Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-14-2019, 03:57 PM   #1
Member
 
City: Jacksonville, Florida
Vessel Name: The Boardroom
Vessel Model: 1983 Marine Trader Labelle 43
Join Date: Sep 2018
Posts: 16
Scary Breaker Trips

Well, we started living aboard on December 17th the day we knocked the house down, (she was flooded by Irma). We bought the boat and spent four months refitting her for live aboard, mostly fixing a number of electrical issues to do with a blown inverter, fixing the typical marine trader window leaks and installing a Type I MSD so pumping is not necessary.

The first month went well, but the second month we had problems with the 50 amp breaker on the temp pole for the dock. It went from once every two weeks tripping, to daily so we got a replacement. No more pole tripping.


However, a week or so goes by and now one of the thirty amp breakers on the panel tripped about once every three weeks or so, then every two, then once a day, the more. We started better power management and it was better, but it still tripped on occasion. I called my Marine Electrician. He came out, looked at the breaker and pronounced it OLD and ordered a new one.

The new one broke on entry, bad plastic mold, but his assistant kept complaining about how hot the old one was. So, the electrician checked the cables and boom.

So, $500 new shore cables, new inlet, new breaker and we are OK. Never smelled it once! Moral, do not ignore the breaker, it is trying to tell you something. No internal wires were melted, only the inlet and the shore power cable.
Attached Thumbnails
IMG_20190614_160919.jpg  
Howard Arner is offline   Reply With Quote
Old 06-14-2019, 04:04 PM   #2
Guru
 
dhays's Avatar
 
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
Good reminder. However, I’d like of like to know why the inlet got so hot it melted? What was the condition of the end of the cable? What was the condition of the inlet? Was a dielectric grease used to protect the connections?
__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Old 06-14-2019, 05:06 PM   #3
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Join Date: Aug 2011
Posts: 6,348
Grab the ends of those cables every day if you can. If you feel warmth, investigate.
__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is offline   Reply With Quote
Old 06-14-2019, 06:04 PM   #4
Guru
 
tiltrider1's Avatar
 
City: Seattle
Vessel Name: AZZURRA
Vessel Model: Ocean Alexander 54
Join Date: Aug 2017
Posts: 4,309
The shore power cord ended up in the water at one point. Takes years for the salt to corrode the female socket but eventually you get a catastrophic failure.
tiltrider1 is online now   Reply With Quote
Old 06-14-2019, 07:19 PM   #5
Moderator Emeritus
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Black Dog
Vessel Model: Formula 41PC
Join Date: Jul 2015
Posts: 21,191
The 5L-30 plugs do not have a very large contact area to conduct up to 30 amps. They probably should be only run at 70% of the 30 amps or so. A little bit of corrosion on the contacts will quickly become a problem. I went to Smart plugs for this reason. CMS web site has a very good review of this situation. I can’t believe that it took a marine electrician several tries to find this problem, it would be the first thing I would look at if the breaker is repeatedly tripping. It is a very common problem.
Comodave is online now   Reply With Quote
Old 06-14-2019, 07:26 PM   #6
Guru
 
boathealer's Avatar
 
City: Looking
Vessel Name: --
Vessel Model: Between boats
Join Date: Aug 2017
Posts: 1,190
Corrosion on contacts equals resistance. Resistance on contacts means voltage drop and more current being drawn by onboard devices. Higher current through a resistance equals heat. Lots of heat equals melted plug. Guess which terminal had the corrosion?

Keep those shore power contacts CLEAN (both sides). Dielectric grease does help keep corrosion at bay.
boathealer is offline   Reply With Quote
Old 06-14-2019, 10:05 PM   #7
Guru
 
dhays's Avatar
 
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
I use dielectric grease on mine, but it is time to remove the dock pedestal end and clean, inspect, and apply new dielectric grease. I have been doing this a couple times a year but it has been longer than 6 months since I last did it. This thread is a good reminder for me.
__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Old 06-14-2019, 11:24 PM   #8
Guru
 
AlaskaProf's Avatar
 
City: Tacoma, WA & Ashland, OR
Vessel Name: boatless, ex: Seeadler
Vessel Model: RAWSON 41
Join Date: Jun 2016
Posts: 2,234
Aviation rule: Reset a breaker once; NO MORE. Fail the system and down the aircraft on arrival.
AlaskaProf is offline   Reply With Quote
Old 06-15-2019, 10:05 AM   #9
Member
 
City: Jacksonville, Florida
Vessel Name: The Boardroom
Vessel Model: 1983 Marine Trader Labelle 43
Join Date: Sep 2018
Posts: 16
Quote:
Originally Posted by AlaskaProf View Post
Aviation rule: Reset a breaker once; NO MORE. Fail the system and down the aircraft on arrival.

That should have been a rule for my boating too. My problem, or stupidity, was that I just thought the breaker was old and getting "touchy" as we were running both the window shaker and the main AC on that leg pulling about 15 amps. So much for thinking.


Funny thing is, I am a programmer, I should know better!
Howard Arner is offline   Reply With Quote
Old 06-15-2019, 10:12 AM   #10
Member
 
City: Jacksonville, Florida
Vessel Name: The Boardroom
Vessel Model: 1983 Marine Trader Labelle 43
Join Date: Sep 2018
Posts: 16
Quote:
Originally Posted by dhays View Post
Good reminder. However, I’d like of like to know why the inlet got so hot it melted? What was the condition of the end of the cable? What was the condition of the inlet? Was a dielectric grease used to protect the connections?
Dave, this shows the value of a good marine surveyor, as I had a terrible marine surveyor recommended by the boat broker. I pointed out the small defect in the cable and he said, "Oh, that is from when the battery charger/inverter blew. That chord is fine!"

I have always had boats 20' or less, no shore power, just 12 volt systems and chargers. This is my first big one. I am learning a lot, but no one mentioned "Dielectric grease" to me. I am on my way to WM to get some now, thanks.


As to the condition of the cable, it looked good other than that small melt around one connector which surveyor said was fine. Inlet looked good too, but I bet if I would have looked harder I would have seen some rust. Just glad we did not have a fire. I feel these puppies each day now when I exit the boat.
Howard Arner is offline   Reply With Quote
Old 06-15-2019, 10:14 AM   #11
Guru
 
FoxtrotCharlie's Avatar
 
City: Mississippi
Vessel Name: ADAGIO
Vessel Model: CHB Present 42 Sundeck
Join Date: Jul 2014
Posts: 920
Yep I've had several friends/associates that have had issues with the old 30AMP plugs/inlets. When we were looking at boats always assumed I would switch to Smart Plug if we bought a 30A boat. But ours is a 50Amp/125 boat and the old 50A plugs are much more robust and we have had no problems (Did put a new shore -end plug on one of the 3 25ft lines). With both 16k AC's, water heater and microwave running (and all lights are LED) we draw around 36amps.
FoxtrotCharlie is offline   Reply With Quote
Old 06-15-2019, 10:29 AM   #12
Guru
 
Northern Spy's Avatar
 
City: Powell River, BC
Vessel Name: Northern Spy
Vessel Model: Nordic Tug 26
Join Date: Feb 2012
Posts: 4,075
The nickel plated pins on the smart plug receptacle are corrosion free and look just like the day I installed it.

Everyone frets about untinned wire on a boat, when the ABYC NEMA plug is probably the most corroded, and therefore high resistance, component that is in the electrical system.
Northern Spy is offline   Reply With Quote
Old 06-15-2019, 12:07 PM   #13
Moderator Emeritus
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Black Dog
Vessel Model: Formula 41PC
Join Date: Jul 2015
Posts: 21,191
Breaker rarely go bad, not impossible but certainly not frequently so that would not be at the top of my troubleshooting list. However the shore power cables are notofor melting due to resistance.
Comodave is online now   Reply With Quote
Old 06-15-2019, 12:31 PM   #14
Guru
 
dhays's Avatar
 
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
As others have noted, if I had a 30amp inlet, I’d replace it with a Smart Plug. I did this on my last boat. Now with a 50/120 inlet, my only problem is that it is getting to be rare. It is a very solid connection and I don’t worry about it.
__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Old 06-15-2019, 01:38 PM   #15
Guru
 
FoxtrotCharlie's Avatar
 
City: Mississippi
Vessel Name: ADAGIO
Vessel Model: CHB Present 42 Sundeck
Join Date: Jul 2014
Posts: 920
Quote:
Originally Posted by dhays View Post
As others have noted, if I had a 30amp inlet, I’d replace it with a Smart Plug. I did this on my last boat. Now with a 50/120 inlet, my only problem is that it is getting to be rare. It is a very solid connection and I don’t worry about it.
Yep, hard to find 50A 120 pedestals. First thing I bought was an expensive adapter for 50A 120 to 50A 240. The boat had one for 50A 120 to 30A.
FoxtrotCharlie is offline   Reply With Quote
Old 06-15-2019, 05:55 PM   #16
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,791
Check your loads. There is nothing wrong with the “normal” 30 amp plug as long as its clean and not overloaded.

30 amps is 3600 watts: one battery charger, one hot water tank and a few lights. That’s it. 90% of maximum load is 3250 watts. More than that and the available voltage drops and you get these wiring issues.

Monitor your loads! 50 amps is 6000 watts, that’s one hot water tank, one battery charger, fridge, lights, maybe an air conditioner but not a microwave and a toaster. 90% is 5400 watts. That’s 3 normal kitchen appliances and a few lights and NOTHING ELSE.

Shore power will never give you as much power as your house, did I say don’t overload!?

I’ve been yapping about this forever and nobody seems to pay the slightest notice. Check the voltage at any outlet and if it is less than you expect, ie less than 120, you are overloaded and a Smart plug won’t make a particle of difference.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 06-15-2019, 06:09 PM   #17
Veteran Member
 
City: Seattle
Vessel Name: Cygnus
Vessel Model: Meridian 391
Join Date: Aug 2017
Posts: 98
How do people monitor there loading? Do you run a amp measuring clamp and just turn items on and off to get the draw? Or is there a table of common loads? Like on marine ac unit is xxxx Watts? Is there something I could hard wire into my 120v system that is like a Killwatt meter for the boat? My main panel only has voltage meter FYI.

I have a shunt on my house bank connected to monitoring system. Measures amps in and out real time. Very useful
Barabus is offline   Reply With Quote
Old 06-15-2019, 06:14 PM   #18
Moderator Emeritus
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Black Dog
Vessel Model: Formula 41PC
Join Date: Jul 2015
Posts: 21,191
My main electrical panel has meters for voltage and current for both 12 volt and 120 volt. I do have to select which 30 amp inlet the meters are monitoring with a small switch.
Comodave is online now   Reply With Quote
Old 06-15-2019, 07:08 PM   #19
Guru
 
syjos's Avatar


 
City: Gig Harbor
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 2,315
I have 2 Blue Seas 8247 digital panel meters that are multifunction.

I mounted one coil at the inlet before the inverter/charger and another coil after the inverter.

An amp meter measuring only at the panel will give an erroneous reading depending on if the inverters transfer function is utilized.

With the inverter wired directly to the shore power for transfer function, reading amps at the panel does not measure the battery charger load.

Victron Multiplus has a feature to automatically turn off the hot water tank when on inverter. That doesn't get measured at the panel either.
syjos is offline   Reply With Quote
Old 06-15-2019, 07:15 PM   #20
Guru
 
dhays's Avatar
 
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
Like others, I have a Blue Seas digital panel that gives info on my AC loads. I do keep an eye on it to make sure that I’m not pushing my loads too high. It means that I have to be selective as to what AC loads are running.
__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Reply

Tags
breakers, breaking bad, telling you something

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 12:39 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012