30 Amp Cord?

[Osprey69]

Finally closed (another story) on a Gulfstar 49. We do not have a 30 amp shore power cord. Do we really need one given modern dock systems?

Thanks in advance.

 

[Comodave]

What power cord do you have? If you have a 50 then you will need an adapter to be able to plug into 30 amp outlets which are the most prevalent. Some marinas will only have 30.

 

[Osprey69]

Have a 50. So my assumption of a marina handling a 50' boat also has 50 amp is incorrect?

Thanks.

 

[O C Diver]

Have a 50. So my assumption of a marina handling a 50' boat also has 50 amp is incorrect?

Thanks.

Most newer marinas will 50 amp service for 50' slips. Some older marinas may only have two 30 amp receptacles. Having an adapter to combine to 30s to your 50 amp cord could be beneficial. Then again, you could judge need based on experience with where you cruise.

Ted

 

[Flatswing]

Presumably you have a 50A 125/250 v cord & boat since 50A 125v boats (& Marina receptacles) are much less common. Google 30A & 50 A cords & u will see both have 3 prongs BUT: the 30 A has only hot, neutral & ground; whereas the 50A has hot-L1, hot-L2, neutral , with the ground being the outside of the plug/inside of the receptacle.
Most marinas that can handle your boat will have 50A/125/250 receptacles - at least on the East USA Coast. In Canada on the loop & very small facilities, you may need a smart “Y” that allows 2 x 30A receptacles to connect to your 50A cord. I will only get 30A total in this situation so may need to manage your power requirements.
The caveat is: each 30 A must be on a different leg (L1& L2) to work.
I have 2 for some reason & can sell u one cheap if u r close to SC.
Another caveat: smart “Y”s will not work at marinas which have upgraded their electrical system & have the new & very sensitive ELCI’s (‘cus the neutral is returning on both legs and the ELCI’s can detect any difference). Fortunately, if they are that new, they almost always have 50 A 125/250v service.

Enjoy your new boat!

 

[FF]

"I have 2 for some reason & can sell u one cheap if u r close to SC."

This dumb style Y can work if you check the power first.

If you stick the probes into the socket and read 240V between the hot legs your'e fine.

What you do not want to bring aboard is (2) 120v that are the same red or black leg.

 

[O C Diver]

The smart Y shore power adapters don't work on 30 amp shore power receptacles that are powered by 208 volt transformers. They work fine on 220 and 240 volt transformers.

Ted

 

[rslifkin]

"I have 2 for some reason & can sell u one cheap if u r close to SC."

This dumb style Y can work if you check the power first.

If you stick the probes into the socket and read 240V between the hot legs your'e fine.

What you do not want to bring aboard is (2) 120v that are the same red or black leg.

This depends on how the boat is wired. The 6ga neutral in a 50A cord can handle 60 amps safely (although I'd be careful to keep the total down to 50A for sake of the connectors). If there are 240v loads on board, then 2x 120v in phase won't power those. If there aren't, then it won't matter, as both sides of the panel will still see 120v each and everything will run fine.

 

[Osprey69]

Thanks to all. Found the 2 30 amp to one 50 amp Y adaptor buried in a locker.

On a thread creep note, we put a galvanic isolator in the system to adapt to the newer sensitive shore power systems that we were tripping.

 

[Flatswing]

“On a thread creep note, we put a galvanic isolator in the system to adapt to the newer sensitive shore power systems that we were tripping.”
Pretty sure that would be an uncommon fix. An isolation transformer would prevent ELCI tripping. But still better is to trouble shoot your AC neutrals if you have an inverter or non marine appliances. Basic rule:the AC neutral should return all the “hot” current & should only be grounded at the source.
Many boats with inverters have the inverter circuits’ AC neutrals commingled with the non inverter circuits (even the panel LED’s can be the culprit). Some appliances for shore use have the AC neutral bonded to ground. Everything works until you plug into a new Marina & trip the new & more sensitive ELCI.
A galvanic isolator elevates the threshold of the returning current but doesn’t fix the AC neutral path issue.

 

[Comodave]

“On a thread creep note, we put a galvanic isolator in the system to adapt to the newer sensitive shore power systems that we were tripping.”
Pretty sure that would be an uncommon fix. An isolation transformer would prevent ELCI tripping. But still better is to trouble shoot your AC neutrals if you have an inverter or non marine appliances. Basic rule:the AC neutral should return all the “hot” current & should only be grounded at the source.
Many boats with inverters have the inverter circuits’ AC neutrals commingled with the non inverter circuits (even the panel LED’s can be the culprit). Some appliances for shore use have the AC neutral bonded to ground. Everything works until you plug into a new Marina & trip the new & more sensitive ELCI.
A galvanic isolator elevates the threshold of the returning current but doesn’t fix the AC neutral path issue.

+1.

 

[O C Diver]

On a thread creep note, we put a galvanic isolator in the system to adapt to the newer sensitive shore power systems that we were tripping.

An isolation transformer would do that. Don't know if that was what you were referring to.

Ted

 

[Osprey69]

When I get back to the boat I will (hopefully) correct myself.

 

[timb7734]

In Florida/Bahamas there is usually 50 amp 240 v readily available.

In the Great Lakes not enough is available and there I would carry a smart Y and a couple 30 cables 50’ long.

 

[Osprey69]

Thanks for the replies. All set.