30A Service

[Photolomy]

Remember when we were talking about 30A service and how we didn't need it? Well, in the yard that is all they have, and so I bought a single 50ft 30A cord, cause my chargers are only on one side. Anyways, it plugged into the yard outlet ok, but what I thought were 30A/125v outlets on the boat are actually 50A/125v outlets, not 30A/125v outlets, and they are labeled as such. The difference is that the 50A/125v haa one prong with a tab that goes down, while the 30A/125v version has a tab that goes up, and the three prongs are wired differently. My guess is that Hatteras did it so that you could use a 50A/250v cord and then some sort of 50A to 30A adapter on the dock side. I know that you can use a Y and connect 2 30A/125v out-of-phase dock connections, but that adapter is like $400. What I did was to cut off the female end of the 30A/125v cord I bought ($94) and added a female 50A/125v plug ($100) to match the boat. The 50A (female) to 30A (male) adapter would have been cheaper, but I needed to get it power today.

Here is a chart that shows the various types of outlets...



The bottom one is what we are used to for 50A/250v. The middle one is a standard 30A/125v cord, which is what I bought. The 4th one is what the 30A plugs on the boat are, 50A/125v. Note that the L shaped prong is opposite that of a 30A/125v plug, and the wiring is different.

This is the adapter you would use with a standard 30A cord...

https://www.amazon.com/Marinco-electrical-pigtail-adapter-121A/dp/B000NI1BGG/ref=sr_1_5?dchild=1&keywords=marine%2B50%2Bamp%2Bto%2B30%2Bamp%2Badapter&qid=1625349702&sr=8-5&th=1

As I said, I needed power now and the marina store had a 50A/125v plug available. I did not try plugging my 50A/250v cord into the 50A/125v boat outlet, but it looks like it would fit. But then you would need a 30A/125 to 50A/250v adapter AND it would have to be wired for 125v.

Maybe this one? ...

https://www.amazon.com/Marinco-electrical-pigtail-adapter-121A/dp/B000NI58ZG/ref=sr_1_5?dchild=1&keywords=marine%2B50%2Bamp%2Bto%2B30%2Bamp%2Badapter&qid=1625349702&sr=8-5&th=1

Of course, this would only power one leg (S1 or S2), you would have to repeat it for the second leg, and as Oscar found out, that won't give you 220v at all.

The other solution is to use a 30A Y that takes two out-of-phase 30A outlets and combines them into one 30A/250v outlet with a 50A/250v plug. The problem with that is that the two 30A outlets must be out-of-phase, or you will get nothing. And they are expensive.

Anyways, amps and voltage determines the plug configuration, and Hatteras didn't help much by putting odd 50A/125v male outlets for S1 and S2.

 

[oscarvan]

We were talking about the 125V/50A service and how we didn't need it. And, my 125V connections are 50A and labeled such, not 30A. Someone post Hatteras messed with yours. And for the record I didn't find out......that two 110's wouldn't give me 220. I knew that. My question was whether there was a path from the 125V selectors to the 220V selector. I didn't want there to be one. Different ball of kittens.

 

[Photolomy]

We were talking about the 125V/50A service and how we didn't need it. And, my 125V connections are 50A and labeled such, not 30A. Someone post Hatteras messed with yours. And for the record I didn't find out......that two 110's wouldn't give me 220. I knew that. My question was whether there was a path from the 125V selectors to the 220V selector. I didn't want there to be one. Different ball of kittens.

Sorry, it may actually be labeled 50/125v, but the main point is that is a very odd plug configuration that as far as I know, doesn't exist at any dock. You will find 30A/125v, but the plugs are different. Thus, if you ever do have to use a 30A shore outley, you will have to make the cord, or buy adapters. A straight 30A cord will not cut it. Even a 50A/125v will not cut it, cause it will match the boat, but not the pedestal.

I am not sure how you would know that you can't use two 110's and get 220, as this is such a common practice. In fact, you can buy a reverse Y adapter that does exactly that for your 50A/250v, as long as the two 30A/125v are out of phase. I am not sure why Hatteras decided to not support it in their switching panel. Maybe they were worried that someone would plug in two 30A of the same phase, and they did not incorporate safeguards for that (that are incorporated in reverse Y cables). Maybe boats with iso transformers are more capable and do support the combination of two 30A cords? If you go back in these forums, the assumption was that the switching panel supported it, and I am glad that you dug through the panel and realized it doesn't. There were a lot of plans to provide 220v via two stacked inverters feeding S1 and S2. Those plans are kaput now.

Edit: I understand now why you didn't want a path, because you connected a single inverter to both S1 and S2, which would short if there was a path and say, you turned on the 220v stove.

 

[Photolomy]

Buy the adapter or or modify an existing cable.
I'm not sure I understand your complication.

I modified the cable. It was in my post. I was pressed for time, otherwise I would have found and purchased an adapter. Ideally, a 50A/250v to 30A/125v, and could just use my normal 50A cord in those rare circumstances (such as with this boat yard) that I needed to connect to 30A125v service. I was just pointing out that you will need to do either if you need to connect to 30A/125 service. I guess in the day, 50A/125v service was a thing. Today it isn't. There is 50A/250v and 30A/125v.

 

[oscarvan]

I have the adapter.