Two 30 amp cables but only one dock receptacle

Again, I was assured that there are no stupid questions on here! So here goes. My boat uses two 30-amp shore power cables (one for the aft cabin air conditioner and the other for the rest of the boat). I figure that in a marina I will most likely find either one 30-amp receptacle or one 50-amp receptacle. So, short of being able to also use a 30-amp receptacle from another (vacant) slip, any suggestions on how best to cope with this? (I do not mind buying something else, but am not sure what to buy).
.
John
(Now a member, I guess, but really still a newbie)

Get a Y cable that goes from a 50 amp at 250 volts connector to two split cables each having 30 amps at 125 volts connectors. These can be expensive (~ $250 new) so you might look for one on ebay or craig's list.

You'll need a 50 amp power cable and a splitter cable to make that into two 30 amp plugs.

I just bought that exact setup. The whole works was $850.

BTW the 50 amp shore power cable weighs a ton!

The danger in using a power box from the next slip is most docks are wired for 240V

This is done with 2 120v legs .

With Either the Y or just plugging in next door , there is a could be 240V on board .

Messing with anything electrical might expose the full 240V to someone not expecting it.

The Y setup is safer as the neutral (white wire ) and ground (green wire) will come from the same source.

No guarantee when you grab the next slips power box, as it could easily be from a different dock power line.

I think he is saying there is only one 30amp plug at his slip not a 50

motion30 said:

I think he is saying there is only one 30amp plug at his slip not a 50

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No, he is speculating on what he might find at any marina he might choose to stay at.

Many times, there will be two 30 amp receptacles on each dock pedestal so he would be fine unless another boat is using the extra one. Sometimes, a marina will only have 50 amp receptacles available. I carry an adapter for this situation but I have a single 30 amp inlet on my boat.

The OP will need a 50 amp single to two 30 amp "Y" adapter. It's a common item available at most any marine store or vendor. It plugs into the 50 amp receptacle and has two short cords with sockets on the ends for his 30 amp power cords to plug into.

http://www.defender.com/product.jsp?path=-1|328|299260|319692&id=1353795



In a pinch, he can just not use the cable that powers the airconditioner. He'll still have everything else working.

We have used this: It's a y adapter with two-30 amp female to one-30 amp male. It feeds from one 30 amp shore power cord to the 2-30 amp circuits at the boat. It allows us to use both 30 amp circuits and to run 1 of the AC units if we shut off the hot-water heater and are careful not exceed 30 amps total for the boat. If we do, there is over-current protection at the pedestal (assuming that's wired correctly).

Larry M said:

We have used this: It's a y adapter with two-30 amp female to one-30 amp male. It feeds from one 30 amp shore power cord to the 2-30 amp circuits at the boat. It allows us to use both 30 amp circuits and to run 1 of the AC units if we shut off the hot-water heater and are careful not exceed 30 amps total for the boat. If we do, there is over-current protection at the pedestal (assuming that's wired correctly).

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If he is plugging into a 30 amp dock outlet this is the safest method. Just watch your loads. (my boat has a switch inside that combines the inlets for this situation)

If he is plugging into a 50 amp outlet then he he should have a 50 amp power cord and a 50-30 wye splitter. (This is the method I chose.)

Am alternate and cheaper method for the 50 amp dock outlet would be to hve the 50-30 wye splitter feeding two 30 amp power cords. (Personally I'd rather use the 50 amp cord but this method will work.)

If your cheap like me, on our prior boat I had the battery charger on plug that I could put on the same leg as the A/C shore power and in most cases I could run the house needs of the inverter saving the cost of the second shore service.

Larry M said:

We have used this: It's a y adapter with two-30 amp female to one-30 amp male. It feeds from one 30 amp shore power cord to the 2-30 amp circuits at the boat. It allows us to use both 30 amp circuits and to run 1 of the AC units if we shut off the hot-water heater and are careful not exceed 30 amps total for the boat. If we do, there is over-current protection at the pedestal (assuming that's wired correctly).

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I think this is what I was looking for. Wonder why those things are so doggoned expensive? (Answer: Everything for a boat is expensive!

Larry M said:

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Been meaning to get one of these for a while. Only $125 at Defender.

ksanders said:

Am alternate and cheaper method for the 50 amp dock outlet would be to hve the 50-30 wye splitter feeding two 30 amp power cords. (Personally I'd rather use the 50 amp cord but this method will work.)

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Since the OP already has the two 30 amp cords, this method will be quite a bit cheaper.

GonzoF1 said:

Been meaning to get one of these for a while. Only $125 at Defender.

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Can anyone give me a part number at Defender? This is absolutely what I need.

I'm upgrading to a 50 amp service...you can always take less but after my 3rd live aboard...having a 50 amp service is almost a necessity to keep from going crazy shifting loads all the time. Its like having a 3rd, 30 amp cord plus a little more available.

Maybe I'm missing something here. The marina where I (will) keep the boat only offers 30 amp receptacles. So how can I upgrade?

jwnall said:

Maybe I'm missing something here. The marina where I (will) keep the boat only offers 30 amp receptacles. So how can I upgrade?

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You have to get the marina to do the upgrade.

Its not that hard in many cases. In the power box they would either replace your 30 amp outlet and breaker with a 50 amp unit, or they would just add a 50 amp service to it.

Some marinas will do it if you pay to have it done, some are less flexible

I have found that most marinas are more likely to have 1 50 Amp socket than two 30 Amp sockets. I carry the adapter. In one case, they charged $5 for a 30 amp connection and $8 for a 50. And stupidly, when asked what I required, I replied "two 30s" and so they charged me ten bucks for two 30s when I could have just used the adapter to turn one 50 into two thirties. Now I just say I will take anything. Worst case if they have only one 30, and if is hot then I use that one for A/C and run the rest of the boat off of 12V in a pinch.

jwnall said:

I Wonder why those things are so doggoned expensive?

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Because the market for this stuff is relatively small and there is an almost virtual monopoly (in this country) on the components. So they charge what the market will bear.

One way to potentially save a fair amount of money is to have the adaptors you need made up by an electrical shop. The shop gets the components at wholesale cost, which is WAY less than retail. It takes very little time to make up the adaptors and cables so the labor cost is low. In our case we have reduced the cost of a groundpower cable and 30-50 amp, 30-20 amp, and 30 amp-120 Edison adaptors by at least half over buying the same adapters ready made.

Most recently we needed a 50 amp male to 30 amp female adaptor. As far as I know an adaptor of this type is not even available pre-made. And the off-the-shelf components to make one totalled over $200. The shop we use made it up for us for $100 using the same components.

So before you plunk down your credit card at the West Marine/Defender/Fisheries/etc. store you might check with your local marine electric shop (if you have one). It may be you can get the same thing for a lot less.

".having a 50 amp service is almost a necessity to keep from going crazy shifting loads all the time."

Sounds like another place for a couple of load shedding automatic relays.

jwnall said:

Can anyone give me a part number at Defender? This is absolutely what I need.

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You betcha!

Furrion Y Adapter (2) 30 Amp Female to (1) 30 Amp Male

Tom-

jwnall said:

Maybe I'm missing something here. The marina where I (will) keep the boat only offers 30 amp receptacles. So how can I upgrade?

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You can still use a 30 amp dock receptacle or 2 and "Y" them into your 50...you will still only draw 60 amps (or only 30 if using one leg) instaed od 100 (2x50) with a 50 cord...the nice thing is you CAN draw all that power when it IS available without worrying about loads.

Weekenders big deal but liveaboards all year get tired quickly of shedding loads..

FF why shed when you can just upgrade and have it available so you don't have to shed...especially when the installed noisemaker can supply it all too!

i have a 50 amp240 splitter that goes from 240 to 2 50 amp 110s for sale if any body is intrested. i also have a 50amp 240 plug that comes out to 30 amps 110 it is a single plug, you plug it in to 240 but get 110 out of it,and a bunch oe other adapters

Upgrading the dock service is always easy. If there is but 120 volt service there than replacing the breaker with a 50 amp breaker will permit a highter load, if you can find a way to split the load, but not as good as a 220volt dock service and than the larger breaker and a 50 amp to 30 amp Y would permit normal loads on the 120, 30 amp cables.

jwnall said:

Maybe I'm missing something here. The marina where I (will) keep the boat only offers 30 amp receptacles. So how can I upgrade?

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In your original post, you state:

I figure that in a marina I will most likely find either one 30-amp receptacle or one 50-amp receptacle.

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If you want an answer you can use, you have you ask the right question. Otherwise you will get wrong answers or off topic answers. So -

Are you looking for a solution for a specific marina or a solution for transient marinas where you may stay for a day, week, etc.?

Answer that, and you're more likely to get advice that you can use.

Hey John,

Be careful if you plug both cords into one 30 amp outlet, the aft air conditioner draws a lot of juice on start up, which is why I had a dedicated cord set up for it alone. If you are going to run that aft ac, it really should have its own dedicated 30 amp outlet, or 1/2 of a 50 amp.

The boat is currently plugged in to a single 50 amp that is split into the 2 30's. I left you the 50 to 2 30's splitter,

My guess is that St. Marks will have 2 30 amp outlets available for you.

Doug

Thanks, Doug. That is good to know, and thanks for leaving the 50-to-30 adapter on there. If St. Marks does not have two outlets I will see if I can pay to have another one put in, since I plan to be there a long time.

John