they could become live. However there are many realistic scenarios which could lead to the engine block becoming live through the DC wiring, e.g. a fault in the battery charger or a loose wire in the combined AC - DC distribution board. I don't really know how Jeanneau have run the AC cables, I wouldn't be surprised if they run together with some DC cables giving another mechanism for a connection in the event of a fault.
This is quite a complicated topic and there are lots of differing opinions however most of the standards / legislation I have looked at opt for recommending or requiring the AC and DC earths to be bonded so this is what I have gone for.
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