50 amp shore power connector but 30 amp breaker at the panel - what do I need to change?

Alaris

Super Anarchist
1,840
657
Annapolis
Bottom line is you have to check that you have sufficient wire gauge to go from the breaker you want to switch to 50A (from the 30A currently), to the next set of breakers (for each branch circuit).
Eventually when you get the boat, if you can verify that the wire between the 30A breaker and the distribution buses that feed those smaller breakers can handle 50A vs 30A, and the bus itself is ok for 50A, then you're good to swap the breaker and install a galvanic isolator (if you don't already have one).
Got it. Thanks!
 

longy

Overlord of Anarchy
6,985
1,279
San Diego
No, he needs to inspect the entire circuit ALL THE WAY from where power comes on board. It has been established that the schematic is NOT accurate, and who knows what has been done over the years since construction.
Bringing the boat up to current ABYC standards with a breaker right at shore power inlet & galvanic isolator are optional, but HIGHLY recommended.
 

Alaris

Super Anarchist
1,840
657
Annapolis
Forgive my skepticism but the ELCI and galvanic isolator combined are going to run nearly a grand and are optional? Pass
 

slug zitski

Super Anarchist
7,089
1,465
worldwide
No, he needs to inspect the entire circuit ALL THE WAY from where power comes on board. It has been established that the schematic is NOT accurate, and who knows what has been done over the years since construction.
Bringing the boat up to current ABYC standards with a breaker right at shore power inlet & galvanic isolator are optional, but HIGHLY recommended.
Yah

long time since I’ve sailed a boat that didn’t have an ac isolation transformer and a pair of breaker , fuse , GFCI

F240938C-305A-417E-9501-7C9BF4D1E8AA.png
 

longy

Overlord of Anarchy
6,985
1,279
San Diego
Galvanic isolator:
Input breaker with ground fault protection:
Input breaker (no GFI)

Breakers & isolators are HIGHLY recommended. Ask your insurance agent. And lack of these should have been noted on any survey

One boat buck for large safety increase
 

Alaris

Super Anarchist
1,840
657
Annapolis
Galvanic isolator:
Input breaker with ground fault protection:
Input breaker (no GFI)

Breakers & isolators are HIGHLY recommended. Ask your insurance agent. And lack of these should have been noted on any survey

One boat buck for large safety increase
The boat was built in 83. It wasn’t required to have them. None of our other boats have them either.
 

longy

Overlord of Anarchy
6,985
1,279
San Diego
They just didn't know better back then. Cars didn't have seat belts or air bags either. You are doubling the amperage into the boat.

In the end, it is your boat & crew.
 
  • Like
Reactions: Mid

Alaris

Super Anarchist
1,840
657
Annapolis
What do they actually do? The articles I’ve read talk about electrocuting someone in the water. Give me a break. No one swims near this pier.
 

longy

Overlord of Anarchy
6,985
1,279
San Diego
^^^ Normally the ground wire is not run through a breaker (to ensure constant safety) and is allways directly connected to dockside circuit. IF somewhere else on that circuit there is a leak/short to ground that current is now present on the ground wire and therefore is present on your boat. So a person contacting anything grounded (almost all outside surfaces of a AC user) they can be shocked. This current will also seek to escape to the water via whatever metals contact the water. This will cause very active electrolysis to those metals ( to failure & water ingress) If the current IS leaking to water, there will be a danger sphere around that fitting where a person in the water can be electrocuted (danger zone bigger in fresh water than salt water)
 

Alaris

Super Anarchist
1,840
657
Annapolis
If I’m installing all new wiring on the dock with all required safeguards there, why do I also need them on the boat?
 

climenuts

Anarchist
742
301
PNW
Are you always plugging into the same plug or are all plugs you will ever plug into known to have all necessary safeguards?

There's never a diver to clean your or a neighbors bottom, change anodes, etc? Nobody has ever fallen overboard at the dock?

$1k for an isolation transformer is pretty cheap insurance on all kinds of galvanic corrosion & electrocution issues which could occur.
 

Alaris

Super Anarchist
1,840
657
Annapolis
You guys act like $1k is nothing for something that is one in millions’ chance of happening. I’m not going to argue any more.

Thanks to those who have provided useful input on my questions.
 
Last edited:

mckenzie.keith

Aspiring Anarchist
846
281
Santa Cruz
The galvanic isolator is probably a good idea for electrolysis. Yandina GI-50 is around 140 bucks US.

ELCI on the dock is a good idea (and probably required by code). I don't see how adding ELCI to the boat provides any additional protection compared to ELCI on the dock, although if you go to another dock somewhere else that doesn't have ELCI then having it on your boat would theoretically help make things safer.

I have to admit I would probably come to the same conclusion as you about the isolation transformer. It is a lot of money and weight.

You should use GFCI outlets on the boat. Maybe they already are. If not, replace with GFCI as the existing ones go bad over time.
 

Alaris

Super Anarchist
1,840
657
Annapolis
The galvanic isolator is probably a good idea for electrolysis. Yandina GI-50 is around 140 bucks US.

ELCI on the dock is a good idea (and probably required by code). I don't see how adding ELCI to the boat provides any additional protection compared to ELCI on the dock, although if you go to another dock somewhere else that doesn't have ELCI then having it on your boat would theoretically help make things safer.

I have to admit I would probably come to the same conclusion as you about the isolation transformer. It is a lot of money and weight.

You should use GFCI outlets on the boat. Maybe they already are. If not, replace with GFCI as the existing ones go bad over time.
The boat has all brand new GFCIs.
 

SimonGH

Member
429
96
Westbrook CT
No, he needs to inspect the entire circuit ALL THE WAY from where power comes on board. It has been established that the schematic is NOT accurate, and who knows what has been done over the years since construction.
Bringing the boat up to current ABYC standards with a breaker right at shore power inlet & galvanic isolator are optional, but HIGHLY recommended.
^^ yes, sorry, I meant to say that - all the way from the new shore power inlet.

I would argue the galvanic isolator is relatively inexpensive insurance - they are not the same cost as an isolation transformer. The PO of my boat had to replace the saildrive because of galvanic corrosion... that was a lot more $$$ than an isolator...


So ideally the wiring is all ok (from inlet to distribution bus bars), so you can simply change out the shore power connector on the boat (since you want to use the smart connector), swap the double pole breaker to 50A, and just break the ground coming from the shore power inlet with a galvanic isolator.

The location of the 50A breaker is supposed to be close to the shore power inlet, but I believe you can claim you're "grandfathered" in with it's location. However, you can simply use a DIN breaker and DIN power enclosure - far cheaper than that bluesea system and completely acceptable (it's what Beneteau used on my 2019 41.1)


you may want to also put GFCI breakers in the feed for the AC system:

 

Alaris

Super Anarchist
1,840
657
Annapolis
^^ yes, sorry, I meant to say that - all the way from the new shore power inlet.

I would argue the galvanic isolator is relatively inexpensive insurance - they are not the same cost as an isolation transformer. The PO of my boat had to replace the saildrive because of galvanic corrosion... that was a lot more $$$ than an isolator...


So ideally the wiring is all ok (from inlet to distribution bus bars), so you can simply change out the shore power connector on the boat (since you want to use the smart connector), swap the double pole breaker to 50A, and just break the ground coming from the shore power inlet with a galvanic isolator.

The location of the 50A breaker is supposed to be close to the shore power inlet, but I believe you can claim you're "grandfathered" in with it's location. However, you can simply use a DIN breaker and DIN power enclosure - far cheaper than that bluesea system and completely acceptable (it's what Beneteau used on my 2019 41.1)


you may want to also put GFCI breakers in the feed for the AC system:

Okay, this is helpful.

Putting in a new breaker box closer to the inlet brings me back to an earlier idea: sending a 125/250 feed to two 120V circuit breakers (instead of just taking one leg as is currently done). One would feed (through the original 3 wires) the existing 30A panel. The other would have a new 30A breaker just for my air conditioner wired directly to this new panel containing the ELCI breaker. Then I can mollify the critics with an ELCI breaker while accomplishing my goal of a new dedicated circuit for the air con. That would work, right?
 

SimonGH

Member
429
96
Westbrook CT
Yes, that's exactly how I installed AC on my 41.1. The only difference is that I put in a separate 30A power inlet, you're just going to split the 50 into two separate.

I think the ELCI is a requirement on the shore side. I think the boat side can just have a regular GFCI, so you just use 2 30A GFCI DIN breakers. But things may have evolved since 2019?
 

Alaris

Super Anarchist
1,840
657
Annapolis
Yes, that's exactly how I installed AC on my 41.1. The only difference is that I put in a separate 30A power inlet, you're just going to split the 50 into two separate.

I think the ELCI is a requirement on the shore side. I think the boat side can just have a regular GFCI, so you just use 2 30A GFCI DIN breakers. But things may have evolved since 2019?

Okay I’ve thought more about this and I don’t think I need both 240 legs because that’s 100A of 120 which is way more than I need. Instead, I would use Blue Seas 3118 breaker and box (https://www.bluesea.com/products/31...C___50A_ELCI_Main_-_2_blank_circuit_positions) which has two extra breaker positions. Does this make sense? Sorry about the drawing. I left off the wiring for the reverse polarity indicator. The diagram for the box is here: https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/instructions/980009850.pdf

I am not sure how the ELCI breaker would connect to the other two breakers so that part of the drawing is probably wrong.

Also I suppose the HVAC breaker could be 30A as well, I don’t know what the correct breaker size is for a startup draw of 17A.

90D7C5F4-F9FC-4336-96BA-E82AC9CA04DE.jpeg
 
Last edited:

Slick470

Super Anarchist
2,054
322
Virginia
If the starting draw is 17A, does the data sheet for the HVAC list a max breaker size or MOCP? A 20A may be ok, but depending on the unit, you may have nuisance tripping if it's too close.
 




Top