Reminder: Watch those power cords

Just a reminder to keep and eye (and hand) on your shore power cords. I try to make it a habit to feel the cord ends as I approach the boat but I often forget.

I went to the boat last week and touched the cord entering the boat. All was well on the boat end. When I went to disconnect the cord from the power pedestal, the plug end felt warm on the bottom side. I found that one prong was darkened and hot to the touch. It was discoloring the yellow plastic around the base of the prong and the outside of the plug was also starting to discolor.

I replaced the cord with a spare and returned the cord to West Marine where I purchased it 3 years ago. West Marine replaced it with a new cord. The marina is in the process of checking the power pedestal for any issues.

I will focus more to keep those contacts clean and dry.

A good habit to develop for sure. Almost do it unconsciously now. Nothing beats condition based maintenance practices.

Great reminder, thank you.

FlyWright said:

I replaced the cord with a spare and returned the cord to West Marine where I purchased it 3 years ago. West Marine replaced it with a new cord. The marina is in the process of checking the power pedestal for any issues.

I will focus more to keep those contacts clean and dry.

Click to expand...

Al
Thanks - great reminder
Was the cord a Marinco by any chance?
I've heard they will replace cords that show signs of overheating but I haven't been able to confirm.
I do USPS Vessel Safety Checks and would like to know for sure to advise boat owners when I find one of these... and I have found several during inspections.

Question:

When leaving a boat connected to shore power for an extended period (winter layup) would it be a good practice to use a dielectric compound on both the shore side and boat side receptacles?

Tom

tpbrady said:

Question:

When leaving a boat connected to shore power for an extended period (winter layup) would it be a good practice to use a dielectric compound on both the shore side and boat side receptacles?

Tom

Click to expand...

It certainly can't hurt as It acts as a moisture insulator. We use it in car connectors, Battery connections etc. all the time..

Something to add: a 30 amp service is very rapidly used up by heaters and water tanks, plus most forget about their battery charger. I'm not suggesting that's the case here, but it's worth checking. Many just keep plugging stuff in until the breaker blows but that's not how it works. You can overload a circuit below breaker cut-off which results in dropped voltage and too much heat in the cable before the breaker pops. Weak, high resistance connectors like typical boat cables will overheat, melt and if you are not very lucky you will have a fire. Add flaky dock connections and salty water....

Heaters
Battery charger
Lights
Hot water tank
Intruder alarm
Block heaters
Galvanic detector
Propane sniffer
Wired smoke detectors

Read the labels on the devices, tot up the total wattage you are trying to consume on your boat and be prepared to be surprised. If you have a 20 amp service, that's even worse.

Dielectric grease is a good idea for shorepower connections. It doesn't have to be "long term", use it as it wears off.


An infrared non contact thermometer is better for measuring plug and socket temperatures than your hand. They have other uses around a boat and are a good addition to your tool box.

Bacchus said:

Al
Thanks - great reminder
Was the cord a Marinco by any chance?
I've heard they will replace cords that show signs of overheating but I haven't been able to confirm.
I do USPS Vessel Safety Checks and would like to know for sure to advise boat owners when I find one of these... and I have found several during inspections.

Click to expand...

Yes, it was a Marinco power cord. My new cord states it has a 5 year warranty.

Thanks for the reminder. I found the "boat end" of my cord warm and discolored around one pin. Replaced the connector.

Ken

upgraded to 50 amp...as much for the better connectors than total power...but that is nice too.


no issues after decades of having browned 30A plugs or getting to a marina and having to plug into one.


not looking back and smiling.....

WesK said:

Dielectric grease is a good idea for shorepower connections. It doesn't have to be "long term", use it as it wears off.


An infrared non contact thermometer is better for measuring plug and socket temperatures than your hand. They have other uses around a boat and are a good addition to your tool box.

Click to expand...

Disagree. The cord and connector should be cold to your hand. Any feel of warmth, even in hot weather, is a danger sign.

tpbrady said:

Question:

When leaving a boat connected to shore power for an extended period (winter layup) would it be a good practice to use a dielectric compound on both the shore side and boat side receptacles?

Click to expand...

We periodically inspect the connectors on both ends of our groundpower cable and use dielectric grease on the connector blades. In addition to checking both ends of the cable for heat every time we arrive at and leave the boat we also unplug and smell the ends for any telltale "burned electricity" smell.

We also check the AC plugs on anything we have plugged into the boat's AC outlets, particularly the two heaters and the extension cord powering one of them that we leave on the boat during the winter, to make sure they are not warm.

We noticed last year that the female end of the extension cord we used the most on the boat was slightly warm while powering one of the heaters. We immediately bought a replacement cord and tossed the old one.

I just wish people would lift their cords out of the water.

what_barnacles said:

I just wish people would lift their cords out of the water.

Click to expand...

How do they stand it?!! That bothers me too. We always make an effort that the cord is far from in the water.

I went to the SmartPlug system. Much better design with more contact surface area, plus built in heat disconnect. Solid lock and easier plug in.

Smart Plug

Ron T said:

I went to the SmartPlug system. Much better design with more contact surface area, plus built in heat disconnect. Solid lock and easier plug in.

Click to expand...

+1 Smart Plug is definitely a big improvement

Ron T said:

I went to the SmartPlug system. Much better design with more contact surface area, plus built in heat disconnect. Solid lock and easier plug in.

Click to expand...

What he said! Also the Admiral loves it (so do I).....

The hand method is good. As mentioned ANY heat is too much. Your hand can detect that easily.

Lots of sprays that will also keep moisture driven corrosion at bay. Not for ever but slow it substantially.
I also tie my cord end to the post after a wrap around the post so the plug is not being strained.
Also tied to the nearest boat stanchion so it stays out of the water allowing enough slack to allow for boat movement.

On your twist locks back roll it before plugging in to the receptacle. Use a couple feet of cord as part of that backroll so not just the very end is backrolled. That backroll should be easily put into the cable. Most cords have twist memory to them and that back roll will tend to hold the junction together. I've seen lots of them that the memory in combination with a pull or weight has almost undone the prongs.

I wonder how much stress I put on the plug ends when stuffed into the cable storage box.

I minimized connection problems by hard wiring the boat ends of my two 30amp cords.
That eliminated six moving connections. The cords are pulled into the boat from a locker inside the boat. A few examples

Marin said:

............. We noticed last year that the female end of the extension cord we used the most on the boat was slightly warm while powering one of the heaters. We immediately bought a replacement cord and tossed the old one.

Click to expand...

I have found that on many heating appliances, the cord and plug will get warm in use, even straight out of the box. Bad design for sure but it happens.

There's "warm" and then there's "too warm".

Keeping cable out of the water is simple for those of us in 2' and less of tidal change. However, those in 9'-10' or more with fixed docks do have a more difficult challenge, especially if they are fairly level with the power stanchion at one extreme or the other.

I too went with the "Smart Plug" and like the design and consider it a great improvement to the old system. I know some on here thing of them as an unnecessary expense but I disagree, and I needed to replace the old inlets and cable as to an overheating and charring issue anyway.

I have 2 30A inlets (one for house and one for AC units) and I want to keep it that way so changing to a 50A is not what I want.


Great point regarding space heaters and timely, they eat up amps.

I agree wire and plug should not be much above ambient temp, as in slightly warm.



I will check today as it has been a while, darn cables so easy to overlook.


We had a boat fire two weeks ago directly behind me across the fairway on A dock. From what little I have learned it was started by an never working water tank gauge that was installed by the PO and was ignored and in place for over 5 years. Seems weird but that is all I know, boat was a 40+ planing cruiser and is totaled no damage to surrounding boats.

SCOTTEDAVIS said:

We had a boat fire two weeks ago directly behind me across the fairway on A dock. From what little I have learned it was started by an never working water tank gauge that was installed by the PO and was ignored and in place for over 5 years. Seems weird but that is all I know, boat was a 40+ planing cruiser and is totaled no damage to surrounding boats.

Click to expand...

Boat fires are in many ways not all that different from house fires, except for the availability of fuel as accelerant. The majority of house fires are started by a few things. Kitchen fires from unattended items, electrical fires, cigarettes (often in bed), and space heaters. Most boat fires are caused by the same items. Now, boat fires can then get out of control faster, but that's not just due to fuel, also to the materials used in construction and to the small spaces. They then spread much faster at marinas due to the proximity of other boats and the lack of any sort of firewall.

The smart plug may indeed be a better design, but it's not standard so if you're out somewhere and damage your power cord you may have a hard time finding a replacement.

I suppose you could carry a spare but that's an added expense. Also, you couldn't' string two cords together to make a longer one when needed.

WesK said:

The smart plug may indeed be a better design, but it's not standard so if you're out somewhere and damage your power cord you may have a hard time finding a replacement.

I suppose you could carry a spare but that's an added expense. Also, you couldn't' string two cords together to make a longer one when needed.

Click to expand...

Sure you can, only the boat end is an odd fitting the other end is a standard push/twist so that it will fit the dock pedestal, just add a standard cord to that end and you're set.

You are correct regarding the boat inlet needing the push plugs but if you are worried about that just carry an extra Smart plug and you are all set to attach it to any boat cord.




or carry one of these adapters...but remember that this defeats the purpose of getting the poor connection off and away from your boat.

While I can see that having a SmartPlug is an upgrade on the boat connection side, in my case, it was the dock side with the standard 30A plug that failed. This connection has been treated with CorrosionX to inhibit corrosion and high resistance connections.

Nothing would have changed if I had a SmartPlug except that I'd have a tougher time finding a fast replacement. The risks at the power pedestal remain the same.

Web sites pbase.com and Panbo: The Marine Electronics Hub /smartplug have good illustrations why the smart plug is so much better.

Slight drift, but checking cords online, incl Marinco, some are said to be 125v rated, some 125/220v rated. Are there differences?