ELCIs and galvanic isolator

[bglad]

Agreed but you are plugged into a 240/50 pedstal that is capable of delivering 100 amps at 120 volts so you wan't be tripping that pedestal with 60 amps as you were thinking in the section of your post I quoted.

[CaptFrankM]

Originally Posted by bglad

Agreed but you are plugged into a 240/50 pedstal that is capable of delivering 100 amps at 120 volts so you wan't be tripping that pedestal with 60 amps as you were thinking in the section of your post I quoted.

Sorry if I have somehow confused you. This is not a 240 volt pedestal. It is a 120 volt, 50 amp pedestal.

[bglad]

My bad. When I went back and reread your post you say there is no 240 volt input. From what I have seen it is very unusual for a marina to be using 120/50 amp on their pedestal. Current state of the art is 240/50 or 2 x 120/30 for the reasons you stated. Can be a little confusing since the two 50 amp fittings look the same except the 240 volt version has two poles with the little tabs instead of just one. Just depends on what part of the world you are in.

[CaptFrankM]

I agree. These are brand-new pedestals - installed within the last month - and I thought the same thing. Why put in one 50 amp connector instead of two 30 amp ones? I was told that they were expecting most "new boats" to use more than 30 amps. Left unsaid was that it was cheaper to put in one 50 than two 30s.

It does look to me like you could plug a 240 volt plug into a 120 volt socket, but not the other way around. It also seems to me that a single pedestal could be wired for 240 volts, 100 amps, and broken down at the pedestal. One leg would be 120/ 50, the other leg also being 120/50 and the leg-to-leg being 240. I seem to remember that my mother's house was wired that way. The stove and the dryer were 240 volt. Everything else was 120 volt. Oh, well.

Bottom line - I have 120 volts, 50 amps to work with.

[pbiJim]

Originally Posted by CaptFrankM

I run a Marinco 50 amp to 2x30 amp splitter (PN 152AY). All the splitter does is break the power into two connections. It does no load splitting.

That sounds an awful lot like load splitting to me. It also sounds like you have a 30-amp plug & therefore probably a 30-amp wire protected by a 50-amp breaker. Ground fault or not, I don't think that is the best situation to put yourself in, especially as an intended standard practice.

I think that you probably have multiple problems with this installation. Dave has previously been kind enough to provide drawings of the kind of wiring system that would probably suit you well. You might want to search some of his previous posts.

Alternately, you may wish to enlist the services of a local marine electrician. There may be additional issues that you have not listed because you did not recognize them as potential problem areas.

[CaptFrankM]

Jim, please don't take this the wrong way but exactly what do you base your opinion on?

First off, you are questioning the wiring in the pedestal, despite my statement that this was a brand new installation. Why would you assume that the contractor hired by the marina would deliberately violate the electrical code and install a 50 amp breaker on a 30 amp line? Or that the inspector who signed off on the installation would have either allowed the violation or not noticed it?

Next, your comment on load splitting is wrong, or should I say, you misinterpreted what I meant. The Y cable does not restrict the current flow to either leg. It merely allows to independent loads to attach to a single socket.

Finally, I have been doing electrical wiring for about two decades. My issue was not with the wiring, as I said in my first post. It is with the ELCIs and their relationship with the galvanic isolator that I was questioning. Since the ELCI technology is relatively new, I wanted some input on that subject from someone with some experience to tell me if there was some particular issue that I was missing. I had already identified the mixed neutral buss as the probable source of the problem and Dave confirmed that for me.

What I did not want or need was random uninformed sniping comments. As my Southern friends say, don't dip in the kool-aid if you don't know the flavor.

[smac999]

Originally Posted by CaptFrankM

Jim, please don't take this the wrong way but exactly what do you base your opinion on?

First off, you are questioning the wiring in the pedestal, despite my statement that this was a brand new installation. Why would you assume that the contractor hired by the marina would deliberately violate the electrical code and install a 50 amp breaker on a 30 amp line?

what size is the wire in your 30 amp shore cord? what size is the wire from the boats shore plug to the 30a main breaker? and how long is that wire inside the boat?

it's probably all 10awg for a 30amp circuit. and all that wire is being protected by the 50a shore breaker. that was his point which is correct

however it's commonly done and the chances of something happening between the dock breaker and the main breakers is small. (chances are the problem would be a short and just trip the 50A anyways)

Finally, I have been doing electrical wiring for about two decades. My issue was not with the wiring, as I said in my first post. It is with the ELCIs

the problem was not with the ELCIs as you state. the problem is with your wiring. every boat with 2 lines should have the N's separated. weather it's normal breakers or ELCIs. had it been wired properly. you would not have had issues.

and the inverter loads should be on a 3rd N bus connected only to the output N of the inverter.

No, I don't need two switches for the input and I am not running the two lines together. I am using a Blue Sea AC Rotary Switch (PN 9093), which takes the two lines in and keeps them separate.

that is a quad pole and just fine. I have seen people tie 2 lines into a double pole before in parallel so I asked.

[pbiJim]

Originally Posted by CaptFrankM

Jim, please don't take this the wrong way but exactly what do you base your opinion on?

First off, you are questioning the wiring in the pedestal, despite my statement that this was a brand new installation. Why would you assume that the contractor hired by the marina would deliberately violate the electrical code and install a 50 amp breaker on a 30 amp line? Or that the inspector who signed off on the installation would have either allowed the violation or not noticed it?

Next, your comment on load splitting is wrong, or should I say, you misinterpreted what I meant. The Y cable does not restrict the current flow to either leg. It merely allows to independent loads to attach to a single socket.

Finally, I have been doing electrical wiring for about two decades. My issue was not with the wiring, as I said in my first post. It is with the ELCIs and their relationship with the galvanic isolator that I was questioning. Since the ELCI technology is relatively new, I wanted some input on that subject from someone with some experience to tell me if there was some particular issue that I was missing. I had already identified the mixed neutral buss as the probable source of the problem and Dave confirmed that for me.

What I did not want or need was random uninformed sniping comments. As my Southern friends say, don't dip in the kool-aid if you don't know the flavor.

I don't take that the wrong way & I apologize if my comment sounded like sniping.

I believe that your splitter splits the load. Perhaps I misunderstand how you have the rest of your wiring configured or perhaps I don't understand what you mean by splitting.

The 50 amp outlet on the dock is probably protected by a 50 amp breaker. When you go through your splitter that has 2 30 amp outlets, you then have a pair of 30 amp outlets that are presumably attached to 30 amp wire, being fed from that 50 amp breaker. If that is true, then the 30 amp wires that comes from those 30 amp outlets are protected only by the 50 amp breaker in the area of the wiring before your 30 amp breaker. Perhaps I misunderstand how you have your wires configured, but it sounds likely to me that you have an improperly protected ampacity of wire in at least 1 area.

Again, I apologize if misunderstand your configuration or if my choice of wording was not the best.

Please explain to me what flavor of kool aid you are serving if you still believe that I have made an incorrect assumption. If you simply prefer that I not take another sip from your kool aid jug, simply tell me so & I'll be happy to go away quietly.

Jim

[CaptFrankM]

OK, Jim, I see where we are getting off track with the splitter concept. When I say that the Y is a "splitter", I mean that it is a "line splitter." It is simply taking a single line and dividing it in two. When I see the term "load splitter," I think of an electronic device that takes the current requirements of a single load (or multiple loads that can be treated as one) and balances the requirements of that single load across multiple sources. For example, Honda builds a circuit into some of its small A/C generators that allows two generators to run in tandem to supply power for a load too large for one generator to handle. To my mind, that circuit is a "load splitter" - it splits the load, not the line.

I also see your point with the 50 amp breaker/30 amp wire, but I have to disagree with the thought process. You are assuming, I think, that any single 10 gage line would pick up a load greater than 30 amps but less than 50 amps between the 50 amp breaker and the 30 amp breaker. I cannot conceive of a situation where that might occur. It is not possible to connect the power cord directly to a load, other than the boat itself, because of the cord ends. I suppose that, if I removed the end of the cord and wired it directly to some 40 amp load, it might be possible for that to occur, but that would require a monumental disregard for the system requirements. Unfortunately, I am not sure that the system could be designed to override stupidity.

It could be argued that "it might happen," but to use that logic, every electrical socket in a house would be wired with 2/0 gage wire, because the house's main breaker is rated for 200 amps and "it might happen" that something could cause a load just under 200 amps along that path.

I suppose the shortest answer that I have is that, in the opinion of the engineers who designed these systems and who write the codes, the possibility of a situation where one line would end up carrying more than 30 but less than 50 amps is so small as to be an acceptable risk. Otherwise, the code would be written in a way that would prevent this from happening and there would be no boats with multiple shore power connections.

As for the flavor of the Kool-aid, this is mine and I try to live by it. I try never to assume anything about a person's post. If there is a specific question to which I have a specific answer, I will do my best to provide that answer, along with the reasons why I believe my answer is related to the question. I try not to presume that I know anything about the person's experience, level of knowledge or ability, other than what has been specifically presented.

In this case, I laid out all of the information I had available, explained the symptoms that I was seeing to the best of my ability and then presented what I considered to be the possible problems. I then asked if anyone saw something that I was missing in my analysis.

My specific problem was that the ELCI breakers would not close. I believed that this may be related to the fact that, unlike the way the boat had been initially wired, the neutral buss may now need to be separated by input line. This had not been a problem before the introduction of the ELCI breakers and, in fact, the boat had run this way for years without a problem.

So, I was looking for a specific answer to that specific question. Pointing out that some people might consider that the shore power cable arrangement might not be optimal did not address that problem. The shore power cord arrangement is not illegal, it is not outside of code and, to the best of my knowledge, does not violate any ABYC requirement. It may not be the way that someone else does it on their boat - but it is the way it is on mine.

If you had said, "By the way, I don't know if you had thought about this, but there is a possibility that the use of two 30 amp cords from a single 50 amp breaker may cause a problem. Here is an example of that happening and here is why I believe that doing this other thing might be a better option," I would have thought about it, looked into the example you provided and made a reasoned assessment of the possibility of the same thing happening to me. If you had pointed me toward an ABYC requirement or some other engineering-based rule setting organization's opinion on the matter, I would have looked into that.

However, what I have found to be the case - and I apologize for making it seem like you fell into this category when apparently you did not - is that there are a significant number of people on these forums who consider themselves experts on subjects and, therefore, make pronouncements regarding "how things should be done." They do not back up their pronouncements with any data. It is simply that "this is the way I would do it, so everyone should do it that way."

So, please, if you have a position that you feel is germane to my question, you have a specific comment that you would like to back up with some experience or reference to a source that I can evaluate and you feel that it would be helpful to my particular situation, I would appreciate your input. I will freely admit that these new ELCI breakers are not within my frame of reference and, while I can do my own research, I would love to get specific information from people who have worked with them.

However, to those individuals - and again, I am not classing you in this group - who feel they need to make a comment simply to make a comment, I ask that they please go and find someone else's thread to hijack. I don't have time to sift through random attacks on how I did what I did on my boat.

Thanks for your patience,
Frank

[Colin A]

Frank,

Just one quick question, it may be the wording in the first post. Are the ELCI breakers in between the shore inlets and the rotary switch or after the rotary switch?

Based on what I read in your description I would have to agree you need to split the neutrals on the two incoming shore powers.

[CaptFrankM]

After the rotary switch. I initially had intended to put them before the switch, so that the switch would be protected, but then I read that you shouldn't have another source downstream of the ELCI breakers. Since the point of the rotary switch was to connect the generator, I decided to put it upstream of the ELCIs.

[Colin A]

Another question,
Is the generator wired as 240/120VAC as in two hot legs of AC with a neutral? As I recall ABYC does not require generators to have ELCI protection only shore power. I don't think your current setup will cause issues with this but I haven't seen any tests done with a generator feeding marine ELCI units. I know on the installations I've seen at several boat builders ELCI's were all connected in the shore line inputs only. Not sure there are any issues there but it's something to keep in mind if you get tripping while running on the gen.

[CaptFrankM]

I admit, Colin, that the ELCI after generator idea did not make much sense to me (By the way, it is set up as a 120 volt, single hot leg). After all, if the ELCI was upstream of the rotary switch, the ELCI should never "see" the generator, to my mind. But, as I said, the documentation I received with the breakers specifically said that they should not have another source downstream of them. The problem was that, in most of the things that I read, there was no discussion about having ELCIs and a generator.

The other thing in my mind was that, if I ran the ELCI breakers upstream of the rotary switch, I would still want another set of 30 amp breakers downstream of the rotary switch, since I would want a 30 amp protection on each line, downstream of the switch and the generator output breaker, which is a 50 amp breaker.

Finally, the ABYC requirement 11.11.1.4 says that the ELCI breaker "shall be readily accessible." To me, that meant that I didn't want them in the engine room, I wanted them on the A/C power panel in the galley. If I added them upstream of the rotary switch and then added another set of 30 amp breakers downstream, I would have had to increase the size of the power panel.

I did read one article about an ELCI refusing to run on a portable generator, but it had something to do with the fact that the system wasn't grounded correctly. The person who wrote the article basically said that the problem was not the ELCI, it was that this particular type of generator should "never be used on a boat." However, since I am using a permanently installed marine generator, I don't see that as a problem.

I will say that, if I do run into problems with the ELCIs tripping on the generator, I will move them upstream and into the engine room. There is, after all, sense to all things, as my mother used to say.

[pbiJim]

Frank,
I'm sorry that I made you feel it was necessary to write that much in response to my posts. It shouldn't be that way.

My original post was in regards to a possible source of your ground fault trip coming from your Y splitter. Dave later identified another probably source based on another part of your description that I didn't fully picture in my head. I think that you may have multiple ground fault paths that are tripping out your new breakers.

By the way, I don't know if you had thought about this, but there is a possibility that you may have a potential for excessive unprotected ampacity in a 30 amp line. I may be misinterpreting how you have your Y splitter set up, but if it is set up the way that I am picturing, then you probably have pair of 30 amp wires protected by a single 50 amp breaker, which is generally a no-no. Under NEC this sort of thing is allowed inside of a breaker panel for a short distance when feeding a smaller breaker or fuse, but I do not believe that it is allowed for cables that exist outside of a closed cabinet. I can't quote you title & verse from the NEC or ABYC on that. I'm not that much of a book worm & I don't have access to the full current ABYC standards. I think that you might want to look into it though. It is a possible source of an overload. As an example, an overload could occur if one of your 30 amp breakers trips & the cable on the other 30 amp cable is chafed to the point of a partial short. In that event, a 30 amp cable could potentially carry up to 50 amps before the upstream breaker trips. That would constitute a fire hazard.

I have seen some scary do-it-yourself wiring in the past & perhaps I am now oversensitive to that possibility. When I saw the possibility of an under protected 30-amp cable, my knee jerk reaction was to suggest that you find a qualified electrician. Perhaps that was an excessive response on my part. I don't know your level of competence in electrical wiring. I apologize if I overreacted.

I hope that you find a solution that works well for you.

Regards,
Jim

[pbiJim]

Originally Posted by CaptFrankM

I admit, Colin, that the ELCI after generator idea did not make much sense to me (By the way, it is set up as a 120 volt, single hot leg). After all, if the ELCI was upstream of the rotary switch, the ELCI should never "see" the generator, to my mind. But, as I said, the documentation I received with the breakers specifically said that they should not have another source downstream of them. The problem was that, in most of the things that I read, there was no discussion about having ELCIs and a generator.

An elci should work just as well off of a generator as any other primary power source. Per NEC, the output of a generator is the same as a service entrance & therefore neutral should be connected to ground at that point & at no other point thereafter. I don't know the position that ABYC takes on that subject.

If your switchgear disconnects shore power when it connects the generator, I see no problem with having the generator upstream of the elci. Putting a second power source downstream of an elci will invalidate it's function. I believe that ABYC considers this issue to be negligible in the case of your generator because the source of power & the return leg from an on-board generator are both on the same boat & therefore it is unlikely for this system to cause the water outside of the boat to reach a voltage gradient above the 2 volts per foot that they consider lethal. When one leg is on the boat & the other leg is on shore, then they get worried.

I don't believe that anyone looks to prevent you from voluntarily using an elci after a generator on a boat, but I also don't believe that anyone requires it.