Upgrade from two 30 amp to one 50 amp

[Helmsman]

Does anyone have experience with upgrading the electrical system from 30 amp to 50 amp? I am not actively planning this, but a discussion on another forum piqued my interest.

On the surface, it would seem that the following would need to occur:
Change out the inbound outlet to 50 amp.
Change the fuse by the outlet.
Change the wiring to the panel for wire rated for 50 amps (4 wire versus 3 wire of the appropriate size for the amperage and the run).
Ensure the panel is rated for 50 amp service and change out if not.
Would the galvanic isolators need changed?
If a boat has isolation transformers for 30 amp, those would need to be changed out.
And, of course, shore power cables would need to be changed out.

What did I leave out? Any other peripherals need to be considered?

 

[Gdavid]

Single 50 amp 240 V carries more power (12kW) than 2 x 30 amp 120 plugs (7.2kW), so the wiring from the 30 amp inlets to your 120 panel is too small for what you are planning.

I would stick with the two 30 amp inlets as this provides greater flexibility when traveling, if the boat had 240 V appliances already it would be another matter, but I would stick with what you have.

 

[Bacchus]

Biggest question is why are you considering this? Adding more loads or due to pedestal outlet choices limited. If later there are other better ways to accomplish it.

In addition to what you mentioned...
Even if panel is OK to handle 50A 240V you will need to change both main breakers to 50A. Also breakers at inlet will need to be double pole 50A 240V to break both current carrying conductors (I'm assuming that's what you referred to as fuses?)
Yes main wire size to panels ikely needs upgrade.
Check spec for iso- xfmrs but may need upgrade.

Does your panel have spare breakers for addnl loads? If not why upgrade to 50A 240V? Otherwise panel may need to be replaced.
I'm no ABYC certified marine electrician and it might be worth having one review plans, spec equip and inspect even if you do the grunt work to save labor $$$$.

 

[Helmsman]

Biggest question is why are you considering this? Adding more loads or due to pedestal outlet choices limited. If later there are other better ways to accomplish it.

In addition to what you mentioned...
Even if panel is OK to handle 50A 240V you will need to change both main breakers to 50A. Also breakers at inlet will need to be double pole 50A 240V to break both current carrying conductors (I'm assuming that's what you referred to as fuses?)
Yes main wire size to panels ikely needs upgrade.
Check spec for iso- xfmrs but may need upgrade.

Does your panel have spare breakers for addnl loads? If not why upgrade to 50A 240V? Otherwise panel may need to be replaced.
I'm no ABYC certified marine electrician and it might be worth having one review plans, spec equip and inspect even if you do the grunt work to save labor $$$$.

Thanks. Yes, I should have stated breakers, not fuses. I am not upgrading. Merely trying to develop a full list of what would be entailed to do so. I am trying to understand what the full list of changes would entail, to do this if I wanted to do so at some point in the future. If I do, I would an ABYC certified electrician sign off on the work.

I haven’t received the boat yet, and won’t for a few months. The boat is near the maximum outfitting I would consider feasible for a twin 30 amp boat. It does have spare breakers.

The pedestal is a non-issue since the boat will be kept at my home port, has 50 amp service already, as do most of the marinas I frequent.

I appreciate your thoughts, and agree the two main breakers both at the SP inlet and the panel would need addressed.

Anyone think of anything else we might have missed?

 

[Helmsman]

Single 50 amp 240 V carries more power (12kW) than 2 x 30 amp 120 plugs (7.2kW), so the wiring from the 30 amp inlets to your 120 panel is too small for what you are planning.

I would stick with the two 30 amp inlets as this provides greater flexibility when traveling, if the boat had 240 V appliances already it would be another matter, but I would stick with what you have.

Thanks for the input. I am not changing to 50amp 240 volt at this point, anyway. I am merely trying to get an idea of what it would take to get the higher wattage. I agree the wire would need changed. The flexibility you mention is not a big enough issue for me to be too concerned about. I carry y cables and converters for just about every permutation out there.

 

[tiltrider1]

There are multiple ways to accomplish this upgrade.

1). You could pull just one 50a line on your boat. You would need to upgrade your socket, wire all the way to panel, circuit breaker, isolation transformer and possibly your panel. With an isolation transformer there is no need for a galvanic isolator.

2). You could pull both 50a lines but cap them at 30a each. You would need to upgrade your socket, wire to the circuit breaker, you would need to add a second circuit breaker for the second line. You would need a second isolation transformer and you will need to split your panel between the two lines.

You didn’t mention a generator. This could add some complexity depending on the generator and which method you chose.

Option one gives partial operation off a 30a socket to all systems. Option 2 requires either two 30a or a 50a to have operations of all systems.

 

[Helmsman]

There are multiple ways to accomplish this upgrade.

1). You could pull just one 50a line on your boat. You would need to upgrade your socket, wire all the way to panel, circuit breaker, isolation transformer and possibly your panel. With an isolation transformer there is no need for a galvanic isolator.

2). You could pull both 50a lines but cap them at 30a each. You would need to upgrade your socket, wire to the circuit breaker, you would need to add a second circuit breaker for the second line. You would need a second isolation transformer and you will need to split your panel between the two lines.

You didn’t mention a generator. This could add some complexity depending on the generator and which method you chose.

Option one gives partial operation off a 30a socket to all systems. Option 2 requires either two 30a or a 50a to have operations of all systems.

There is a NL generator on board. What complexity do you see?

The boat comes with isolation transformers for two 30 amp circuits. If I were to ever go down this path, I would probably pull them, and put a galvanic isolator for the two inbound load lines. The 50 amp isolation transformers are heavy and bulky. Not sure it would be worth it to me to have the larger one.

 

[tiltrider1]

There is a NL generator on board. What complexity do you see?

The boat comes with isolation transformers for two 30 amp circuits. If I were to ever go down this path, I would probably pull them, and put a galvanic isolator for the two inbound load lines. The 50 amp isolation transformers are heavy and bulky. Not sure it would be worth it to me to have the larger one.

The NL will adapt to either method, worst case would be changing jumper wires. I think you are confused about galvanic isolators. GI’s give you some protection from stray DC on the AC ground wire. Isolation Transformers allow you to not have a ground wire and deals with any out of balance issues with your neutrals.

 

[psneeld]

I have done it and it probably cost about $4-5,000 total. The new panel alone was $3500 but I just wanted new a completely new AC/DC panel, didn't want to wire up myself...and wanted nice lighting, new breakers and digital amp/volt meters on both voltages.

I wouldn't begin to try and explain the complexities of assembling a new system in simple posts. Be happy to answer specific questions, one or two at a time.

If you haven't spent months or more investigating ABYC concepts and other electrical peculiarities and have a pretty good idea up front what is the good the bad and the ugly .... then I suggest hire a pro to at least lay out the components for you, you do the work, then hire the guy to come back and look over the work you did.

As a liveaboard full time for many years...with 2 people on board who like their electrical comforts of home.... yes a 50A upgrade to me was worth every penny.

And anyone who says I really don't need a TV and all that stuff on a boar will wish they never lectured me on that note.

 

[Gdavid]

I know you said this would be a later project but the builder could probably do it cheaper for you. Helmsman bent over backwards for member N4061.

 

[Helmsman]

The NL will adapt to either method, worst case would be changing jumper wires. I think you are confused about galvanic isolators. GI’s give you some protection from stray DC on the AC ground wire. Isolation Transformers allow you to not have a ground wire and deals with any out of balance issues with your neutrals.

Thanks. Not confused at all. The boat comes with two Victron Isolation transformers for 30 amp service. There is a connection for the ground wire in, and the ground wire out to the panel. If I were to go to a single 50 amp feed, then the two 30 amp Victron isolation transformers will not work with the 50 amp service.

Rather than replace the two of them, I would add a galvanic isolator to limit galvanic corrosion and forgo the advantages of an isolation transformer.

 

[Helmsman]

I have done it and it probably cost about $4-5,000 total. The new panel alone was $3500 but I just wanted new a completely new AC/DC panel, didn't want to wire up myself...and wanted nice lighting, new breakers and digital amp/volt meters on both voltages.

I wouldn't begin to try and explain the complexities of assembling a new system in simple posts. Be happy to answer specific questions, one or two at a time.

If you haven't spent months or more investigating ABYC concepts and other electrical peculiarities and have a pretty good idea up front what is the good the bad and the ugly .... then I suggest hire a pro to at least lay out the components for you, you do the work, then hire the guy to come back and look over the work you did.

As a liveaboard full time for many years...with 2 people on board who like their electrical comforts of home.... yes a 50A upgrade to me was worth every penny.

And anyone who says I really don't need a TV and all that stuff on a boar will wish they never lectured me on that note.

Thanks for the costs. I would assume that didn’t include the new 50 amp SP cables?

I have studied ABYC electrical standards for years, with a particular emphasis on electrical, and may take the upcoming course they offer in September just as a refresher. I would employ a certified ABYC electrician, to review and approve the plan, and then to check my work. I don’t think I will go this route, at least until I have used the boat for a year or two, and get a good feel for how the electrical system performs over time.

The purpose of the OP was to get an idea of what is involved and whether I am missing any of the big parts of the process. So far, the outlet, the breakers on both ends, the AWG of the cable, the elimination or replacement of the isolation transformer, the addition of the galvanic isolator in lieu of the isolation transformers, and the panel capacity and buss bars.

I also have a Victron inverter charger coming on the boat. I don’t think that is an issue, since it has a feeds to and from the panel, and I don’t think it cares about the main feed amperage’s.

 

[Helmsman]

I know you said this would be a later project but the builder could probably do it cheaper for you. Helmsman bent over backwards for member N4061.

We have already discussed that with them. And, yes they would have been more than happy to. I decided on the 30 amp and I am ok with that. The purpose of this discussion was to obtain an “inventory” of the pieces needed, if I find after a couple of years that I am not happy with my decision. I have some down time over the next month, and wanted to use the time productively. This is one of the assessments I wanted to complete, and have in my back pocket. Doubt I will ever change to it, but it doesn’t hurt to know what it would take.

 

[tiltrider1]

Some clarification. You are currently set up for two 30a 125v and you are thinking of upgrading to a 50a 125/250v. Is this correct.

I got the impression that you were going from single 30a 125v to 50a 125v.

 

[psneeld]

Thanks for the costs. I would assume that didn’t include the new 50 amp SP cables?

I have studied ABYC electrical standards for years, with a particular emphasis on electrical, and may take the upcoming course they offer in September just as a refresher. I would employ a certified ABYC electrician, to review and approve the plan, and then to check my work. I don’t think I will go this route, at least until I have used the boat for a year or two, and get a good feel for how the electrical system performs over time.

The purpose of the OP was to get an idea of what is involved and whether I am missing any of the big parts of the process. So far, the outlet, the breakers on both ends, the AWG of the cable, the elimination or replacement of the isolation transformer, the addition of the galvanic isolator in lieu of the isolation transformers, and the panel capacity and buss bars.

I also have a Victron inverter charger coming on the boat. I don’t think that is an issue, since it has a feeds to and from the panel, and I don’t think it cares about the main feed amperage’s.

Probably the cable was included...just remember if you do it right...the nickel and dime things kill you...the shrink tubing, the cable terminal ends, the wire ties/cable clamps, etc...etc....

 

[Helmsman]

Some clarification. You are currently set up for two 30a 125v and you are thinking of upgrading to a 50a 125/250v. Is this correct.

I got the impression that you were going from single 30a 125v to 50a 125v.

That is my fault. I should have been clearer. The idea would be to go to a single 50 amp 125/250v from two 30 amp 125v inlets.

 

[Helmsman]

Probably the cable was included...just remember if you do it right...the nickel and dime things kill you...the shrink tubing, the cable terminal ends, the wire ties/cable clamps, etc...etc....

Yep. I would need to add that to the specs. thank you.

I have most of that from previous work I have completed. Most of my electrical work has been electronics, which sometimes entails branch circuits.

 

[tiltrider1]

That is my fault. I should have been clearer. The idea would be to go to a single 50 amp 125/250v from two 30 amp 125v inlets.

Ok, that makes it clear.

You would need a new socket, circuit breaker, wire from socket to panel, (isolation transformers or removal of), and your panel would need to be rated to handle 50a.

Just a reference point. I use 50a 125/250v. Most the summer I can run the boat off of 30a. I only need the second leg for running the Dryer and it pulls less than 30a. It is only very hot days were I am running 3 air conditioners that I ever pull more than 30a on the second leg. In winter it is not uncommon to pull 40a to heat the boat and on very cold days I might pull 40a on both sides if the water heater is on.

 

[Helmsman]

Ok, that makes it clear.

You would need a new socket, circuit breaker, wire from socket to panel, (isolation transformers or removal of), and your panel would need to be rated to handle 50a.

Just a reference point. I use 50a 125/250v. Most the summer I can run the boat off of 30a. I only need the second leg for running the Dryer and it pulls less than 30a. It is only very hot days were I am running 3 air conditioners that I ever pull more than 30a on the second leg. In winter it is not uncommon to pull 40a to heat the boat and on very cold days I might pull 40a on both sides if the water heater is on.

I think I will be fine. I have two AC’s (used for heat also), an induction cooktop, convection microwave, and an electric grille on the FB. Obviously, with all of that and the hot water heater, I will need to load balance sometimes.

A friend of mine who is buying the Helmsman 43E will have three AC’s with the rest the same, and will be having the 50 amp 125/250v service.

 

[Pau Hana]

I did exactly what is being asked about- went from 2 30A inlets to a single 50A 125/250V inlet via a Charles Iso transformer that split the incoming power into 2 50A 125V lines.

It's been working perfectly since install.

https://www.trawlerforum.com/forums...evice-charles-isolation-tranformer-44649.html

 

[Helmsman]

I did exactly what is being asked about- went from 2 30A inlets to a single 50A 125/250V inlet via a Charles Iso transformer that split the incoming power into 2 50A 125V lines.

It's been working perfectly since install.

https://www.trawlerforum.com/forums...evice-charles-isolation-tranformer-44649.html

Thanks for the Link to your discussion. That helped quite a bit. Now I will need to get my arms around the issue Steve D came up with on boosting versus non-boosting isolation transformers.

 

[tiltrider1]

Thanks for the Link to your discussion. That helped quite a bit. Now I will need to get my arms around the issue Steve D came up with on boosting versus non-boosting isolation transformers.

You only need boosting if you are running 220 appliances. It’s a phase issue. Meaning you will see 125v from each leg but if you put the two legs together you only get 208v not 250v at some locations do to the Y transformer being 120 degrees out instead of 180 degrees out of phase.

 

[boating rich]

Thanks for asking this question. I was wondering the same since it seems like marinas look at us strangely with two 30 amp cords. Good discussion.

 

[Helmsman]

You only need boosting if you are running 220 appliances. It’s a phase issue. Meaning you will see 125v from each leg but if you put the two legs together you only get 208v not 250v at some locations do to the Y transformer being 120 degrees out instead of 180 degrees out of phase.

Ok, that makes sense.

 

[boating rich]

I have been following the discussion and wondering why is the suggestion to switch the panel and everything over to 50 amp. I currently have two 30 amp cords which each feed half of my panel. We usually have a pigtail which connects the two 30 amp cords to the pedestal. Couldn’t we just convert to having a single 50 amp cord from the boat to the dock and then have something that effectively splits the power inside the boat to two 30amp feeds which feed the existing panel just like the pigtail did?

 

[backinblue]

I'm trying to understand why this would be an upgrade. If you needed to plug into a 50 amp outlet, could you not use a Y cord to connct your (2) 30 amp plugs intop (1) 50 amp? Maybe I'm not understanding completely what would make you want to do this.

 

[ranger58sb]

Thanks. Not confused at all. The boat comes with two Victron Isolation transformers for 30 amp service. There is a connection for the ground wire in, and the ground wire out to the panel. If I were to go to a single 50 amp feed, then the two 30 amp Victron isolation transformers will not work with the 50 amp service.

Rather than replace the two of them, I would add a galvanic isolator to limit galvanic corrosion and forgo the advantages of an isolation transformer.

I'd think it'd be cost effective to replace the two 30A isolation transformers with a single 50A isolation transformer.

Assuming afterwards sell-off of the 30s.

-Chris

 

[ranger58sb]

I have been following the discussion and wondering why is the suggestion to switch the panel and everything over to 50 amp. I currently have two 30 amp cords which each feed half of my panel. We usually have a pigtail which connects the two 30 amp cords to the pedestal. Couldn’t we just convert to having a single 50 amp cord from the boat to the dock and then have something that effectively splits the power inside the boat to two 30amp feeds which feed the existing panel just like the pigtail did?

I'm trying to understand why this would be an upgrade. If you needed to plug into a 50 amp outlet, could you not use a Y cord to connct your (2) 30 amp plugs intop (1) 50 amp? Maybe I'm not understanding completely what would make you want to do this.

OP's concern is about power limitations. Ability to power everything on the boat simultaneously. (As I understand it.)

Twin 30As connected to a 50A/250 pedestal via a "Smart Y" only supplies 2x 30A feeds to the boat.

Compare to actual 50/250VC service which supplies 2x 50A feeds.

(And if the panel isn't already designed for 50A input... )

-Chris

 

[backinblue]

My understanding is that isolation transformers are preferred over galvanic isolators. That aside, how is going from 60 amp available power to 50 amp, an upgrade? He wants to go from (2) 30 amp to (1) 50 amp.

 

[Helmsman]

Several questions regarding why I would consider moving from 30 amps to 50 amps. To understand why it would be an advantage requires a little math.

A 30 amp feed supplies 30 amps x 120volts equaling 3,600 watts. Since the boat has two 30 amp feeds, that equates to 7,200 watts of available power. A single 50 amp 120/240 volt feed has two load lines. So, the math there is 2 x 50 amps x 120 volts or 12,000 watts.

Therefore the change would be entirely motivated by getting more power on the boat from the available shore power. That would provide the ability to run more high amperage equipment at the same time. With the equipment I have spec’ed for the boat, I am at close to the upper end of the power capacity for two 30 amp feeds. It is entirely and completely a convenience thing.

The discussion has zero to do with with what type of connection is available at a particular dock. I have a 50 amp pedestal at my home dock. While there are some docks out there which have limited electricity available, there are very few out there that don’t have the industry standard 50 amp or 30 amp available. These can be used with either service (for the most part) on the boat, by using adaptors for either. With two 30 amp connectors on a pedestal, there will be the wattage constraint illuminated above in terms of how much amperage is available. Not a big deal, as many 50 amp boats deal with that as they travel. So, availability of one or the other is a moot point, for me, at least.

I hope that helps.