Isolation Transformer - specific recommendation?

[mvweebles]

My electrician asked about an Isolation Transformer. Any specific recommendations? 30A/120V service on Weebles.

As always, many thanks in advance - Peter

 

[DDW]

Victron?

There are also toroidal ones that are lighter and take less space, but the topology does not meet the letter of ABYC regs (even though it is probably just as safe).

 

[twistedtree]

ACME/Hubbell makes a nice line that meet all the marine requirements or separate grounds for primary and secondary.

 

[mvweebles]

So the 3600w version is huge. Size of a large inverter.

Victron Energy Isolation Trans. 3600W 115/230V https://a.co/d/fImLT2p

Maybe I should rephrase my question. What do I really need? Over next 2 years, I'll probably be in a marina half the time. After that, will be in my slip where I have the only power connection. Even them, will not use it much due to large solar array that makes me net-zero.

Thoughts? Maybe a simple galvanic isolator? I'm out of my depth on this one.

Peter

 

[sunchaser]

So the 3600w version is huge. Size of a large inverter.

Victron Energy Isolation Trans. 3600W 115/230V https://a.co/d/fImLT2p

Maybe I should rephrase my question. What do I really need? Peter

If your ground wiring has been done correctly maybe you don't need an IT. As you note, they are big. Some are noisy and they are heat generators.

Six years ago our vessel had compatibility issues with new GFIC dock wiring. A very smart marine electrician suggested a ground wiring re-do. This was done and the IT need evaporated.

Also, we now have an inverter bypass that takes care of the few instances when GFIC docks prove problematic.

 

[mvweebles]

If your ground wiring has been done correctly maybe you don't need an IT. As you note, they are big. Some are noisy and they are heat generators.



Six years ago our vessel had compatibility issues with new GFIC dock wiring. A very smart marine electrician suggested a ground wiring re-do. This was done and the IT need evaporated.



Also, we now have an inverter bypass that takes care of the few instances when GFIC docks prove problematic.

I called a good friend who bails me out of conundrums. He has a similar setup as me - his is a Roughwater 37. He said same as Sunchaser - no need for an Isolation Transformer, but perhaps a Galvanic Isolator. My electrician has only marginally better English skills than my Spanish skills, so when I asked him, he confirmed galvanic isolator.

I ordered the Newmar i30 from Hodges. $219.

Thanks all

Peter

 

[DDW]

Isolation transformers are large and heavy.

One question to ask on the Newmar: is it failsafe as required by the newest ABYC (and therefore potentially surveyors)? When I was looking for one, many of them were not. Newmar doesn't seem to say, only references some ABYC gobbledegook.

The issue with diode isolators is they tend to fail open, leaving your ground system floating. It is supposed to fail shorted which defeats the galvanic purpose, but at least keeps the safety ground connected. When I was looking, the Promariner for example met this, the Victron did not. Did not see the Newmar at that time.

 

[boomerang]

On our last boat, a 34 Mainship with a single 120v 30A system, I installed an Acme 3kVa unit and wired it as an isolation transformer. Did we need it? Probably not and could've gotten by with a galvanic isolator. It sure was nice knowing our boat was protected from stray currents and being able to pull up to any GFI-equipped marina and knowing there wasn't going to be an issue. I don't think the thing weighed much over 50 pounds , which actually helped us to trim a slight list our boat had, anyway.

 

[CharlieJ]

@OP:
If the GI has not been constructed and third party tested to ABYC A-28, it is not compliant and may or may not be fail safe. The Newmar unit referenced does not appear to be ABYC compliant. I would recommend against installing it.

 

[mvweebles]

@OP:
If the GI has not been constructed and third party tested to ABYC A-28, it is not compliant and may or may not be fail safe. The Newmar unit referenced does not appear to be ABYC compliant. I would recommend against installing it.

Thanks. I have ordered it, but for future reference, how would you know if it is/is not ABYC compliant? Their literature strongly suggests it is. But what specifically should a buyer look for?

From Newmar Tech Spec sheet:

The GI is suitable for use with 115 or 230 VAC circuits up to 30 or 50 amps, depending on model, and has been engineered to conform to the latest ABYC (American Boat and Yacht Council) Standards pertaining to boat wiring. These standards specify that a galvanic isolator must be capable of carrying 135 % of the rated shore power current, while maintaining a maximum exterior surface temperature of 90° C, in the event of an AC fault condition aboard the vessel.

Peter

 

[CharlieJ]

#10
As I said, it has to have been built and tested to ABYV A-28 which means it is either monitored for operation or is designed to fail safe.

 

[mvweebles]

#10
As I said, it has to have been built and tested to ABYV A-28 which means it is either monitored for operation or is designed to fail safe.

While I understand your concern, for my purposes, Newmar is a decent company, and they state they are ABYC compliant. Given your stated credentials as an ABYC engineer, I would expect that when deriding a long standing marine provider, you provide more than speculation. Granted, Newmar description is a bit vague, but I would expect more from your criticism than a very general regurgitation of the ABYC standard with specifics about how Newmar fails the functional parameters. Frankly, expecting a manufacturer to submit all their bits and bobs to an independent third party testing facility is a great idea, but layers on a lot of cost and development time. I'm sure it makes sense for some things, and not for a lot of other things.

My goal in boating is not to be 100% ABYC compliant. It's very expensive risk mitigation. Better to spend time and money on substantial risks vs marginal risks. I just can't afford to eek out the last couple percentage points.

Peter

 

[CharlieJ]

Excuse me. I have said twice that to be ABYC compliant a GI must be built and tested IAW A-28. Newmar GI’s advertising does not include this designation so it appears that they do not comply. That is not vague.

 

[mvweebles]

Excuse me. I have said twice that to be ABYC compliant a GI must be built and tested IAW A-28. Newmar GI’s advertising does not include this designation so it appears that they do not comply. That is not vague.

Call me naive, but when Newmar states "engineered to conform to the latest ABYC (American Boat and Yacht Council) Standards," I take them at their word. They're a reputable company. No offense, but you're just another bloke on the internet. Some technical and functional dissection would be great, but being dissatisfied with a product description is a bit thin.

Peter

 

[twistedtree]

Call me naive, but when Newmar states "engineered to conform to the latest ABYC (American Boat and Yacht Council) Standards," I take them at their word. They're a reputable company. No offense, but you're just another bloke on the internet. Some technical and functional dissection would be great, but being dissatisfied with a product description is a bit thin.

Peter

Perhaps ask Newmar if it complies with A-28?

 

[CharlieJ]

@mvweebles #14
You asked for help and I offered factual help that you don’t apparently agree with. This bloke is done.

 

[DDW]

"engineered to conform to" is suspiciously short of "complies with and has been tested to". Why say the former if you have done the latter? It wouldn't be the first time the marketing department got ahead of the engineering dept. The older Promariner ones were complicated pieces of gear that tested themselves every few hours and had alarms if it tested open. Pretty expensive. As I noted way above, the Victron version - normally a very replable company - does not comply. They will say so if you ask.

I'd ask Newmar if you were concerned, and the main concern for me would be, will it fail a survey down the road? If it doesn't comply, there is also the remote chance that it will fail open during a fault and electrocute someone.

 

[mvweebles]

@mvweebles #14
You asked for help and I offered factual help that you don’t apparently agree with. This bloke is done.

I have reached out to Newmar and will update with their response.

In all due respect Charlie, you did not offer factual help, you offered an opinion that it "may or may not be compliant." Further that you recommend against installing it (as if there is no other benefit to a galvanic isolator). I agreed with you that their description could be more robust and asked for more detail. You offered nothing beyond repeating yourself. No alternative recommendation, no knowledge that it does not meet the requirement, no special insight except re-quoting an ABYC recommendation without even the courtesy of providing a URL citation. A lot of Fear/Uncertainty/Doubt stated as empirical/factual evidence. Honestly, just felt like someone offering problems, not solutions.

Peter

 

[Alaska Californian 37]

Call me naive, but when Newmar states "engineered to conform to the latest ABYC (American Boat and Yacht Council) Standards," I take them at their word. They're a reputable company. No offense, but you're just another bloke on the internet. Some technical and functional dissection would be great, but being dissatisfied with a product description is a bit thin.

Peter

The difference that you may not be noticing is that they only stayed it was engineered to conform to ABYC standards. That is significantly different than being tested and approved by the ABYC.

Regarding quality, I can’t speak to that however regarding legality and the potential sale of your boat at some point in the future, it does not appear acceptable.

Hopefully it works for what you’re wanting to do

 

[twistedtree]

The difference that you may not be noticing is that they only stayed it was engineered to conform to ABYC standards. That is significantly different than being tested and approved by the ABYC.

There is no such thing as "tested and approved by the ABYC". ABYC does not test, approve, or certify anything. It's all up to manufacturers to meet the specs. If they say they do, then it's just like any other specification that they claim.

 

[slowgoesit]

#10
As I said, it has to have been built and tested to ABYV A-28 which means it is either monitored for operation or is designed to fail safe.

Charlie, I appreciate your weighing in with your experience as an ABYC Master Technician, but I have to question the standard you referenced above. I could find no information on ABYV A-28 as any type of marine standard. Did you perhaps mean ABYC A-28?

 

[slowgoesit]

So the 3600w version is huge. Size of a large inverter.

Victron Energy Isolation Trans. 3600W 115/230V https://a.co/d/fImLT2p

Maybe I should rephrase my question. What do I really need? Over next 2 years, I'll probably be in a marina half the time. After that, will be in my slip where I have the only power connection. Even them, will not use it much due to large solar array that makes me net-zero.

Thoughts? Maybe a simple galvanic isolator? I'm out of my depth on this one.

Peter

Peter, our boat came to us with the Victron 3600w Isolation transformer referenced above. It is about 6 years old. The yacht club where the previous owners kept the boat gave everyone a deadline to either have their boat electrically "surveyed" to ensure proper grounding, or have an isolation transformer installed. They chose to do the later, as the cost of the "electrical survey" may have exceeded the cost of the isolation transformer. Sunchaser has the right advice that if your survey shows no problems, than you don't need the expense of the isolation transformer, just perhaps a Galvanic isolator.

Now, regarding the Victron 3600w Isolation Transformer in our boat. About two months ago, it began overheating under periods of high power draw. I trouble shot it, the 24v cooling fan was not coming on. It turned out to NOT be the fan, but rather something on the mother board that should have told the fan to come on when a certain temp was reached. Victron stated that the < six year old isolation transformer was not economically repairable, but just to buy another NEW $747.12 (plus tax and shipping) Victron Isolation Transformer . . . which anecdotally we could expect to last maybe another 6 years . . . .

Feeling disinclined to purchase another apparently faulty designed item from Victron, my solution was to remove the 24v cooling fan, and install a like sized 120v, 6 watt power draw cooling fan which runs anytime shore power is connected. If that fails, I will replace it with a NON Victron Isolation transformer. The Isolation Transformer now runs super cool! JMHO, YMMV

 

[Steve DAntonio]

While both iso xfmrs and galvanic isolators are valuable, they are not equal. An iso xfmr can completely isolate your vessel from shore, and other vessel's, grounds, and the potential adverse affects, while a galv isolator can isolate up to a point. Not every boat needs an iso xfmr, but every vessel benefits from one. At the very least, you should have an ABYC A-28 compliant (not all are) galvanic isolator. More details here https://stevedmarineconsulting.com/wp-content/uploads/2019/12/ShorePowerTransformers181-04.pdf

While there are others, DEI's galvanic isolator is fully ABYC A-28 compliant.

 

[Steve DAntonio]

For the record, because he's too modest to toot his own horn, Charlie J is an extremely knowledgeable, highly experienced, and well-respected individual in the marine electrical world, his reputation is impeccable, and he sits on the ABYC A-28 Project Technical Committee, which means he helps write the Standards for galvanic isolators. If he says it doesn't pass the sniff test, I suspect he's right, but Newmar's response would be welcomed. Typically, GIs that are fail safe, which negates the need for self-testing, prominently say "fail-safe" in their literature or on the unit. It's curious this one doesn't.

From A-28...

28.5 GENERAL REQUIREMENTS
28.5.1 Galvanic isolators shall be tested by an independent laboratory to establish compliance with this standard.
28.5.2 Galvanic isolators shall be provided with instructions covering installation requirements, including a complete set of electrical instructions with diagrams, and
28.5.2.1 operation and in-service testing requirements, and
28.5.2.2 for galvanic isolators providing studs or nuts for connection, the proper tightening torque of the stud or nut.
28.5.3 All exposed materials used in galvanic isolators and mounting hardware shall be corrosion resistant.
28.5.4 Galvanic isolators using diodes shall use a non-polarized capacitor(s), or equivalent method of meeting the requirements of A-28.12.4.
28.5.5 Galvanic isolator components shall be electrically isolated from the external housing so that galvanic isolators can be mounted directly on a conductive surface.
28.5.6 For all electrical tests, all galvanic isolator components shall be tested to the fail safe criteria found in TABLE 1.

 

[mvweebles]

For the record, because he's too modest to toot his own horn, Charlie J is an extremely knowledgeable, highly experienced, and well-respected individual in the marine electrical world, his reputation is impeccable, and he sits on the ABYC A-28 Project Technical Committee, which means he helps write the Standards for galvanic isolators. If he says it doesn't pass the sniff test, I suspect he's right, but Newmar's response would be welcomed. Typically, GIs that are fail safe, which negates the need for self-testing, prominently say "fail-safe" in their literature or on the unit. It's curious this one doesn't.



From A-28...



28.5 GENERAL REQUIREMENTS

28.5.1 Galvanic isolators shall be tested by an independent laboratory to establish compliance with this standard.

28.5.2 Galvanic isolators shall be provided with instructions covering installation requirements, including a complete set of electrical instructions with diagrams, and

28.5.2.1 operation and in-service testing requirements, and

28.5.2.2 for galvanic isolators providing studs or nuts for connection, the proper tightening torque of the stud or nut.

28.5.3 All exposed materials used in galvanic isolators and mounting hardware shall be corrosion resistant.

28.5.4 Galvanic isolators using diodes shall use a non-polarized capacitor(s), or equivalent method of meeting the requirements of A-28.12.4.

28.5.5 Galvanic isolator components shall be electrically isolated from the external housing so that galvanic isolators can be mounted directly on a conductive surface.

28.5.6 For all electrical tests, all galvanic isolator components shall be tested to the fail safe criteria found in TABLE 1.

Thanks Steve. And thans Charlie for the insight. I have a query out to Newmar with a specific question about A-28.

Peter

 

[Alaska Californian 37]

There is no such thing as "tested and approved by the ABYC". ABYC does not test, approve, or certify anything. It's all up to manufacturers to meet the specs. If they say they do, then it's just like any other specification that they claim.

Self-certification by the Manufacturer does NOT mean anything. Perhaps my wording could have been clearer; the Manufacturer is responsible to provide ABYC documentation from a 3rd Party testing facility certifying their product complies and once that is accepted, the product is approved. The Manufacturers word means nothing for a reason.

Of course, if he doesn’t want to listen to a guy that actually helps write the rules for them, I guess my two cents don’t really matter either so good luck.

 

[twistedtree]

Perhaps my wording could have been clearer; the Manufacturer is responsible to provide ABYC documentation from a 3rd Party testing facility certifying their product complies and once that is accepted, the product is approved. The Manufacturers word means nothing for a reason.

I'm pretty sure ABYC doesn't do this either. I don't believe they evaluate products, or test results, or in anyway evaluate or "approve" anything.


What you have is indeed just the manufacturer's word, just as you have their word about most every aspect of the product.

 

[mvweebles]

Of course, if he doesn’t want to listen to a guy that actually helps write the rules for them, I guess my two cents don’t really matter either so good luck.

I'm sorry I came across that way. Urging compliance with ABYC is a great idea. Instead of saying Newmar (or any other manufacturer) does/does not comply, a murky response of dissatisfaction with the marketing representation and therefore its not recommended was a bit frustrating. I am not seeking to become an expert in galvanic isolators or ABYC requirements, just buy a piece of kit and move on to the next project.

At the end of Steve Ds article linked above, he offers a "resource section." Listed are three galvanic isolators - DEI (new brand name to me), Promariner, and Newmar. Does that mean that all three comply with A-28 as he strongly recommends in the article? Or does that mean they are simply suppliers (e.g. "resources") and its up to the reader to (a) digest the material in the article, and (b) reach out to each manufacturer to validate compliance which I am in the process of doing for Newmar? In his post in this thread, he states DEI (among others) is ABYC compliant. Am I to infer that Newmar is not as that was the specific brand in question?

I realize I'm going to step on some toes, and sound a bit ungrateful for the deep subject matter expertise folks like Steve D (and Charlie, with whom I was unfamiliar) share with the boating community via forums like this (i am truly thankful). But sometimes it just feels like a simple question can be answered with a simple answer. Instead, "What time is it?" gets a response of "here's how you build a clock."

Peter

EDIT - here is a link for DEI, now rebranded as Dairyland. Even for their basic 30A galvanic isolator, you need to submit a request for a quote. There is no pricing or availability information. Of interest to many, they apparently make GIs for dual power inlets such as 2x30A (amongst other more advanced power inlet configurations).

https://www.dairyland.com/request-a-quote/

 

[Iggy]

I'm pretty sure ABYC doesn't do this either. I don't believe they evaluate products, or test results, or in anyway evaluate or "approve" anything.


What you have is indeed just the manufacturer's word, just as you have their word about most every aspect of the product.

I must say, this topic is confusing. I can see why some members are not trying to be rude but trying as I am to understand the ABYC standards.

I maybe off base. but if something was UL approved or labeled UL. You know that they had it in there hands and tested by them.

I am sure TT is right, I am not in his league. But some testing must be done, how can a compony say its product is meets ABYC standards on its own?

 

[mvweebles]

I must say, this topic is confusing. I can see why some members are not trying to be rude but trying as I am to understand the ABYC standards.

I maybe off base. but if something was UL approved or labeled UL. You know that they had it in there hands and tested by them.

I am sure TT is right, I am not in his league. But some testing must be done, how can a compony say its product is meets ABYC standards on its own?

The Dairyland GI I linked above gives detailed information. Even names the lab that did the testing not just to ABYC, but an ISO requirement too. Even discusses number of cycles though i dont know what that means but sounds pretty transparent. They give everything except price and availability.

I guess I don't understand the absolute emphasis on testing. Can a knowledgeable person not look at a circuit diagram and tell whether it will/will-not fail safe? Frankly, I'd be okay with a reputable company who complies with a standard but does not seek outside test validation - this happens all the time. Sure, you're relying on the company to be honest which is why I qualify it with "reputable company." Heck, to TTs point, even with Dairylands lofty representations, you're relying on them to have accurately portrayed them. I recently checked to validate a company's claimed A-Rating from the Better Busines Bureau which was proudly showcased on their homepage. Guess what? In actuality, they had a lousy BBB rating (company was Renogy).

This is the one and only Galvanic Isolator I will likely purchase in my lifetime. I didn't realize I needed to dissect them. Was hoping for a specific recommendation as indicated in the title of the thread.

Peter