Isolation transformers

Has anyone had any experience with this brand??

Looking at the output side in there diagram. They leave the ground disconnected. So I emailed them saying that white and ground should be connected if if the black/hot wire when to ground than the breaker would not trip.

In their response, "Yes. Connect White output lead to boat ground." Plus no galvanic isolator would be needed. From what I have been reading, one would be needed. Any thoughts?

https://www.bridgeportmagnetics.com/bmg-product/marine-isolation-transformers/

There are usually two grounds on marine isolation transformers (220V). One is for the primary winding wires going to shore power. Two split phases used only on primary, no neutral.

The other ground separates the primary winding from the secondary winding and needs to be connected to the secondary neutral wire (usually a center tap in the secondary wire). The primary and secondary grounds do not get connected. No galvanic isolator should be used.

For a 120V isolation transformer, there would be only one ground and it gets connected to secondary winding neutral. Again. no galvanic isolator should be used.

With isolation transformers, stray currents will return to the secondary winding not to the shore pedestal. That is the whole point of an isolation transformer.

Iggy said:

Has anyone had any experience with this brand??

Looking at the output side in there diagram. They leave the ground disconnected. So I emailed them saying that white and ground should be connected if if the black/hot wire when to ground than the breaker would not trip.

In their response, "Yes. Connect White output lead to boat ground." Plus no galvanic isolator would be needed. From what I have been reading, one would be needed. Any thoughts?

https://www.bridgeportmagnetics.com/bmg-product/marine-isolation-transformers/

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I believe you have miss interpreted their schematic. The ground being not used and capped off is internal to the puck. Look past the dashed circle and you will see the Black, White, and Green wires that you will be working with.

What intrigues me most about this system is a 50A 125/240v system only weighs 150 lbs. this is 100 lbs. less than any other system I have reviewed. I am seriously considering this system. I'm just looking for some feed back from some one who is currently using it.

tiltrider1 said:

I believe you have miss interpreted their schematic. The ground being not used and capped off is internal to the puck. Look past the dashed circle and you will see the Black, White, and Green wires that you will be working with.

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From the shore cord, yes the ground is capped off/not used. Yes, I see the wires after the dashed circle. But not sure what you are driving at?

Now they e-mailed me back stating to connect the white and green on the output side. I did quote them, maybe I am not understanding them?

The other reason why I am thinking of instilling these is. My galvanic isolators are 20 years old, so they don't meet ABYC standards anymore.

Iggy said:

From the shore cord, yes the ground is capped off/not used. Yes, I see the wires after the dashed circle. But not sure what you are driving at?

Now they e-mailed me back stating to connect the white and green on the output side. I did quote them, maybe I am not understanding them?

The other reason why I am thinking of instilling these is. My galvanic isolators are 20 years old, so they don't meet ABYC standards anymore.

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What problem are you trying to solve? A new, compliant Promariner 60-amp galvanic isolator costs about $300. I took a look at Bridgeport Magnetics website, quite interesting but no indication of what their solutions cost versus an isolator.

i have a bridgeport magnetics mp3.6 on my steel boat. i don't think that their system exactly meets the requirements for aybc certification for marine installations. i don't know if i'd bought a different one after i investigated more thoroughly, but i may have. i got the one i have from an ebay listing.
when i bought the pair of transformers i needed for my new to me boat i got the victron energy units.
i think bridgeport meets the european standard, i thought i read that they thought it was a better method than the usa standard.
bridgeport units are certainly smaller, that's for sure. works fine, no heat from it, it does buzz a little. i am going to add some rubber isolators to hopefully reduce that some. i mounted it in the forward berth area so it was within the wire length requirement to the shore inlet/distribution panel. the buzz is a little annoying in the bunk if there's no other white noise.
their installation says to leave the ground from the shore cord terminated at the shore inlet, don't bring it to the transformer. you create the ground/neutral connection for the boats distribution in the wiring cavity. i can't remember if there was an accessible shield connection or not, but i don't think so. the case is all plastic too so a case ground does nothing.

On the back side of your shore power socket you will have an output for green, white and black. You won’t use the green. You connect the white and black to the puck. The puck outputs red&black these connect to the boats L1, white & yellow these connect to the boats neutral and ground, . At this point your boat is properly grounded and you are not connected to shore ground. This prevents any stray DC from entering your boat via the ground wire.

tiltrider1 said:

On the back side of your shore power socket you will have an output for green, white and black. You won’t use the green. You connect the white and black to the puck. The puck outputs red&black these connect to the boats L1, white & yellow these connect to the boats neutral and ground, . At this point your boat is properly grounded and you are not connected to shore ground. This prevents any stray DC from entering your boat via the ground wire.

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that's exactly how it hooks up. i think you can decide whether or not to hook the ground to neutral at the puck, or at the distribution panel. either way it does the same thing, and you have isolation.

tiltrider1 said:

What intrigues me most about this system is a 50A 125/240v system only weighs 150 lbs. this is 100 lbs. less than any other system I have reviewed. I am seriously considering this system. I'm just looking for some feed back from some one who is currently using it.

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like i mentioned, i'm using the 3.6 version. is there something specific you need to know about it?

Bmarler I was trying to answer Iggy’s question about wiring.

My question to you is does it work as advertised? Losing a 100 lbs. is significant, I need a 50a 125/250v unit. I can locate the unit in the engine room so a bit of buzzing is probably tolerable.

Regarding grounding with isolation transformers

The thing you do NOT want to do is to create a ground path from your boat to your shore power cord. That is exactly what you are trying to prevent.

On my Charles Industries Isolation Transformers the metal case of the transformer is connected to shore power ground, but that case is not connected to anything in the isolation transformer, it is just the case. If these transformers use a plastic case then no ground connection would be needed.

My only challenge with these or any isolation transformer is hanging them on a vertical surface. You would want that surface to be really strong because boats move and you need to consider the loading forces.

tiltrider1 said:

On the back side of your shore power socket you will have an output for green, white and black. You won’t use the green. You connect the white and black to the puck. The puck outputs red&black these connect to the boats L1, white & yellow these connect to the boats neutral and ground, . At this point your boat is properly grounded and you are not connected to shore ground. This prevents any stray DC from entering your boat via the ground wire.

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I am not seeing the White and ground connected! As I have been mentioning.

They are advertising, UL Marine listed. Is that as good as ABCY, not sure?

tiltrider1 said:

Bmarler I was trying to answer Iggy’s question about wiring.

My question to you is does it work as advertised? Losing a 100 lbs. is significant, I need a 50a 125/250v unit. I can locate the unit in the engine room so a bit of buzzing is probably tolerable.

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got it, sorry for the confusion.
to answer your question, yes, it works perfectly. it makes all the power my shore breaker will allow with no voltage drop. it's about the simplest isolation transformer you could get, and the small size is bonus too.

ksanders said:

Regarding grounding with isolation transformers

The thing you do NOT want to do is to create a ground path from your boat to your shore power cord. That is exactly what you are trying to prevent.

On my Charles Industries Isolation Transformers the metal case of the transformer is connected to shore power ground, but that case is not connected to anything in the isolation transformer, it is just the case. If these transformers use a plastic case then no ground connection would be needed.

My only challenge with these or any isolation transformer is hanging them on a vertical surface. You would want that surface to be really strong because boats move and you need to consider the loading forces.

Click to expand...

Kevin, I am so disappointed in you today. I see no reason why the Puck can not be mounted in a Horizontal surface. For me the biggest challenge is the input wires come out of the back of the Puck and the output wires come out of the side. This mean I need to mount it with a spacer so that it is not flush to a surface. Maybe you need to do this anyway for air circulation.

Iggy said:

I am not seeing the White and ground connected! As I have been mentioning.

They are advertising, UL Marine listed. Is that as good as ABCY, not sure?

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you make the neutral/ground connection yourself. i did it at the back of the transformer as it's now the new power source, but an argument could be made for doing it at the distribution panel.
i think the only thing that disqualifies it as abyc compliant is the lack of a metal case, and possibly the lack of an accessible faraday wire.
the ul marine cert and the european cert is good enough for me. the surveyor i talked to about it was perfectly fine with it too. i think the plastic case is a good thing, nothing to rust or short out on.
they recommend hooking a small light bulb on the input to help reduce nuisance tripping when you first energize it but i don't have any issue with that.

Iggy,

I'm not sure where the confusion is. Possibly I'm not understanding your thought process. The schematic shows the puck's white & yellow wire being connected to the Boats neutral and ground wires. I'll admit they are a little sloppy in showing the connection in the schematic but it is there none the less.

If I was doing this I would wire the puck's white & yellow straight to a bus and bring the boats neutral(white) and ground(green) to this same bus. I should rephrase that a bit. I would run the wires coming from the puck to a double pole breaker and then to the appropriate buses.

ksanders said:

Regarding grounding with isolation transformers

The thing you do NOT want to do is to create a ground path from your boat to your shore power cord. That is exactly what you are trying to prevent.

On my Charles Industries Isolation Transformers the metal case of the transformer is connected to shore power ground, but that case is not connected to anything in the isolation transformer, it is just the case. If these transformers use a plastic case then no ground connection would be needed.

My only challenge with these or any isolation transformer is hanging them on a vertical surface. You would want that surface to be really strong because boats move and you need to consider the loading forces.

Click to expand...

i thought abyc required the shield wire to be connected to the shore ground, and the case connected to boat ground.
the victron ones i just bought provide terminals for all of the connections, i haven't seen the charles industries ones.

i should add, in regards to these puck transformers from bridgeport. there are marine electricians that do not recommend them for installation as an isolation transformer due to the lack of an accessible shield wire to connect the shore side safety ground to.
these pucks almost qualify as polarization transformers but they don't have a metal case.
i have read plenty of opinions and reasons for the abyc and the european standards and how they differ, and in the end i decided i could live with any potential risk in my particular installation.
do your own research though before you purchase.

Thanks for all the feed back! I am looking at the MP3.6
using https://www.bridgeportmagnetics.com/wp-content/uploads/2020/12/Marine-Puck-Sales-sheet.pdf

Maybe am nuts! I am not seeing ground wire connected to the white wire. Now Kevin said that "you make the neutral/ground connection yourself." Which is great in it self. It should be connected.

For the person that does not know any better, the PDF is wrong.

Iggy said:

Thanks for all the feed back! I am looking at the MP3.6
using https://www.bridgeportmagnetics.com/wp-content/uploads/2020/12/Marine-Puck-Sales-sheet.pdf

Maybe am nuts! I am not seeing ground wire connected to the white wire. Now Kevin said that "you make the neutral/ground connection yourself." Which is great in it self. It should be connected.

For the person that does not know any better, the PDF is wrong.

Click to expand...

the pdf shows a floating (no grounded power conductor) example. i have read arguments that this is a better way. apparently there are commercial boats that have adopted that system using double pole breakers for each branch and leaving the safety ground wire unconnected to any other conductor. abyc doesn't endorse that method, and any surveyor will raise an eyebrow when they put their little tester in your outlets.
i have a different document from bridgeport magnetics somewhere. it shows the option to tie the neutral to ground. don't see it on the website any more.
and for what it's worth, regarding mounting positions, all of the wires can come out the side. you don't need to come out the back.

Bmarler said:

the pdf shows a floating (no grounded power conductor) example. i have read arguments that this is a better way. apparently there are commercial boats that have adopted that system using double pole breakers for each branch and leaving the safety ground wire unconnected to any other conductor. abyc doesn't endorse that method, and any surveyor will raise an eyebrow when they put their little tester in your outlets.
i have a different document from bridgeport magnetics somewhere. it shows the option to tie the neutral to ground. don't see it on the website any more.
and for what it's worth, regarding mounting positions, all of the wires can come out the side. you don't need to come out the back.

Click to expand...

Ok, it's not me. I could not find it. But, I would connect ground and neutral. Lets face it, why is this done in our homes. If the Hot wire became loose and and touched the outside cabinet of a device it would become hot too.

Case in point on my boat, the hot water heater, microwave, clothes washing machine and there maybe more. Now boat wiring is almost a art in it self, so I maybe missing a few things.

Iggy said:

Ok, it's not me. I could not find it. But, I would connect ground and neutral. Lets face it, why is this done in our homes. If the Hot wire became loose and and touched the outside cabinet of a device it would become hot too.

Case in point on my boat, the hot water heater, microwave, clothes washing machine and there maybe more. Now boat wiring is almost a art in it self, so I maybe missing a few things.

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completely agree. i tied my neutral to ground and would recommend it for anyone doing a similar installation.

I just received this!!

Safety Standards - Marine-Puck Shore Power Isolation Transformers.
Bridgeport Magnetics Group’s Marine-Puck™ ULMARINE certified boat isolation transformers emulate Iso-Puck™ IEC/UL 60-601 certified medical isolation transformers. The resin enclosures cannot corrode and do not require grounding, and transformers can be mounted onto any surface on board without reference to shore- or boat-ground. Currently their contemporary construction and choice of materials does not comply with the specifications set down in the advisory ABYC standard, but recently a ABYC subcommittee was formed and tasked with amending and modernizing the E-11 section dealing with shore power issues to include toroidal transformers in non- metallic enclosures. The subcommittee has now formulated a set of changes which will be presented and hopefully accepted by the membership during ABYC Standards week in January 2022.

tiltrider1 said:

Kevin, I am so disappointed in you today. I see no reason why the Puck can not be mounted in a Horizontal surface. For me the biggest challenge is the input wires come out of the back of the Puck and the output wires come out of the side. This mean I need to mount it with a spacer so that it is not flush to a surface. Maybe you need to do this anyway for air circulation.

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LOL!!!

Yes, of course you could mount it on a horizontal surface. My apologies for not clairifing.

When I mounted my Charles Industries (now out of production) transformers they also showed vertical mounting, which I chose not to do.

Iggy said:

I just received this!!

Safety Standards - Marine-Puck Shore Power Isolation Transformers.
Bridgeport Magnetics Group’s Marine-Puck™ ULMARINE certified boat isolation transformers emulate Iso-Puck™ IEC/UL 60-601 certified medical isolation transformers. The resin enclosures cannot corrode and do not require grounding, and transformers can be mounted onto any surface on board without reference to shore- or boat-ground. Currently their contemporary construction and choice of materials does not comply with the specifications set down in the advisory ABYC standard, but recently a ABYC subcommittee was formed and tasked with amending and modernizing the E-11 section dealing with shore power issues to include toroidal transformers in non- metallic enclosures. The subcommittee has now formulated a set of changes which will be presented and hopefully accepted by the membership during ABYC Standards week in January 2022.

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interesting to say the least, and very timely as it relates to our discussion. i will be most interested to see what recommendations they come up with in regards to the wiring of these.
i read a very contentious series of arguments from a couple of very experienced marine electricians regarding the use of toriodial transformers and whether or not to tie one of the current carrying conductors to ground. one of these people was working with the abyc on the matter. very interesting reading as i'm doing isolation transformers right now myself.

Iggy, I just figured out why we could not communicate. We were looking at two different schematics. You were looking at the one in the brochure and I was looking at the one on the web under Electrical Schematics. The brochure only shows a partial schematic while the web shows the complete schematic.

So everyone is right. There is a partial schematic that is miss leading and there is a schematic that show grounds and neutrals being combined.

Interesting. No need to have more than two wires in shore cables. If one of two is open, no power to boat. Mind you the ground ending at boat protects someone cutting the cable.

what about power going into the water through the recommended bonding system?

Soo-Valley said:

Interesting. No need to have more than two wires in shore cables. If one of two is open, no power to boat. Mind you the ground ending at boat protects someone cutting the cable.

what about power going into the water through the recommended bonding system?

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There is no where for any current to go, since the boat is isolated from shore power.

ksanders said:

There is no where for any current to go, since the boat is isolated from shore power.

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I see, Isolated it originates inside boat by induction so stray current will look for source and thus not have anywhere to go.