2003 396 ShorePower

[bud37]

Ok, so I am no expert at this stuff and am not saying anything is wrong with this plan , but thinking about this has given me pause for some concern......I have been wrong before many times.... ...#1 would be phasing. #2, I believe but not sure that you would have to install breakers at the inlet point.....#3 would be if the galvanic isolators would still function because you have a shared neutral and ground on the boat.....remember all the adaptors cords we use are exterior to the boat breakers.
A consult with a marine electrician may be wise here, although I have to admit it seems easy enough.....good luck man and take your time.

[buster53]

I’ll pass this on FWIW…
I used to have a 3807 wired the same way, 120V-50 amp. Since that power is basically non existent, the previous owner had special power cords made, 30 amp male and 50 amp female ends. Worked great. I might add that we also had 3 AC units and they pulled 29 amps. Cords got warm but never dangerously so. In 7 years, we never had a problem.

[650Guy]

I will admit, this concept is pushing my electrical knowledge to the limits for sure!

I found a string on a Cruisers form that someone was trying to do the same thing I am. It seems pretty possible, so far the last questions I have in my mind are:

1) Do I need a new breaker at the point of connection or will the twin 50amp breakers still work? Someone mentioned using a new triple pole breaker? not sure how that would work as I only would be feeding it 2 hot lines.

2) Do I need to mess with my galvonic isolators? I don't think so, as long as I tie my neutrals after the breaker boat side.

If I do this little, but very expensive job, it will simplify my shore power life significantly! Lets face it, 50A/125v lines just don't exist anymore leaving me to do what I am currently doing, which is using pigtails and running reduced amperage lines. All of which seem to be a risk.

[650Guy]

So I think this is my wiring plan! I'm probably going to run this past my local marina mechanic to make sure I'm not missing anything, and by all means take anyones input as this community has always served me well.

[Midnightsun]

Your boat is already set up with dual 50a breakers on shore power 1 and 2 so the wiring is more than adequate as you are going to be supplying the same amount of voltage and amps with a 125/250 50a setup.

Not sure what the spec is however after x feet from inlet to panel an additional breaker is required. Since your boat is already receiving the same juice and there is no breaker near the inlet, one must assume Carver did this correctly (to standards) so no further breakers should be required.

There was mention of issues combining 2 neutrals. No different than all the boats using a Y splitter into the boat, both neutrals and grounds are obviously combined and lord knows how many use Y splitters.

Good idea to run this by your mechanic, I am no electrician by trade however I have been wiring industrial motors and the such for over 40 years mostly dealing with 600v 3 phase and have done quite a bit of household wiring. That being said, there may be some nuances that are really specific to boats that I am not familiar with.

The cord required to run 50a 125/250 is a huge and heavy pig. So much so I decided to make my own, slimed down lighter version or a weight watchers version if you prefer. . The key to this is obviously the jacket that needs to be robust and weather proof and the copper stranded wires need to be minimum 6 gauge which is what is found in the standard marine 50a cord. Here is a link to my build. viewtopic.php?f=3&t=3988&hilit=diy+shore+power+cord

[km1125]

The one problem with your drawing above Is that the neutrals go to the junction box and then it appears to go to "distribution" just like the ground. On a boat, the neutrals should ALSO be switched by the main breaker. This is why someone mentioned that you might consider a "three pole" breaker. That would accommodate both hots AND the neutral. Your existing breakers should handle this just fine, they will just switch the neutrals separately. So, each hot and one of the neutrals goes to each of your existing breakers.

[Midnightsun]

QR_BBPOST The one problem with your drawing above Is that the neutrals go to the junction box and then it appears to go to "distribution" just like the ground. On a boat, the neutrals should ALSO be switched by the main breaker. This is why someone mentioned that you might consider a "three pole" breaker. That would accommodate both hots AND the neutral. Your existing breakers should handle this just fine, they will just switch the neutrals separately. So, each hot and one of the neutrals goes to each of your existing breakers.

I believe the neutrals go to the existing 50a breakers on both shore power 1 and 2 and are therefor both are switched. If they were not switched before, why would they need to be now? Same power and amperage is going to the same place through the same wires

[km1125]

QR_BBPOST
I believe the neutrals go to the existing 50a breakers on both shore power 1 and 2 and are therefor both are switched. If they were not switched before, why would they need to be now? Same power and amperage is going to the same place through the same wires

If the boat was built in 2003 (or anytime since the early 90's) then the neutrals should be "switched" or protected by the main breakers. However, I have no idea what a previous owner might have done. If the OP finds that the neutrals are NOT 'switched', then he needs to correct that SAFETY violation. It would become evident when you plugged into a pedestal that had 'hot' and 'neutral' incorrectly wired.

If I was doing this kind of work to a boat built in 1950 that only had a single-pole breaker(and only 'switching' hot), I would certainly upgrade that situation.

[650Guy]

QR_BBPOST Your boat is already set up with dual 50a breakers on shore power 1 and 2 so the wiring is more than adequate as you are going to be supplying the same amount of voltage and amps with a 125/250 50a setup.

Not sure what the spec is however after x feet from inlet to panel an additional breaker is required. Since your boat is already receiving the same juice and there is no breaker near the inlet, one must assume Carver did this correctly (to standards) so no further breakers should be required.

There was mention of issues combining 2 neutrals. No different than all the boats using a Y splitter into the boat, both neutrals and grounds are obviously combined and lord knows how many use Y splitters.

Good idea to run this by your mechanic, I am no electrician by trade however I have been wiring industrial motors and the such for over 40 years mostly dealing with 600v 3 phase and have done quite a bit of household wiring. That being said, there may be some nuances that are really specific to boats that I am not familiar with.

The cord required to run 50a 125/250 is a huge and heavy pig. So much so I decided to make my own, slimed down lighter version or a weight watchers version if you prefer. . The key to this is obviously the jacket that needs to be robust and weather proof and the copper stranded wires need to be minimum 6 gauge which is what is found in the standard marine 50a cord. Here is a link to my build. viewtopic.php?f=3&t=3988&hilit=diy+shore+power+cord

Couple clarifications on my extremely professional electrical wiring diagram. I honestly didn't realize the white's (neutrals) were switched at the breaker as I have not opened it up yet (and I'm TOTALLY not a professional electrician, nor did I stay at a holiday inn express). I simply know enough to get by and not kill myself. Hopefully! I had envisioned in my tiny mind it was just like a house box where your neutrals went to a bus bar along the side and the breakers simply had the hot in/out, so that was my bad!

Now that I look at the manufacturers diagram I clearly see the white coming off the 50a breakers so have updated my diagram. I think this looks better!

Midnightsun - I am totally loving your idea of making my own cord!!! I will PM you about how to purchase from the company you pointed out in the older string. This could be a total money saver as well as weight! Plus, with me installing a smartPlug at the boat, I can custom make the line to go into a standard 50A/125/250 outlet!!

[bud37]

So here is a read that may apply to some of the grounding......

.https://stevedmarineconsulting.com/neut ... mystified/

There is still something that nags at me.....the boats system was designed for power to be acquired thru two separate shore power cords back to the pedestal, with breakers to protect each separate circuit and by default the cable attached to each.....if that is correct then in this situation there is now one cable and that will not be protected completely because if one breaker trips there is still power running thru the smart plug on the boat thru the other line to and from the pedestal.

Now before adaptors are mentioned , they have some imbalance protection for this inside the large yellow boxes.

Again I am not suggesting this install is all wrong, clearly at this point there has been a very good common sense discussion of the appropriate points with some new concerns clarified........good stuff IMO..