Houseboat 3 prong to 110 conversion

Doc

Liquid Addiction
Staff member
I'm looking for a simple little plug to convert from my houseboat big thick yellow wire down to male 110 prongs. I thought it would be easy to find but the RV shops don't have it. Neither does Lowes or Home Depot.
I have 25' of cord from the houseboat but would like to get a 50 footer. I'm afraid that would cost a fortune. My 25 foot one reachs the power box on our regular docking spot. The place we visit on weekends is where I need the 3 prong with L to convert to 3 prong 110.
Does anyone know what I'm talking about & where I can buy a couple adapters?
 

OhioTC18

New member
Doc,
It's possible to make one up by using a 50' extension cord and putting the proper cord cap on the end. I'd need to know exactly what end you need. Voltage? Amps? Even the Nema configuration number if possible on your 25' cord.
 

Doc

Liquid Addiction
Staff member
Thanks guys.
Jerry, I can try to find out exactly what I need, but right now I'm not sure.
My bro had a simple female 3 prong that fit my boat cord with a 3 prong 110 outlet on the other side. It came with the boat he bought this year from an engineer. No idea where he got it.

As I understand it we now have 30amps at the dock for power. My boat takes two of those plugs. The breakers we switch off before plugging or unplugging are the basic 15 amp size so I presumed we had 15 amps per cord. :confused:
Maybe they do handle 30 amps each. But why would you reduce amperage for a pigtail conversion plug? If I'm pluggin into a source with 15amps only, doesn't that effectivally reduce the amperage?
Is there a chance of hurting equipment by running on to low of amperage or to low of voltage?
 

OhioTC18

New member
I just needed to know to look for the right cord cap for you.

If your supply is only 15 Amps, you're never going to get more than that. You just can't run all of your electrical items.
 

Doc

Liquid Addiction
Staff member
What kind of place would carry the 'cord cap' Jerry? I looked at Lowes, a RV store, A boat store and I'm out of ideas. There is an industrial type of supply place that sells most things electrical. maybe they would have it.
What makes these things so expensive. I don't understand why converting 3 prongs of one type to a standard house plug would cost so friggin much?
If I can find the right ends would it be stupid to make my own? What could I hurt doing it that way?
 

OhioTC18

New member
Making your own might be the way to go. Buy an ordinary 25-50' cord with the 3 prong 110 Volt plug on one end and swap out the the other end with the right match for your present 25' cord.

If it's a NEMA L5-30 my local Lowes might have it. If it's a NEMA 14-30 (which I doubt) it may have to picked up at a supply house. Here is a link to an L14-30 cord cap. You would just have to use 3 of the 4 terminals in the cord cap.
Here is a link to an L5-30 cord cap at Lowes (which is probably what it is). You just didn't think outside the box. Buy an extension cord and the cord end and be done with it. Remember if it's sold for a boat or a tractor, it's more expensive. BT Doctur might be able to find out if it's an L5-30 or not.


edit.............look at the end of the plug on the present cord or the outlet it plugs into for shore power. One or both should be marked with the NEMA configuration number.
 
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Doc

Liquid Addiction
Staff member
Thanks Jerry. You nailed it. :D

I will check that NEMA number but I suspect you are right on with the L5-30. It looks just like it.

What gauge extension cord would be best with that? 14ga seems light duty compared to the cord coming off my boat.
 

OhioTC18

New member
Keep in mind you're probably plugging into a 15A outlet. 25' of 14 AWG is fine. If you go to 50' go with 12 AWG.

The cord you have is rated for 30A. It will be bigger. It also is a different insulation for marine applications. But you're only going to use it for a weekend here and there for a tie up.
 

waybomb

I'd rather be blown
Doc

Get the marine grade thing. Be Safe. Go to ebay. You'll find the correct one. And a bunch cheaper.

I bought all my adapters on ebay when we had the 42 Carver. It had two 50 amp 110v inlets. I have a giant Marinco bag full of about 70 pounds of various adapters with cords. Different marinas and even different slips have all sorts of configurations.
 

Doc

Liquid Addiction
Staff member
Good thought Fred. I found one on ebay. It's at 20 bucks now. We'll see where it gets to by tomorrow at close of auction. Thanks.

I'm still going to make up a 25ft extension with the right ends though for one special place that we like to dock. :D
 

Doc

Liquid Addiction
Staff member
Jerry, I picked up a couple end caps (guess that is what they are called) and 25' of 12 gauge extention cord. I put the ground (green wire) to the L shapped inlet since it had a green screw. Then I hooked the white and black to other two connections. Before I do the 2nd one ... that is the correct way to wire this, right?
 

Bamby

New member
Doc you're going to have to open your fuse box and look at the current wiring on your boat. With your current cord what you've effectively have is probably a 30 amp service consisting of two 15 amp 120 circuits usually one red and one black wire plus common ground. Hopefully your boat will be split at fuse box one circuit feeding air conditioner and the other feeding all other 120 volt circuits. With your conversion you're only going to feed one side usually all your appliances. Use the black 120 wire and wire it to the side of plug that feeds the circuit you want power to. The green and white wires are really in any real since both grounds and the second hot side of your boat plug is not used.
 

Doc

Liquid Addiction
Staff member
utt oh. I went ahead and did the 2nd one. I thought with A/C the white and the black are more or less interchangable. The ground / green wire has to go to the ground which I 'think' is the differently shaped plug (it's L shapped and the other two are blades.
The two power cords are 30 amp, 15 on each. Front and rear air conditioners so one is on each circut with outlets and other stuff divided between them.
 

Bamby

New member
I was kind of afraid of that. I know how many of the houseboats at our marina are an electrical nightmare of jury-rigging from past and present owners. In a 110 outlet circuit depending on who wired it with what gauge wire you'll ether have 15 amps or at most 20 amps available. Unless somebody screwed up the white wire carries nothing, all the available current is carried by the black wire. So if even you were to run two separate extension cords to an outlet and wire them to your boat you're still only going to have at most 20 amps available and when two many appliances try to start you're going to blow fuses or trip breakers in their garage or wherever. Doc you probably really should have an electrician look this all over to be safe. It can be done but you'll probably have to take the air conditioners out of the picture for this to work on a 110 20 amp. service.
 
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Doc

Liquid Addiction
Staff member
Thanks guys. Understood the air will not work on the lower amperage circuts. I'm just afer the fridg and the battery charger and both are on different circuts, so I need two cords.
The end caps I got were not color coded for the black and white wires. :bonk:
 
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