Marinco Power Cables

[btrayfors]

Thirty-amp connectors are a perennial problem in marinas. I've seen many failures and meltdowns over the past couple of decades. Many of these could be traced to "user failure", i.e., overtaxing the connectors by overloading them, not cleaning them, not keeping them dry, etc., etc.

The sad truth, however, is that we're now seeing FAR TOO MANY failures of 30A Marinco connectors to believe that its always "user failure".

First, the design stinks: these things cannot handle anywhere near 30A continuous power, without heating and burning.

Yes, do everything possible to keep contacts clean and dry, and try to limit power draw to not more than 25A or so. That will help.

But, bottom line, IMHO these connectors are real crap. Be very wary of them....i.e., ALL 30A connectors....but, especially, those recently coming out of Marinco. These seem to be substandard in construction.

Is this really the best we can do?

Bill

[SteveInMD]

Are you getting a full 120 volts? If the marina is providing less, that could cause the problem too.

The cords may be crap - I have no way of knowing for sure. I'm just trying to mention thing that you have some control over.

[ebs001]

CD, I have had the same problem. Has it been the same slot on the receptacle end in both your failures? I have a feeling that all the failures are on the same slot and that this is a result of not completely turning the plug before tightening the holding ring and because of the configuration of the blades full contact is not made. If this is the case it is neither corrosion nor poor workmsship that are the cause of the failure.

[Cruisingdad]

Originally Posted by SteveInMD

Are you getting a full 120 volts? If the marina is providing less, that could cause the problem too.

The cords may be crap - I have no way of knowing for sure. I'm just trying to mention thing that you have some control over.

I had already thought of that too.

Yes, on a normal day, we are getting good power. The question is whether it stays good?? That, without putting it on a meter/printout, I cannot know. But the problems associated here are not solely out of my marina which leads me to believe that, unless highly coincidental, it is not the major problem.

- CD

[Cruisingdad]

Originally Posted by ebs001

CD, I have had the same problem. Has it been the same slot on the receptacle end in both your failures? I have a feeling that all the failures are on the same slot and that this is a result of not completely turning the plug before tightening the holding ring and because of the configuration of the blades full contact is not made. If this is the case it is neither corrosion nor poor workmsship that are the cause of the failure.

I am not sure about that. I would have to check.

- CD

[Cruisingdad]

Originally Posted by btrayfors

Thirty-amp connectors are a perennial problem in marinas. I've seen many failures and meltdowns over the past couple of decades. Many of these could be traced to "user failure", i.e., overtaxing the connectors by overloading them, not cleaning them, not keeping them dry, etc., etc.

The sad truth, however, is that we're now seeing FAR TOO MANY failures of 30A Marinco connectors to believe that its always "user failure".

First, the design stinks: these things cannot handle anywhere near 30A continuous power, without heating and burning.

Yes, do everything possible to keep contacts clean and dry, and try to limit power draw to not more than 25A or so. That will help.

But, bottom line, IMHO these connectors are real crap. Be very wary of them....i.e., ALL 30A connectors....but, especially, those recently coming out of Marinco. These seem to be substandard in construction.

Is this really the best we can do?

Bill

Hi Bill... how are you?

Thanks for the input. Yes, I think I agree with you. But you would think (using the 20% rule), they would over size their cords/connectors for continuous operation at 30 instead of 80% of 30A. I wonder if that is not the case?

- CD

[capn_dave]

On most cases at our marina, the plastic ring that is supposed to hold the connectors tight is broken or was not used. The twist lock function of the plug itself will not hold the plug in.
Insurance companies are checking this when there is a claim.
That plastic ring breaks easily when dropped, and I don't think it can be replaced, so you have to buy a new shore power cable.
Hummmmmm! could this be on purpose?

Fair Winds

Cap'n Dave

[ebs001]

I think you will find that it is always the same slot. It would therefore appear to be a design flaw in their female cap. I do not recall seeing this problem anywhere else, so it may be more of a problem with Marinco. I do know that by insuring to turn the female cap to the lock position and tightening the locking screw ring it doesn't heat up. Note that once heating starts the contacts produce their own resistance furthering the heat build up so periodic cleaning will help. My feeling is that there should be a positve feeling of locking the plug in postion and I certainly don't feel that. Next time I'm in Home Depot I'm going to check other manufacturers male and female cap connections.

[camaraderie]

I am dealing with different cordsets every day...maybe a few hundred each year and would say that the majority of cordsets have similar burning to what is shown. I would guess that 90% of the cordsets are marinco since it is what is generally available and sold at the major boating stores. I rarely see any burning on 50amp sets and I have always attributed it to the much more robust contact and locking mechanism. I think the 30a plug/receptacle design is flawed regardless of the manufacturer...but how do you change a "standard"??

[sailingdog]

It is pretty tough to change a standard without overwhelming proof that a newer standard would have significant benefits...

Originally Posted by camaraderie

I am dealing with different cordsets every day...maybe a few hundred each year and would say that the majority of cordsets have similar burning to what is shown. I would guess that 90% of the cordsets are marinco since it is what is generally available and sold at the major boating stores. I rarely see any burning on 50amp sets and I have always attributed it to the much more robust contact and locking mechanism. I think the 30a plug/receptacle design is flawed regardless of the manufacturer...but how do you change a "standard"??