Will my boat catch fire?

[St. Elsewhere]

Originally Posted by Windseeker

Do you think the burnt female shore power cable connector can be replaced? I THINK the cord I have is a solid molded piece (i.e., not serviceable). I believe I would have to cut it off to attach a new one. Would a replacement have the same integrity?

You do need to cut it off. The new one will have a back shell clamp that will hold the wire securely. If your wire is too small diameter, wrap it with electrical tape to make it larger to get the clam to work effectively.

Also, your pictures do not show visible signs of arcing. If arcing has occurred, there will be blackened rough areas in the metal. If you are experience arcing due to movement of the connection, you will need the silicone grease.

[delmarrey]

Here is the Hubbell catalog. Hubbell Marine 2008 Catalog

You'll need both connectors! Once the plastic is cooked they need replacing. Choose what you need from the catalog and then goto ebay and type in the part #. You'll find them for a lot less there. e.g. HBL26CM13 | eBay

[CarlF]

All good advice.

I'd second Waterwayguy's comment. The whole US marine outlet system is poorly designed for today's usage. Until you have turned the plug, the contacts are not fully mated and arcing is likely to occur inside the outlet. With normal corrosion on the marina power outlets - especially the 50 amp ones - it can be very hard to turn the plug.

I'm sure that when the system first came into use, professional crew or dock hands always handled the cords. Today, it's often a boat owner with little understanding of electrical systems or the fire hazards. My guess is that many boaters don't even know that the turn is required.

Carl

[Jim Cate]

While I am agreed that greasing connectors is a good idea in general, I don't understand the use of a "dielectric" grease. Dielectric means non-conductive. There are, however, conductive greases which should do the job much better while helping repel water and lubricating mechanical connections.

Jim

[St. Elsewhere]

Originally Posted by Jim Cate

While I am agreed that greasing connectors is a good idea in general, I don't understand the use of a "dielectric" grease. Dielectric means non-conductive. There are, however, conductive greases which should do the job much better while helping repel water and lubricating mechanical connections.

Jim

Jim,

The objective of diaelectric grease is to achieve conductivitly via the metal-to-metal contacts, not through the grease. The prupose of the grease is to prevent corrosion of the metal which results in hot metal-to-metal contacts under load. Conductive grease could allow a current path from hot-to-neutral, and from hot-to-ground. This would mean really bad news. In general, you never want conductive grease in such ciruits. Current going to ground would put stray current in the water which coud be leathal to anyone in the water. Current going to neutral could produce heat and cause ignition.

[Jim Cate]

Originally Posted by St. Elsewhere

Jim,

The objective of diaelectric grease is to achieve conductivitly via the metal-to-metal contacts, not through the grease. The prupose of the grease is to prevent corrosion of the metal which results in hot metal-to-metal contacts under load. Conductive grease could allow a current path from hot-to-neutral, and from hot-to-ground. This would mean really bad news. In general, you never want conductive grease in such ciruits. Current going to ground would put stray current in the water which coud be leathal to anyone in the water. Current going to neutral could produce heat and cause ignition.

Ahh, yes, point taken! I Retract the recommendation for conductive grease in this application.

Cheers,

Jim

[motion30]

You need to secure the cord with a rope or a tie down of some kind maybe 2' from the plug This will keep from working your plug Yes you car replace the end but check prices, sometimes the whole cord is cheaper

[GordMay]

Originally Posted by Jim Cate

While I am agreed that greasing connectors is a good idea in general, I don't understand the use of a "dielectric" grease. Dielectric means non-conductive. There are, however, conductive greases which should do the job much better while helping repel water and lubricating mechanical connections.
Jim

Indeed.
Dielectric grease is used to seal the rubber mating surfaces, not the electrical contacts.

[Pete7]

Windseeker, interesting thread . We too had the same problem end of last year. I had assumed it was the male and female connectors which had finally worn out leading to arcing. Ours are Euro ones so slightly different (cheaper) but same problem and we use a Honda 20i as well.

New plug and socket seems to have cured the problem.

Pete

[CharlieJ]

Windseeker-Yes you can replace the molded on end of the cable. Simply cut off the failed end and prepare the conductors, Whether you replace the failed end with Marinco, Hubbell or SmartPlug, ensure that you follow the instruction sheet to the letter.

Charlie

[osirissail]

Originally Posted by GordMay

Indeed.
Dielectric grease is used to seal the rubber mating surfaces, not the electrical contacts.

Not quite - - Dielectric grease is as Jim Cates explained used to keep salt water corrosion off the metal parts of the plug/receptacle. "Sealing" means a more permanent closure to prevent ingress of something - like moisture/water. Few if any common shore power cords have "rubber mating surfaces/lips that shield the actual plug from water/rain splash.
- - As others have mentioned worn out female metal contacts inside a receptacle can allow point contact rather than a more broad contact between the conductive metal parts. This can result in arcing or excessive heat buildup as large a current is being forced through too small a contact area. Dielectric silicon will do little or nothing with this very common type problem in old marinas/dock boxes.
- - The suggestions to support the dockside plug with some string or other means is very good as a wiggling or drooping plug can promote point contact between the metal conductors rather than a broad contact. It is common practice to take one or two "loops" around the dock box with the shore power cable prior to plugging it in to remove the problem of plug "wiggling" caused by boat movement.
- - Replacing your worn/burnt out plug/receptacles on an existing shore power cable with new ones is neither difficult nor complicated so long as you closely follow and triple check the proper polarity of each blade/pin.
- - Replacing your worn/burnt out traditional plug/receptacle with the new "improved" SmartPlug system requires that you also replace the ship's receptacle so it matches the new configuration of the new SmartPlug - and - either installing a "classical" plug on the other end of the shore power cable to match the existing dock box - or also changing the dock box receptacle with a SmartPlug receptacle. I don't thing the Marina is going to allow that as it makes that dock box unusable by other boats who have classical shore power cables. And if they did allow it you would have a rather expensive situation paying for a licensed electrician to alter the existing dock box.
- - All in all, the cost of copper electrical cable is not cheap, so replacing the burnt/worn-out plugs on your existing shore power cable with classical connectors is the least expensive system comparatively.

[AnchorageGuy]

For anyone considering the Smartplug, http://tinyurl.com/6dq5n45
Chuck

[Windseeker]

I went for the smart plug. The $250 hurt my feelings, BUT my local vendor had it in stock, it was a nice day to do it, and it's done! The one thing I liked is the fact that it has a thermal overload protection; and since my boat sits plugged in and unattended for most the time, it gives me Peace of Mind. I bought a small tube of $2.99 di-electric grease and lubed the connections.

I put in a couple of more pics. The heat vaporized the internal plastic on the boat connector. Also, the copper wire melted the insulation for about 2 inches. I had to strip back around 6" to get get good material.

It's fixed for now, and I really appreciate your help. I guess the Honda generator use and the connector burn was more of a coincident.

Here are my best practice "take aways" after listening to you guys:
1) Make sure your cord is firmly attached, turned and seated with the collar tightly screwed in.
2) Prevent movement on the cord at the connectors wherever possible.
3) If you are running excess cord into the cockpit instead of the dock, make sure the connected boat cord is angled down to prevent unexpected water ingress.
4)Take a couple of wraps around the piling with the cord at the shore power outlet.
5) If you are going to pressure wash your boat, you should disconnect the boat shore power connector.
6) Use Dielectric grease to prevent internal metal corrosion for electrical connections.
7) Regularly inspect it for burn marks or signs of excessive heat.
8) Nothing lasts forever.
9) Always go the the Cruisers Forum for great advice and feedback!

[goboatingnow]

The NMEA plugs that we all have used for years were never intended for marine service. If you dissect one you will find that there are dimples in the female receiving slots that are designed to engage, through spring action, the holes that you can see in the male plug. There are two problems with this arrangement; first, the twist part of the twist lock has to occur so the dimples line up with the holes. But over time this spring engagement gets weaker and weaker until you have a poor electrical connection.

Aint that the thruth. I have two boats one with the NMEA system ( and using 220) and one using the IEC 60309 system ( for those familar with euro marinas). I find the NMEA regulary generates arcing due to bad connections wheras the IEC 60309 with the larger surface area round pins, rarely does and takes far far longer to degenerate. Though equally 60309 plugs and sockets were also never intended for marine shore power useage.

Dave

[delmarrey]

The NMEA plugs that we all have used for years were never intended for marine service. If you dissect one you will find that there are dimples in the female receiving slots that are designed to engage, through spring action, the holes that you can see in the male plug. There are two problems with this arrangement; first, the twist part of the twist lock has to occur so the dimples line up with the holes. But over time this spring engagement gets weaker and weaker until you have a poor electrical connection.

I would tend to disagree. All the 110V outlets aboard US Navy ships are all twist lock (w/minor exceptions) and I suspect they were made that way during WWII for Military specs.