50A shore power with 30A boat?

[Rockinar]

Originally Posted by Hartleyg

And after you shell out for the adapter "pig-tail", be sure to mark it conspicuously with your boat name. I also took some brightly colored paracord and covered ours with a "Cobra stitch" (same thing you make zipper pulls with) so folks are less inclined to "borrow" it because they don't have one (and yes, they WILL try to do that!).
Some marinas will loan you one, but we've found owning one is more reliable



Hartley
S/V Atsa

These pigtails are not cheap. I see how someone would “borrow” one.

[TPG]

Same here, I have a 30A setup which is very common. I use an adapter, and incoming shore power first goes thru a Victron isolation transformer that can take 240/120 voltage and passes only 120V along to Victron MultiPlus Inverter. I have not seen any issues with this setup, and was in a marina recently that only had 50A service.

[plittle2005]

You can easily buy (but it ain't cheap!) a WYE pigtail 50A M to two 30A F. Your boat receptacles probably have 30A breakers or a 30A main breaker for each line further downstream, thus limiting the cord current if shorted. But damage to the cord itself drawing 50A, fried cord....you probably would have needed a new cord anyway!

Just be sure the prong configuration on your pigtail matches the pedestal. See "Tech Data" in https://www.marinco.com/en/products/...apters/Pigtail for a picture of the 120V and 120/250V, as they are different.

[Traumerei]

The trend to only 50 amp shore power at marinas, as was related to me by our marine electrican when he installed 50 amp service on our dock, is because of the increasing number of boats that have come with or installed air conditioning on their boats. It’s very common to see boat requiring two 30amp cords to power both air conditioning and house bank power needs. A single 50 amp outlet and its related circuit breaker is cheaper to install than what had been a typical 50 and two 30 amp outlets.

This past summer, while sailing in Nova Scotia and the North East, this was the norm and having a 50 amp pigtail splitter to two 30amp plugs gave us a lot more flexibility as what slips could accommodate or boat as opposed needing a dock space with dedicated duel 30 amp outlets.

[boat driver]

Originally Posted by Kettlewell

Hard to imagine the scenario that would cause between a 30A and 50A draw on just the cord, and it would have to be outside your boat somewhere along the cord to the power box so I imagine the risk would be pretty small.

from the US marina aspect-
local regulatory laws concerning the dock power have become so ornous that many marinas supply only 50amp 220 service to the slip- among the various regs 15 and 30 amp service require gfi and other various safety devices that are prohibatively expensive to purchase and maintain. Adding this decison is many vessels are ever-hungry for more power and 30amp just does not cover the need.
From the marina perspective- Ample power is supplied and the boat owner via his pigtail takes the responsibilty to step down to 30 amp etc. . This over supply does result in less plug over-heating on the dock end and thereby less problems.
On the boat owner's side- the boat is no longer protected by the dock (30 amp breaker, so if the boat does not have an incoming master 30 amp breaker, the boat can draw excess of the cord's rating (30 amp) and the boat's deck plug and wiring potentially overheats and causes a fire. So it is imperative for the boat owner to educate themselves and understand their boat.

[sinnerman]

https://www.marinco.com/en/p/P503-30...A-125V-Male-to

50 Amp male (shore power) -30 Amp female (boat)

Cheapest found was on Ebay: ($100):
https://www.ebay.com/itm/12565098599...iABEgLQj_D_BwE

Also wholesale marine: https://www.wholesalemarine.com/mari...iABEgJVUPD_BwE

cheers

[OS2Dude]

Originally Posted by Rockinar

Moved to a new Marina. They only have 50A shore power, my boat is 30A.

Amperage is not a problem. You could plug into a 1000 amp source and be fine.

The issue is Voltage. If your boat is only 30 Amps, then it is likely wired for 120V. If the marina pedestal is 220V (Typical for 50A service) then an adapter that will connect to the 220V (4 pin) pedestal connection and split the 220V into two 110V (3 pin) pigtails is what you want. 220V is made of two 110 v circuits in opposite phase. The Neutral wire taps in the center. Positive Hot to Negative Hot is 220V, Positive/Negative Hot to Neutral is 110V. (It does not matter which phase it is.)

Make sure the pins on the adapter ends match the pedestal and your shore power cords. Something like this:https://www.amazon.com/dp/B009IJLVDO...NrPXRydWU&th=1

[Leighpilot]

The outlet can supply 50amps if your boat draws it. The outlet isn’t going to force 50 amps into your boat and blow up your circuits. So get the adapter and connect up in perfect safety.

[bobrosie]

Originally Posted by Hartleyg

And after you shell out for the adapter "pig-tail", be sure to mark it conspicuously with your boat name. I also took some brightly colored paracord and covered ours with a "Cobra stitch" (same thing you make zipper pulls with) so folks are less inclined to "borrow" it because they don't have one (and yes, they WILL try to do that!).
Some marinas will loan you one, but we've found owning one is more reliable



Hartley
S/V Atsa

Real good advice. We were at Annapolis when Hurrican Hugo hit our home in Charleston SC area in 1989. The harbormaster let us tie up our 44' steel yawl but we had to buy an adaptor to keep power on the boat while we drove home in a rental car to assess the damage. Trees down all over the place and power was to be out for several days at least so we drove back to Annapolis to sail the boat home. When we arrived, our adaptor had been stolen! Fortunately the old girl didn't leak too badly and we were't gone long, but I'd love to meet that thief some day before he goes to Hell..

[kubota]

not worried bout the shore cord and pigtail.

but most boats have a fairly long run of interior
cable from the shore power connector to the main ac breaker on the panel.

depending on the vintage of the boat, this wire is probably a 10 gauge in a duplex cable run with other cables. in this common situation it is barely rated 30a and depends on shore power breaker on dock to protect it. if there are series connections, including the ones on the back of the shore power connector, or splices, lots of places to have mildly corroded resistive junctions.

these are inside your boat hidden in lockers and living spaces. , not on the dock in free air where they can cool or be noticed.

a 4 ohm resistive junction on a 30 amp shorted cord will dissapate 3600 watts at breaker trip point without tripping. bout same 2 small space heater in your boat against the interior.

a 50 amp cord will dissipate the same cause the resistance limits it to 30a. however if your corrosion is a bit less, say 2.4 ohms. now you have 6000 watts trying to go somewhere in your boat at the breaker trip point.

the conditions to cause this are rare but not unheard of. .
you would need a load or a short circuit between the shore power connector and some corrosion or cable resistance.

the best recommendation whether on 30a or 50a. is to have a 30a breaker separate from the panel at the point of entry to the boat before the internal wiring.

resistance in shore power connectors driven by mild corrosion is a major source of fires regardless of amperage. keep connections clean and make sure fault protection devices are as close to electrical entry points as possible. if your shore cord shows brown or black discoloration on terminals, you may already have an issue.

the short answer: use the pigtail. its only marginally worse than what you are already living with based on the odds.

someday fix the wiring in the boat with a breaker near the inlet to be safe on 30 or 50. (i have seen some new cords with a breaker right in connector).
and, use a gfci breaker. in the scenarios above it requires a double wire fault with a gfci. . without a gfci a single wire chafed to a ground will do it.

[Sailshabby]

Originally Posted by Tinker Bill

😅

I lived in Honduras for a year(San Pedro Sula). Unfortunately we found housing in one of the ‘newly upgraded’ homes with hot water systems. Couldn’t find the water heater until we tried to shower the next day…two pigtails poking out of the shower head with wire nuts spliced to wires hanging from a hole in the ceiling.

You actually had wire nuts on the splice? High living!!

[sailcrazy]

Following.

[Rockinar]

We now have REVERSE POLARITY issues.

Bought a brand new Marinco 30A shore power cord.
Bought a new Marinco 50A 125v to 30A adapter
Bought a new Marinco 50A 125/250v to 30A adapter.

Shore power pedestal has options of 50A 125 or 50A 125/250v plugs.

I bought both adapters cause it was getting late and I did not have time to go back to West Marine if one did not work so I could try the other and Id have to drive almost 2 hours home instead of staying on the boat.

Neither combo worked. I got red REVERSE POLARITY when I pressed the TEST button on my breaker panel with both adapters.

Im stumped. Marina is pretty new and well maintained.

Anyone think of why its doing this?

[Hartleyg]

The reverse polarity light comes on if the hot and neutral are switched. The fault is likely either at the shore power entrance or at the main breaker on your boat.
With the power DISCONNECTED, swap the hot (should be black) and neutral (should be white) at the entrance connector. Leaving the main breaker off, reconnect the shore power cord(s) and see if the reverse polarity light has gone off. If it has, turn on the breaker and verify proper operation.


Hartley
S/V Atsa


Edit to add: you may want to go over your boat wiring to see if you can identify where the error has occurred and repair it there, instead of just swapping at the entrance (which will help the next guy looking at it!)