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**GordMay** · 03-12-2007, 12:18

David makes a good point about "securing" un-used wire ends.
I usually fill the end of the but splice /w silicone (one of the few uses I make of R2SiO), and install a clear heat shrink over it & the label (we do label ALL wires, don't we?).
If you're going to "pinch off" the end, make certain the sleeve insulator is Nylon (NOT Vinyl).
In the pictured female connector (boat side), the problem (& fatalities) resulted from the miss- connection of the ungrounded AC "Hot" supply wire, to the boat's ground, not from the unconnected ground conductor.

jro3330 · 28-07-2017, 16:35

Corrosion was evident in Dilbert's brain when he rewired my boat for the previous owner. He ran #12 wire from the circuit breaker to the shore power connection on the boat.

Captain Bill · 28-07-2017, 18:52

I recently fried a power cord and the boat side receptacle I replaced the cord end with a marine grade replacement for about half the price of a new cord. I also replaced the boat receptacle and while doing so found the source of my problem. The wire was corroded for 6" back from the rear of the receptacle on both the hot and neutral wires. The ground wire was fine. I cut back until I hit clean wire and connected the new receptacle and all is now fine. Fortunately the builder left enough slack in the wire that I could do this. For those of you who might wonder, yes this was tinned marine grade wire 8 awg. It was carrying less than 15 amps when it failed, though obviously it had been heading towards failure for a long time.

For the OP recognize that the root cause of your burned plug may not be in the power cord but in your boat side wiring. Putting a new end on your power cord may just result in another burned socket.

rwidman · 29-07-2017, 09:00

Quote:

Originally Posted by senormechanico

"It should be impossible to “put too many Amps through” (overload) the shore power circuit."

Gord,
You obviously haven't landed at Marina Nuevo Vallarta in Puerto Vallarta. Maybe they've fixed it since I cruised in the '90's, but back then it was a cheap seat marina where lots of broken dreams sailors ended up.

The wiring was a live bare wire do it yourself affair as was how you moored.

To get shorepower, you gingerly found out which wire was the hot one
(Color coding? wee don' need no steenkin' color coding!) then you attached your own system of connecting your shorepower cord to it. Some people used alligator clip leads!

Lots of 20' finger piers with not a lot of boats so people tied diagonally in 2 slips, or across the ends of 3 fingers etc.

As you may imagine, there were boats piled high with junk on the decks and there was a swap meet every day. As you may also imagine, there were almost no women in the marina.

Steve B.

Even if the marina's electrical system isn't up to code, your boat has a current limiting circuit breaker. So, for example, with a 30 amp breaker on the boat, no more than 30 amps will flow through your shore power cord before the breaker trips.

I doubt you'll find many (or any) non-compliant marinas in the USA.

The dock end or a shore power cord can be damaged by a defective or loose receptacle on the dock. You don't have much control over this unless you own the dock.

rwidman · 29-07-2017, 09:15

Quote:

Originally Posted by Dream Maker

Is it safe or recommended to replace a three prong end of a 30 amp power cord with a replacement. It seems quite wasteful to throw away a whole 50 foot power cord because of a scorched end. I found a replacement Turnlock Locking Plug at Lowe’s. It is 30 amp 125 VAC. It doesn’t say marine grade or water proof but the fellow at the store said it would be fine. I haven’t seen anything from Marinco at West Marine.

It is safe to replace the end of a 30 amp power cord, but I can't guarantee it is safe for you to replace it. You have to connect the correct wire to each terminal, they are not interchangeable.

I doubt the guy at Lowes knows about marine wiring and I doubt that anything you find at Lowes is a suitable replacement for your plug.

I'm also pretty surprised that you can't find Marinco parts at West Marine. Did you ask?

Marinco isn't the only brand of marine plugs and sockets but it's critical that you use a "marine" replacement plug and it's critical that you connect the wires correctly and follow the instructions. If there's any doubt about your ability to do this, either get some competent help or just buy a new cord instead of trying to replace the end.

zeehag · 29-07-2017, 09:41

i have seen that kind of burn when the twist lock fail occurs, which is generally installation issue--the installer of plug into socket failed to twist it locked, which affects proper ground. with ground fail you will see the burned plug occur. the twist lock is to complete the ground.
and yes it is ok to replace the plug safely . i would use a weather proof cover.
ps btdt...when my repair crew failed to twist the plug locked into socket. oopsy. now i use a back up device to check ground and polarity..is a special surge protector with the check lights in place. i use 2 of em. when twist lock is not accomplished, the light is off. with completed ground, both lights are lit. love it. has saved my stuff more than once since i bought it in 2011

Seabeau · 29-07-2017, 10:10

I replaced the female end of my 30 amp cord and boat receptacle with a new "Smart Plug" retrofit kit. Highly safer design, than the almost 70 year old construction industry adapted marine twist-lock plugs.

rwidman · 29-07-2017, 10:19

Quote:

Originally Posted by zeehag

i have seen that kind of burn when the twist lock fail occurs, which is generally installation issue--the installer of plug into socket failed to twist it locked, which affects proper ground. with ground fail you will see the burned plug occur. the twist lock is to complete the ground. ..........................

Nope, while not having a proper ground is definitely unsafe and should be avoided, it will not burn the plug. There should be no current flowing in the ground conductor.. Current flows through the hot and neutral conductors only, unless there is a fault. The ground circuit is for safety only.

The twist lock feature is just to keep the plug from falling out.

Hint: Before inserting the plug, give the cord a reverse twist, then plug it in and twist. This twist will help the plug stay in place.

DeepFrz · 29-07-2017, 10:32

Thanks for resurrecting a 10 yr. old thread. I was wondering why there was little mention of the smart plug. Take Seabeau's suggestion and convert to a smart plug. Much less chance of a fire.

Houston450 · 30-07-2017, 10:59

Quote:

Originally Posted by DeepFrz

Thanks for resurrecting a 10 yr. old thread. I was wondering why there was little mention of the smart plug. Take Seabeau's suggestion and convert to a smart plug. Much less chance of a fire.

I have a similar problem with a slight twist. My shore side plug shows signs of burning and based on the recommendation here I will convert to smart plug.

My issue is on my Lagoon 450. It has 2 switches in the panel for shore side and generator power. One seems for battery charger and the other for air conditioning. The air conditioning will not come on when hooked to shore power. The batter charger does. Both work fine on generator power.

I swapped cords to our long spare which does not show signs of burning and no improvement.

Is there a breaker that may have tripped?

Chris
Lagoon 450 #394

boatbod · 30-07-2017, 16:43

Lagoon has shore main breakers inside a cabinet - port hull, aft cabin, if I recall correctly.

DeepFrz · 30-07-2017, 16:52

The shore power connection on the boat is one of the main fire combustion points. That is why the smart plug is so important. If your connector is already damaged it may have a high enough resistance that the air con. wont come on. It that is the case you are in danger of setting your boat on fire.

ValiantV · 30-07-2017, 17:19

Quote:

Originally Posted by DeepFrz

Thanks for resurrecting a 10 yr. old thread. I was wondering why there was little mention of the smart plug. Take Seabeau's suggestion and convert to a smart plug. Much less chance of a fire.

I replaced our boat end of the cord with a SmartPlug and receptical, but unless you own the marina, you're stuck with the twist lock on the dock end.

Be careful to get the yellow "moisture resistant" ("marine") grade plug as the standard shop grade may not like the dampness. The yellow ones are less common and thus (sigh) cost quite a bit more.