110/250 power question

[Troy Boone]

Hi everyone,

First time sailboat owners here with a new-to-us 2003 Valiant 42. The inlet where we plug the shorepower line into the boat is 50 amp 110 volts, and the 50 amp outlet on our dock is 110/250. No combination of new lines, adapters, etc. seems to work (I've bought and borrowed and returned too many to list) and anyway it seems best to me to have a system that doesn't require too much adaptation, pigtails, etc.

The local advice I've gotten so far is that this will not just be an issue at our marina but when we start traveling, and so we should upgrade out boat with a new 110/250 inlet in the cockpit (and a new shorepower cord of course) so we can plug in with no worries.

Curious if sailors who have travelled more than we have would agree that our 110v boat is antiquated and we should catch up to the 110/250v world.

I'm nobody's idea of an electrician, so additional advice around the issue is welcome too.

Thanks!

Troy

[tml]

Great question interested in the replies

[Chuck34]

Been there…done that. Best advice, have power cords made up with 125-50 amp female ends with 125-30 amp male ends. All marinas have 125-30. Very few have 125-50, if any.

[Chuck34]

Reading this again, I’m curious as to what the previous owner did to power the boat. I might ad I’m surprised a 2003 boat is wired for 120 volt, 50 amp. If it had been built back in the 80’s, I would understand as that power option was somewhat available at marinas and some boat builders were offering that configuration but not in more recent years.
What power cords came with the boat and what did your surveyor have to say bout it?

I used to have a 1988 boat that was built to handle 120-50 amp, but the previous owner did what I suggested and had power cords made…30 amp male end and 50 amp female. Made life simple and we could plug into any marina as all offer 120-30

[Jammer]

120v-50a is not a standard configuration. You have three choices:


1) You can make up a cord that goes from your 120v-50a inlet to a 120v-30a shore power connection, and make up another cord that goes from your 120v-50a inlet to a 120/240v-50a shore power connection. The 120v-30a connection is the most common shore power connection to encounter in the USA. These will work fine but you will only get 30a, which means you can't do things like run the air conditioning and the water heater at the same time. The idea is that you use whichever cord matches the shore power facilities that are available. 120v/240v-50a are rare but do exist on larger slips.



2) You can have a marine electrician redo the wiring so you have two 120v-30a shore power connections with half the loads on one and half on the other. This is the most common configuration now for boats that size that need more than a single 120v-30a can provide. This will be expensive but will give you the most flexibility in the long run, if you intend to use shore power extensively, and intend to run the air conditioning.



3) You can have marine electrician reconfigure the shore power on your boat for 120v-240v/50a, which will also be expensive and not as flexible as two 30a cords, but will work.

[Chuck34]

One big question that only the OP can answer…does the boat have 1 power cord inlet or 2? On a 42 footer, I would hope it has 2. If so, a lot of appliances can be run on 2, 30 amp power cords, meaning, the easiest and cheapest route to go is having power cords made with 30 amp male and 50 amp female ends.
If only 1 inlet, power management will be necessary but workable. Rewiring the boat is an option but expensive.

[smac999]

You should be able to get an adapter. But 50a 120v is not comon at all.

I would replace the boat inlet with a 50a 120/240 inlet and only connect 1 hot. And use a 50a 240 shore cable. So you will get 50a 120v from a 50a 240v dock. No changes needed to boat wiring. Just Saves you from needing the adapter everywhere.

The issue is at 40’ 30 120v amps docks will probably be more common then 50a 240. So have a 30- 50a adapter too. You’d only get 30a. Don’t bother with a dual 30 y to 50a cord adapter. It will not help you.

[smac999]

Or just buy this

https://www.marinco.com/en/p/123A/Pi...5-250V-Male-To

And plug your boat into a 50a 240v dock.

With a 50a 120 cord or 50a 240v cord. Just changes which end the adapter goes on. The 120v cord will be lighter with 1 less wire

[Sailmonkey]

Your 50a-125v cord is odd. Docks still exist with this connection but they’re disappearing everyday.

There is an adapter, as pointed to above.



But you’ll spend most of your time with it attached.

If you really need 50a service I’d just replace the cord end with the 125/250v cold end and only use one of the hot leads.

[ranger58sb]

Originally Posted by Troy Boone

Hi everyone,

First time sailboat owners here with a new-to-us 2003 Valiant 42. The inlet where we plug the shorepower line into the boat is 50 amp 110 volts, and the 50 amp outlet on our dock is 110/250. No combination of new lines, adapters, etc. seems to work (I've bought and borrowed and returned too many to list) and anyway it seems best to me to have a system that doesn't require too much adaptation, pigtails, etc.

The local advice I've gotten so far is that this will not just be an issue at our marina but when we start traveling, and so we should upgrade out boat with a new 110/250 inlet in the cockpit (and a new shorepower cord of course) so we can plug in with no worries.

Curious if sailors who have travelled more than we have would agree that our 110v boat is antiquated and we should catch up to the 110/250v world.

I'm nobody's idea of an electrician, so additional advice around the issue is welcome too.

Thanks!

Troy

I glanced briefly at your dock outlets before your boat arrived in that slip, and thought they were straight-forward 30A/125V outlets. I apparently didn't look closely enough...

Some marinas will rewire an outlet for your slip; you might ask...

But... that doesn't solve transient slips you might visit...

And it's not so much an "antiquated" thing. Your system is viable, but it's just that most marinas these days give you a choice of 50A/250V or 30A/125V outlets. The boat only has a single 50A/125V shorepower inlet? The 50A/250V dock supply can give you one leg of 50A/125V easily enough... and if that's what your Valiant wants.... assuming your on-board breaker is 50A and the rest of your systems are appropriate sized for a 50A feed...

Then either the adapter smac linked, or a purpose made shore-power cord seem to be satisfactory... probably no need to leap through hoops.

(Changing the inlet on your boat would mean you have two legs of 50A/125V power available to the boat... but if the boat wiring/panel isn't designed to take advantage of the extra 50A/125V line... that doesn't seem like any significant improvement. Especially since 50A/250V shorepower cord is HEAVY.)

Also, since 30A/125V dock supplies are also common, you might want an adapter that converts from that at the pedestal to your 50A/125V shorepower cord, too. (I assume there is one; haven't looked.) That wouldn't get you a 50A supply, only 30A... and at that point you might have to do some load management... but it could be a decent back-up if you land at a transient dock someplace where they don't happen to have an available 50A/250V supply.

-Chris

[AKA-None]

In the US I thought all many 50 amp services were 4 wire?

[Sailmonkey]

Originally Posted by AKA-None

In the US I thought all many 50 amp services were 4 wire?

Nope.

The 50a125v service is three wire Hot, Neutral, Ground.

The 50a125/250V service is 4 wire H,H,N,G.

[smac999]

Originally Posted by AKA-None

In the US I thought all many 50 amp services were 4 wire?

I think 120v 50a was a thing in the 80's... with maybe a few boats and docks left. I have only ever seen 1 boat with it.