Power cord burnt ?

The wife and I decided to enjoy the beautiful day on Galveston Bay. Every thing electric, 110 and 12v had been working fine without an indication of trouble. The generator started without issue as always. I went out to disconnect the shore power, shut of the breaker at the box and tried to remove the cord from the boat. It was stuck. Had to wiggle and use a lot of twisting pressure only to find that the female plug was burnt and melted and the male plug was also damaged. Upon return, I cleaned the fitting and cord and plugged it back in to find everything working fine. The cord is 50amp rated.

My question is, what caused this and how worried should I be about my electrical systems. I've checked everything and all systems are reading fine.

Thanks for your feedback. Jk

Make sure to check the plug on the boat side. Mine was corroded and burned/slightly melted. My surveyor said this is one of the number one reasons for boat fires
It's because people leave the shore power on when disconnecting and they actually cause a little short/spark which over time causes higher resistance in the plug. This causes a fire Rusk over time. All I can say is I pulled the old plug and it was black near one prong. So now I always turn off the boat and shore power prior to disconnection. Are you running high draw appliances such as heaters? These tax our boats electrical that's when you should monitor your plugs for heat = resistance

"this is one of the number one reasons for boat fires"

I have seen this happen.
Throw out the burned unit, both the female end on your cord and the male end on your boat.

You might try the newer "smart plug" as a replacement that is unlikely to suffer the same fate. When I switched mine over to a "Smart plug" my insurance Co sent me a cheque for $125.00 on a $185. cost to convert. I had to send a digital photo to show the installation was complete.

Like these? The cause most likely was corrosion over time on either the male or female part of the plug/socket. This causes resistance which heats up the plug/socket which melts the plastic. Inspect/clean monthly and use a contact cleaner. CRC makes a good one. 03070 -- Contact Cleaner, 14 Wt Oz

Jk, another possible contributing factor could be the plug getting knocked around on the boat end- depending on the location of the boat receptacle. On our Sundeck, we had problems with "arcing" and this led to more resistance at the plug, higher amps at the AC compressor, etc, etc.. Our two 30 amp cords plug in midship, just above the stbd walkway. Since repairing I have gotten in the habit of looping both cords around the nearby stanchion and security with a WM Velcro strap (love those things!). I also try to position the boat with a port entry whenever possible, reducing foot traffic near the area.

Knot-Enuff said:

The wife and I decided to enjoy the beautiful day on Galveston Bay. Every thing electric, 110 and 12v had been working fine without an indication of trouble. The generator started without issue as always. I went out to disconnect the shore power, shut of the breaker at the box and tried to remove the cord from the boat. It was stuck. Had to wiggle and use a lot of twisting pressure only to find that the female plug was burnt and melted and the male plug was also damaged. Upon return, I cleaned the fitting and cord and plugged it back in to find everything working fine. The cord is 50amp rated.

My question is, what caused this and how worried should I be about my electrical systems. I've checked everything and all systems are reading fine.

Thanks for your feedback. Jk

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Like the reasons mentioned there could be a couple more suspects. A loose connection will cause that to happen, does it fit tight when plugging in? The other one might be dislimmer metals in your cord and shore inlet connection which will cause corrosion.

Elwin

Sent from my SGH-I337M using Trawler

I second a SmartPlug, easy swap with way better locking, weatherproof and thermal protection........

rochepoint said:

I second a SmartPlug, easy swap with way better locking, weatherproof and thermal protection........

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Me thrice...

SmartPlugs are pretty smart...

Before they rebuilt our marina, I would go through a dockside plug and socket every couple of years. Our docks were 35+ years old and the electrical boxes on the dock stanchions were not protected from the elements. Once they rebuilt the marina and installed modern weather resistant stanchions, my plug end and socket looks like new.

Also if your power cord dock end is bad, showing signs of arching, melting, corrosion, be sure to ask the marina to change out the socket on the dock stanchion before you install a new plug or power cord. Plugging a new cord into a damage socket will result in failure.

koliver said:

Throw out the burned unit, both the female end on your cord and the male end on your boat.

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What he said ...

Same thing happened to me. Went right to West Marine and replaced the boat receptacle and they gave me a new cord to replace the bad one. They just cut off the bad female end as proof for Marinco and gave me the original cord back, too.

Of course, if you're switching to the SmartPlug, that might not work out for you.

Knot Enough,
Same thing happened to us a while back. Turned out it was corrosion where the wire meets the input receptacle on the boat. Had to replace short runs to the breakers on the boat. Probably could have got by with cutting back and recrimping. Good luck.

The key thing is to look carefully at all ends of the terminations, the shore power to the pedestal, pedestal receptacle , shore end of your power cord, boat end of the cord, boat receptacle, wires to receptacle, and the wire ends at the shore power breaker on the boat.
All of it is a pain in the butt.. it needs to be done as I have seen the shore power circuit show overload signs at other points in the system because of a fault at another point.
Also as someone else also pointed out always shut off the power at the pedestal first to insure no arcing occurs.

This the season for boats to catch fire..
HOLLYWOOD

I have a 1981 49' Grand Banks. It had one 50 Amp-120VAC and one 50 Amp 120/240VAC plug in both fore and aft. I removed both and replaced with SMART PLUG units, both 30 Amp 120VAC. I think their system is well engineered. I like the locking system and overheat protection. I have seen many boat owners just pull the power cable from the dock box having never shut off the AC input on their vessel or CBs on the dock box power supply. If you did this at night you would notice a spark, flash of energy jumping the contacts. Best procedure is to turn off AC items with in your vessel first then CBs on the dock box, then unplug and stow your power cable. Too many power cables have been dropped in the water with power on. Not a great way to test the dock box C/Bs. Coming in to dock put plug in to both your vessel and to dock box, turn on dock box CBs then turn on items you wish to power with in your vessel.
When you come to your vessel after being away, walk up to the dock box power suppy and wrap your hand around the end of cable. It should not be warm or HOT. Board you vessel and do the same at the power inlet on your boat. It should be ambient temperature also. This also holds true for any electrical heaters you may place on board. The insurance companies love to VOID policies when a vessel has a fire caused by a cheap electrical heater with no safe guards. KING heaters out of Seattle, are one of the few companies making heaters meeting marine safety needs. It is not good luck but good prevention that will keep your vessel safe.

Moonfish said:

SmartPlugs are pretty smart...

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I switched a couple of years ago.

Thanks for all of your comments. We'll taken and I just ordered my Smart Plug conversion kit from Defender Marine. ( best price I could find ). Jk

Walt did you cut the Marinco cables and fit the Smart plugs to the existing cable or buy coplete new cable with ends already made up?

Had the Smart Plug system on our last boat- I just cut the existing cable ends off and installed the Smart Plug.

Steve said:

Walt did you cut the Marinco cables and fit the Smart plugs to the existing cable or buy coplete new cable with ends already made up?

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Actually, I did both! I bought the receptacle for the boat and its female mate for the cord. (leaving the old dock connection in tact.) Then, because we overnight once in awhile with an old friend at Coronado Island, I bought a complete assy (cord and all) for marina hopping & it's stored on the boat.. (My slip cord is fastened to the dock and is to cumbersome to remove and take with me.)

The fact that the Smart Plug has a thermostat that shuts off all power to the boat , should a problem occur, is really comforting.

I put grease, the electrician stuff, on mine and I don't get sparks. Works great at a fraction of the cost of a smart plug.

Knot-Enuff said:

Thanks for all of your comments. We'll taken and I just ordered my Smart Plug conversion kit from Defender Marine. ( best price I could find ). Jk

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I got good prices at Shore Power Cords - Marine Electrical Connectors - Smart Plug Only

I have the smart plug system, changed over a couple of years ago and I'am very happy with them. Even with the thermal protection I still periodically check the temp of the connection with my ir temp gun, any loose connection can cause resistance and that = heat. I also check the screws on the rotary switch & circuit breakers for tightness once a year, a fire on the boat scares me & proper care of the electric system can prevent it.

Marinco shore-power cables and receptacles have a couple of safety features built in:

1. When the male plug is fully inserted, turn it slightly clockwise and it locks in place - pull gently to check that it has.

2. Threaded sealing collars are available in 30 and 50 amp. There is also a threaded sleeve (arrow) for use when joining two cables together. The collar only takes a moment to tighten, seals out the weather and prevents accidental disconnection. I think the pics speak for themselves.

Twist &turn power cables were introduced about 1938. A lot of water has gone over the dam since then in power cable design.

Capthead said:

I put grease, the electrician stuff, on mine and I don't get sparks. Works great at a fraction of the cost of a smart plug.

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SmartPlug is a lot better and when your insurance company pays for most of the cost........they think it is a better solution..........

Shoalwaters said:

Marinco shore-power cables and receptacles have a couple of safety features built in:

1. When the male plug is fully inserted, turn it slightly clockwise and it locks in place - pull gently to check that it has.

2. Threaded sealing collars are available in 30 and 50 amp. There is also a threaded sleeve (arrow) for use when joining two cables together. The collar only takes a moment to tighten, seals out the weather and prevents accidental disconnection. I think the pics speak for themselves.

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I have the same molded plug like yours, only my locking ring is chromed metal with gasket? I don't unplug mine from the boat very often and this was a good reminder and time to check it anyway. Gasket and contacts were in good shape and I think I will keep it a while longer.

SeaHorse II said:

Twist &turn power cables were introduced about 1938.

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Are you operating from memory here, Walt?

Walt, you don't need to put up with this stuff, hit em with your cane!

One ez burnout is from short term overload,a 30A cord will run 2 air cond , but every time the second unit starts the cord will be way above its limit.

The Circuit breaker has delay features to stop nuisance trips , so the overload does not pop the breaker.