Electrical

[markalexander]

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Source of the post The plug that looks like a "regular 3 prong plug" is actually a 240V 20A plug. If you look at the prongs, they are actually perpendicular to how a "regular 3 prong plug" is. They are both "horizontal" whereas a 120VAC plug they are both "vertical".

However, the wiring is the same, it would be:
plug - 50 amp socket
green - green
white - black X
black - red Y

There is no neutral going INTO the boat's isolation transformer. On the OUTPUT side of the boat's isolation transformer there is a neutral that goes to your main electrical panel. Then you can have 120CVAC from either hot to that neutral, or 240VAC across the two hots (just like a normal house).

Hi km1125
That's excellent description and instructions. I missed that the plug was a 20amp
The neutral makes sense due to the Isolation Transformer
I'll put it all together in the next few days and test it out. I'll report back if it works
Thanks again for giving your time to answer my questions and everyone else's questions too!
Mark

Actually, I misspoke... it was a 15A 240V plug that I used. The twenty amp versions (both 125 and 250v) have prongs perpendicular to each other, but opposite in configuration so they can't be plugged into the wrong socket. For the 15A 250 both prongs are perpendicular to the prongs on a 15A 125V plug.

Hi km1125

I'm glad you clarified and that image you show summarizes some of the options nicely. I spent a few hours last night trying to find a 20amp with horizontal prongs.

While researching 20amp 250 volt male plugs I saw all of the different configurations with the T plugs and others for different amperages etc, as you show in your image. It appears the 20amp T-plug (NEMA 6-20R as shown in your image) will also work on the step up converter 240v outlet. If this is the case and this all works, then this is likely the type of male plug that I will purchase and hook up with a 12/3 short cable to the 50amp female with my 5000 watt converter.

For now, I used a heavier duty 14/3 wire (see attached) and wired to the 50AMP 125/250V NEMA SS2-50R and will give it a try on the boat tomorrow.

ALSO: After doing all this research I came across a 30A Male Shore power to Marine 50A SS2-50R Female where the two hots bridged - seems exactly what I require at the dock sometimes! https://www.amazon.ca/gp/product/B01KF359K2/ref=ewc_pr_img_1?smid=A2565OKC78981M&psc=1
If the configuration that you setup with the 250v converter was successful and the one I set up last night works on our boat, then this adapter should work too. All we are doing is supplying two hot wires of lower amperage to the 50amp plug (two hots bridge mode) This would solve our other issue of visiting a few yacht clubs on Lake Ontario that only have a single 30amp available for each slip. This is a very exciting possibility that I'll try next after testing the 5000Watt step up converter.

Stay tuned!

Thanks again for all your assistance with this
Mark

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[km1125]

If I'm understanding your note correctly, then the "30A Male Shore power to Marine 50A SS2-50R Female where the two hots bridged" will NOT work with an isolation transformer, as the two "hots" would be in phase and the voltage between them would be ZERO. So, no power to power the isolation transformer. If there was not an isolation transformer, then that cable would work on a boat with a 250V plug, but only for 125V appliances. None of the 250 volt stuff would work at all.

[markalexander]

Source of the post If I'm understanding your note correctly, then the "30A Male Shore power to Marine 50A SS2-50R Female where the two hots bridged" will NOT work with an isolation transformer, as the two "hots" would be in phase and the voltage between them would be ZERO. So, no power to power the isolation transformer. If there was not an isolation transformer, then that cable would work on a boat with a 250V plug, but only for 125V appliances. None of the 250 volt stuff would work at all.

Oh, I guess I needed to understand the word "bridged". Seems like bridged is taking same line and using it for the two hot lines (X and Y) on the 50 amp, so, as you say, if they are same phase it won't work. That's the whole point of the 2x30amp to 50amp "Smart Y" and why it won't won't at some Yacht Clubs we went to because I could not find two 30amp that were out of phase.
I'm learning a great deal about this from you and appreciate your input.
Maybe I'll have to live with the 120 to 240volt Converter when I can't get power at the dock through 2x30amp and there is no 50amp either.
Thanks again!
Mark

[markalexander]

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Source of the post

Hi km1125
That's excellent description and instructions. I missed that the plug was a 20amp
The neutral makes sense due to the Isolation Transformer
I'll put it all together in the next few days and test it out. I'll report back if it works
Thanks again for giving your time to answer my questions and everyone else's questions too!
Mark

Actually, I misspoke... it was a 15A 240V plug that I used. The twenty amp versions (both 125 and 250v) have prongs perpendicular to each other, but opposite in configuration so they can't be plugged into the wrong socket. For the 15A 250 both prongs are perpendicular to the prongs on a 15A 125V plug.

Hi km1125

I'm glad you clarified and that image you show summarizes some of the options nicely. I spent a few hours last night trying to find a 20amp with horizontal prongs.

While researching 20amp 250 volt male plugs I saw all of the different configurations with the T plugs and others for different amperages etc, as you show in your image. It appears the 20amp T-plug (NEMA 6-20R as shown in your image) will also work on the step up converter 240v outlet. If this is the case and this all works, then this is likely the type of male plug that I will purchase and hook up with a 12/3 short cable to the 50amp female with my 5000 watt converter.

For now, I used a heavier duty 14/3 wire (see attached) and wired to the 50AMP 125/250V NEMA SS2-50R and will give it a try on the boat tomorrow.
...

Stay tuned!

Thanks again for all your assistance with this
Mark

Good morning km1125

The 5000Watt voltage step up Transformer that supplies 240volt with no neutral produces power on our boat, hallelujah!! I can't thank you enough for your instructions and assistance to get this up and running.

It's less than 12amps but that will be enough power for some battery charging over the winter and running some low amp power tools or making a coffee on the boat in the spring.

Now I have to figure out how I can wire up a single 30amp shore power outlet to power at least the house side (Line #1) on our boat. I suspect if I tap into, for example, the 30amp from the generator to only the Line 1 side of the boat (via a separate selector switch and additional selector switch) then I can get 30 amp to Line #1 side of the boat.

I also suspect, if I wanted to get real fancy I could have a second 30amp inlet from shore power tapped into Line 2 via the other side of the generator to run the air conditioning system side of our boat.

I don't know if this would all meet ABYC standards unless, at minimum I had separate breakers for each 30amp into the boat. I'm not sure what else would be required to meet standards. This setup would bypass the isolation transformer and allow for galvanic corrosion but it would only be for 1 or 2 days a few times per year.

Regardless, thanks again for all your help and I'll repost here once I figure out the next step so others may benefit.
Have a great day!
Mark

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[km1125]

Source of the post
...
Now I have to figure out how I can wire up a single 30amp shore power outlet to power at least the house side (Line #1) on our boat. I suspect if I tap into, for example, the 30amp from the generator to only the Line 1 side of the boat (via a separate selector switch and additional selector switch) then I can get 30 amp to Line #1 side of the boat.

I also suspect, if I wanted to get real fancy I could have a second 30amp inlet from shore power tapped into Line 2 via the other side of the generator to run the air conditioning system side of our boat.

I don't know if this would all meet ABYC standards unless, at minimum I had separate breakers for each 30amp into the boat. I'm not sure what else would be required to meet standards. This setup would bypass the isolation transformer and allow for galvanic corrosion but it would only be for 1 or 2 days a few times per year. ....

I haven't thought through everything in this part of the post, but one thing you NEED to consider if going this route is how you're going to handle the neutral/ground bond.

When you're on shore power directly (with no isolation transformer) you rely on the neutral/ground bond in the shore electrical panel. There is no such bond on the boat. Until you have a generator or inverter setup, then those setups have to be able to switch in a neutral/ground bond when either of those is suppling power, and disable it when they're not.

When you have an isolation transformer there's a neutral/ground bond established on the output side of the isolation transformer. If you just "tap in" at this point to connect a shore power connection, you're not necessarily disabling this neutral/ground bond and that could cause issues.

[bud37]

Source of the post
I don't know if this would all meet ABYC standards unless, at minimum I had separate breakers for each 30amp into the boat. I'm not sure what else would be required to meet standards. This setup would bypass the isolation transformer and allow for galvanic corrosion but it would only be for 1 or 2 days a few times per year.

At this point I just want to add something to consider. Whatever you do in that direction may not only affect your boat but all the ones around your boat, corrosion wise, and with a bad appliance could be harmful to someone falling in the water given the right conditions.

On the other hand they can be affecting yours, testing your boat and surroundings may not be a bad idea considering where you are. Are you in the water for the winter ? I know another subject but may be related considering.

[markalexander]

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Source of the post
...
Now I have to figure out how I can wire up a single 30amp shore power outlet to power at least the house side (Line #1) on our boat. I suspect if I tap into, for example, the 30amp from the generator to only the Line 1 side of the boat (via a separate selector switch and additional selector switch) then I can get 30 amp to Line #1 side of the boat.

I also suspect, if I wanted to get real fancy I could have a second 30amp inlet from shore power tapped into Line 2 via the other side of the generator to run the air conditioning system side of our boat.

I don't know if this would all meet ABYC standards unless, at minimum I had separate breakers for each 30amp into the boat. I'm not sure what else would be required to meet standards. This setup would bypass the isolation transformer and allow for galvanic corrosion but it would only be for 1 or 2 days a few times per year. ....

I haven't thought through everything in this part of the post, but one thing you NEED to consider if going this route is how you're going to handle the neutral/ground bond.

When you're on shore power directly (with no isolation transformer) you rely on the neutral/ground bond in the shore electrical panel. There is no such bond on the boat. Until you have a generator or inverter setup, then those setups have to be able to switch in a neutral/ground bond when either of those is suppling power, and disable it when they're not.

When you have an isolation transformer there's a neutral/ground bond established on the output side of the isolation transformer. If you just "tap in" at this point to connect a shore power connection, you're not necessarily disabling this neutral/ground bond and that could cause issues.

Hi km1135
Yes, I agree with you that there are 'other' considerations with adding an additional (or two) 30amp shore power connection(s) to the boat, especially if I bypass the isolation transformer.

After reading your post and bud37's post today I did a lot more reading and research this afternoon and I have decided to hire a marine electrician to look at the feasibility and options available to me with our current boat configuration. There are too many potential side effects that could negatively (no pun intended) effect the electrical systems on the boat and more importantly in the water.

Again, I'll keep you posted on this in the event that it helps someone else who has a similar configuration to our boat.

Thank you again
Mark

[markalexander]

Source of the post

Source of the post
I don't know if this would all meet ABYC standards unless, at minimum I had separate breakers for each 30amp into the boat. I'm not sure what else would be required to meet standards. This setup would bypass the isolation transformer and allow for galvanic corrosion but it would only be for 1 or 2 days a few times per year.

At this point I just want to add something to consider. Whatever you do in that direction may not only affect your boat but all the ones around your boat, corrosion wise, and with a bad appliance could be harmful to someone falling in the water given the right conditions.

On the other hand they can be affecting yours, testing your boat and surroundings may not be a bad idea considering where you are. Are you in the water for the winter ? I know another subject but may be related considering.

Hi bud37

Thanks for your comments. We are not in the water for the winter, not back in until early/mid April 2025 lol

As I said to km1125 I have decided to hire a marine electrician to look at the feasibility and options available to me with our current boat configuration. There are too many potential negative (no pun intended) consequences that could effect the electrical systems on our boat and worse, the people and boats in the water around me.

Thank you again for your comments.
Mark