burnt 30 amp connection

[richk]

As I was leaving the boat yesterday, planning to hook up the 30A shore power, I noticed one of the three prongs on the plug was burnt. Both the male and female sides were burnt at the boat connection. It was the 'L' shaped prong. I suspect arcing is the culprit. I did not connect to shore power. What should I do next?

 

[Don S/V ILLusion]

replace the cable

this is a common problem. It isn't worth the cost and trouble of cutting and splicing in new ends on a supposedly weather-proof cable. More importantly, you might want to find out why it happened before you find yourself buying a new cable frequently. You should also inspect the dock connection to ensure that too isn't burned.

Some common causes are too much current, bad connections causing internal resistance and arching, corrosion on the dock side conenctor and misaligned connector pins.

 

[EvenKeel]

Make connection with power off

I don't know this from experience, but I've read in a number of places that the primary cause of burnt plug connections is having the cable hot while you are making the connection. You should make the connection with the breaker on the dock end shut off, or if you don't have access to that breaker, keep your A/C master switch off until everything is connected. This would also prevent some excitement if you drop the cable end in the water in the process.

Gary
Even Keel II

 

[Jim]

To much current

Are you using a single 30 amp connection to drive your AC unit and water heater? One has to go brother!

 

[filthy liberal scum]

power cable connections should be made with no load

cable connections should always be made with no load on them. this is why breakers and switches are made with spring loaded make and break connectors. that is to say that they make or break the connections quickly. that is so it minimizes the arcing when the connections are getting close to each other. some really big switches and breakers have their contacts immersed in oil to keep the contacts from being burned away. picture an arc welding machine. every time an arc is struck it melts the welding rod. same thing happens with a plug only on a much smaller scale.
so next is replace both ends of connection. cable and plug on where its plugged in on the dock. just replacing the cable won't solve the problem.

 

[Mike B]

Replace the cables

I also agree with replacing the cables but also check the other ends and sockets. It's a common occurance due to the terminals opening up over time. A loose connection produces resistance which in turn produces heat and melts your cable ends. As someone else mentioned it's also a good idea to make sure you're making and breaking the connections with the power turned off. I make a habit of checking the ends every time I disconnect the cord. Not only will this prevent arcing but it's just a good safety practice. You have to respect a cable with 30 amp capacity.
Mike