Shore Power Issues

[CaptainJB]

My 2002 356 has presented some issues with burning of the shore power connector, both on the shore cable side and now on the boat plug

I have replaced the shore cable female plug twice before and when I did I cleaned up the 30 amp connector on the boat

I now have to replace both

I seem to have no problems with shore power in the boat. Only had one instance when the master breaker tripped and that was years ago during a terrible lightning storm. Boat was not hit but I think there was a surge in shore power

The only indicator I have of a problem is a hum in the VHF when connected to the shore power, but that is it.

I plan on checking all the shore power connections,...... ring out the basic wiring for hi resistant shorts

Anyone have any other ideas?

 

[Don S/V ILLusion]

how much power are you drawing through the shore power cable under max load?

 

[Guest]

Power

Don appears to be onto something here. Can you provide more details about at what times does the burning occur? When you first connect shore power after a cruise when the batteries are low, or when certain appliances are turned on?

Bad power habits can yield the results you refer. I first always turn off the boat's shore power switch on the breaker panel or at the dock power pedestal to stop the flow of electricity before I disconnect either end of the shore power cord. Several years ago, before I realized what I was doing, I did burn the cord plug and socket slots because I failed to turn off the flow of electricity first before disconnecting the shore power cord. Perhaps this might be a cause.

Our boat is set up for 60 amps of service with dual 30 amp cords, but I manage our boat's consumption to 30 amps supplied by the dock power pedestal. When we return from an extended cruise with low batteries, I know that the charger is going to use most all of the 30 amps to bulk charge the batteries for at least the first 30 minutes. After that I can bring other AC appliances on line without fear of tripping a breaker.

I also know that during the winter while at the dock I'll run only one of our two heat pumps that each will draw about ten amps. The hot water heater draws ten amps, the hot plate for cooking about ten amps, entertainment about five amps, and before you know it breakers are a popping unless you manage it to the 30 amps.

Lots of factors at play here, but I suspect that unless you are stopping the flow of electricity, the cause of the burned plug and/or socket is that which I described above.

Terry Cox

 

[CaptainJB]

Power Consumption

In answer to the question, about power consumption, I am not a power hog

When I plug into the dock, I allow the batteries to charge for a few minutes then I turn the airconditioner on 7-8 amps (not counting surge)

When I leave boat, the only things I leave on are air conditioner, and refrigerator (12V).

Consider I have a 30 amp system, I do not see this as a heavy load on the system

 

[CaptainJB]

Safety Pratices

I should have added, I also do not turn any power on until after I connect shore power cable

Then I turn power on dock pedestal, then the circuit breaker on the a-c panel in the boat

 

[Buck420]

I used to have the same problem. Burned up a couple of power cord sets and a couple of female boat plugs.
A certified marine electrician strongly suggested using dielectric grease at all boat and shore power connections....
http://www.jamestowndistributors.com/userportal/show_product.do?pid=8196
I've had no problems for the past 2 years now that I have been using it.

 

[KD3PC]

echo Buck,

after burning an outlet on the boat, and a cord in the same year, I replaced the bad stuff and used no-alox this go round, we will see how it works.

I too am careful about the start up and placing of cables, always under 25 amps, each side and such.

keep us posted
dave

 

[Benny]

Check the weather seal on your installation and the lock ring. A water leak or a loose plug can cause problems. Your power draw should not be a problem. I'm curious why you leave your a/c unit on when you leave the boat. We run a dehumidifier to keep things dry and mildew free while avoiding having to run the a/c. It is my way of thinking that an a/c unit has a life of a limited number of hours and that I would want to enjoy them while I'm aboard while delaying replacement ($$$) time. I'm on our second dehumidifier unit in the last 5 years.

 

[Sandra]

A new shore power option

Hello there,

Just saw your post through a twitter and thought I would reach out to let you know about www.smartplug.com A new shore power option that addresses the issues of burnt plugs. The basic flaw is that the points of electrical contact (the blades) are both exposed to the elements and responsible for bearing the physical stress placed on the plug due to movement or tension in the cord. With only one L-shaped electrical blade holding plug to receptacle, there is no guarantee of a secure connection or protection from corrosion due to exposure to the elements. This physical stress and inevitable corrosion cause the blades to work loose resulting in electrical arcing, overheating and if gone unnoticed, fire.

The SmartPlug is a revolutionary shore power system, At the core of the patented SmartPlug concept is its signature intuitive shape and straight-in sleeve design, rendering the problems with blind connections and arcing/overheating (due to tension and corrosion) a thing of the past. The triple weatherproof seals keep the internal electronics free from moisture, and the multi-point locking system provided by the stainless steel side levers and locking cap make the plug virtually impervious to the most extreme of environments. All these features of SmartPlugs combine to eliminate all of the major causes of overheating and burning found in the current twist lock standard today.

This is a major problem in the industry, 55% of all marine electrical fires are caused by shore power failure/overloaded circuits. Scary. Now there is a new option, finally.

 

[CaptainJB]

Thank you

I want to thank everyone for their help

Tomorrow I will address the issue

Sandra, I particularly like your solution, will evaluate the "Smart Plug"

As for Benny's question, I have chosen to leave the air conditioner on because I have found in many instances the system are better run than left idle. Idle systems corrode faster than running systems

I by no means over use. But I do keep the air conditioner on most of the time either cooling 80 degrees, or the cool/humidify cycle

In the 5 years I have been in Florida I have had two problems, cooling pump, and the thermistor.

Both were easily diagnosed and fixed by me

Thanks again everyone

 

[Dan Johnson]

Captn JB...

You didn't mention what sort of battery charger you are using and if it is always turned on when shore power is connected and turned on.

If the VHF is humming when it is turned on while the ac power is on, I would suspect that the charger may be the source, possibly caused by a surge or lightning strike since you are in Florida (the lightning capital) and you stay connected to shore power when away from the boat. Do you leave the charger on too?