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Tis the season... to make sure your electrical connections aren't over heating!

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    Tis the season... to make sure your electrical connections aren't over heating!

    With the cold weather hitting the PNW, and us living aboard and having all the electric heaters running... I figured it was a great time to pull out the FLIR One Pro and do our quarterly check up. Since the last check up, I replaced the boat side shore power connection with a Smart Plug so it's a good idea to check for hotspots.

    It was interesting to note that at the outside shore power connector, the coax port had more heat loss than I expected.

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    Shawn Hammer and Geri Schaffer
    G-dock, Shilshole, Seattle
    2005 Meridian 490
    2016 Walker Bay
    M/V 2nd Circus

    Pretty cool and a very good idea. I bought my 4788 a couple years ago and shortly after i got it I found some AC wiring behind the distribution panel had melted the insulation and the #1 main breaker. Virtually every switch and circuit breaker connection was loose as it turned out.


    • MV2ndCircus
      MV2ndCircus commented
      Editing a comment
      that's one of the things I love about using thermal imaging. I shoot the outlets around the boat as well as the panels and I can see a loose connection before it's a problem. Now if only they could make a camera that shows corrosion between contacts...

    Timely. I was at the boat the other day and noticed we'd popped one of the 30 amp breakers in the panel. I shut some things off, including a couple heaters and re-set. I went to check things more thoroughly today and found that my boathouse shore power cable/boat connection had overheated...a lot. The connections had nearly welded themselves together. I'm pretty lucky no more damage was done. Replaced the cable from the boathouse and the 2 into 1 from the boat. Next will be pulling back the panel to make certain no damage was done there. I actually checked the cable from the boathouse and found that the damage went back several feet, overheating most likely the entire cable. No idea how long that had been going on. Likely do to a gradual deterioration of that connection. I tell ya...I can fix most anythng, but electricity and all its permutations is PFM to me.
    Toni Froehling

    Yelm, Washington
    1994 Hino powered 4788


      We got a 4588 a month ago and we like to spend a lot of time on the boat. Since we didn’t have diesel heat at the time the Admiral turned on too many electric heaters and other things. Previous owner installed a Smartplug and it thermal overloaded. Photo says it all.
      1992 4588
      Sea Nile

      Seadoo Wake 170


      • joe440
        joe440 commented
        Editing a comment
        30Amp plug. I don’t know how long or how many amps we were drawing. I suspect the plug was previously melted. I put on a new plug and now have my diesel heater going. No need for the electric heaters now.

      • guntar
        guntar commented
        Editing a comment
        Wow I didn't think a smart plug would allow that to happen.

      • mlewis100
        mlewis100 commented
        Editing a comment
        The Flir or infra-red is a great idea to see the high resistance points.
        I had a 30 amp smart plug do a similar thing. My feeling was; compared to the traditional 30 amp twist-lock, it didn't blow out at the actual contacts (leaving the big black battle scar on the boat) but instead where the wires are connected and melting the internals of the plug. If one is to invest in a smart plug, probably best to invest in a new cord and and perform high quality terminations (take care with stripping the wire not to remove un-necessary wire strands and be sure wire-to-plug connections tight). This is pretty all for nothing if the plug end ever dips into saltwater. When I setup my last shore cord, I suspect the aged wire came due eventually and high resistance became intolerable at the plug terminations. When I made up a new one I did use a new cord and took the best care possible in wiring it. My old cord never was submerged in salt water. I was lucky enough to find a still-in-new-packaging smart plug 30amp cord on craigslist for $100 Canadian dollars which may remove the issue altogether. I keep that cord onboard for use at visiting docks.
        I still believe in the smart plug concept (moving the place where meltdown occurs to a slightly better location).

        A better thermal protection that prevents arcing at the marina power source would be best. Not sure what that looks like...
        Check your power often and don't overload it.

      Florida has the same problem, stemming from AC use though. A boat at the marina by me burned down due to the shorepower cable catching fire.
      Now I see why many marinas do not allow liveaboards. When I got my slip up in Bellingham, it was because the marina just finished a whole new row of about 100 slips. They replaced the ones taken out by a liveabord fire.
      Huntington Beach, California
      2018 Element 16
      Currently looking for 32xx in South Florida
      Former Bayliners: 3218, 2859, 2252, 1952


      • MV2ndCircus
        MV2ndCircus commented
        Editing a comment
        I think liveaboards vary a lot, even within a marina and, it comes back to marina policies and how they enforce them. We've lived aboard since August 2019 and in that time, we've seen one boat fire two docks away from us. It was not a live aboard but was caused by an electrical issue - plug-in space heater left on the boat without anyone there. Fortunately, one of the live aboards near by spotted it early and called it in. The boat wasn't burned to the waterline and the marina didn't burn.

        That said, there are a few boats near me that I keep a close eye on - as in I hit their electrical connections with my FLIR one - so I at least know if that's increased risk. They're basically derelicts that the marina is violating their own policy by not removing. Living aboard though, gives me the opportunity to untie and leave the marina if there is a fire risk that I'm not comfortable with.

      One of my boat checks is to feel my electric cords every time I fill the water tank. As a liveaboard with an admiral that is still working and thus showering every day I check my cable at least weekly if not more. I felt the cable a week ago when I filled up before our cold snap and it was fine. After a week of running heaters 24/7 - baseboard- not space heaters on extension cords- this was the result.
      And by cold snap I mean low 20’sF and 8” of snow that is already completely melted. I don’t know how folks in REALLY cold climates do it.
      Drew Haas
      1998 4788 "Painkiller"


      • MV2ndCircus
        MV2ndCircus commented
        Editing a comment
        Damn Drew, that's a fast turn around and about enough to make me start twitching!

      I liveaboard in Toronto and tonight will be -20Celcius about 8 below zero Fahrenheit
      I have all electric heat.
      Make sure your connectors are salt and dirt free, corrosion is your enemy.
      Turn off the power at the tower before undoing a cord connector. That little arc degrades the connector a little bit each time.
      Use di-electric grease on each .connector inlet and outlet.
      Check for warm connectors often.
      If possible, get a slip with recent electrics delivering a full 120 volts. 110 volts at your boat increases amperage by 8%
      If using 50/125/250 power Balance your loads.

      Stay warm and stay safe

      If using plug in heaters I recommend Caframo or West Marine, also made by Caframo and get several running on 600 watts
      instead of running one at 1500 watts.
      "Adios Dinero"
      1997 3988 with new 330 Cummins
      Photo Credit: Whiskywizard


      • MV2ndCircus
        MV2ndCircus commented
        Editing a comment
        I like the idea of balancing the loads. I just wish I wouldn't have to rewire my AC panel to do it...

      Originally posted by joe440 View Post
      We got a 4588 a month ago and we like to spend a lot of time on the boat. Since we didn’t have diesel heat at the time the Admiral turned on too many electric heaters and other things. Previous owner installed a Smartplug and it thermal overloaded. Photo says it all.
      I seriously doubt that Smartplug unit had the thermal protection feature! You see, there are arguments against the auto reset thermal protection and Smartplug did produce units to conform to ABYC standards if this is what you believe in. Sounds dumb and yes it is, I'll let you judge for yourself. Here is an excerpt from this link which is a must read in it's entirety!!!

      EDIT: Went to the Smartplug site and there is no mention of the once highly advertised thermal protection. Seems like the had to conform to AYBC who would not allow it. Thankfully the one I had on the previous Avanti and the unit on the Carver were purchased before this feature was removed.

      For anyone interested, here is a link describing the once touted thermal overload feature.

      ​​​​​​IMPORTANT: There are some in the industry who feel an auto-resetting breaker, of any kind including thermal, is not safe. This mind-set & origin stems from breakers re-setting into a dead short, and I agree 150% with this. However resetting automatically into a dead short is not the same as a high resistance thermal shut down.


      Up until now we have had no shore power thermal breakers that trip on high resistance / temperature just on overload of the circuit or an imbalance such as an ELCI (basically a whole boat GFCI)..

      The argument the opponents (most likely the manufacturers who don’t care about safety) propose is this:

      Boat owner’s Darrell & his other brother Darrell awake in the middle of the night to no boat power.. Darrell & Darrell find no electricity at the AC panel. Darrell #1 opens the AC panel at the same exact moment the thermal breaker re-sets and gets zapped.

      While, in theory, this could possibly happen, it is about as likely as Rosie O’Donnell beating Lance Armstrong in The Tour de France. At least Darrell & Darrell were still alive to open the AC panel & not cooked medium rare in their sleep

      Follow me for a moment please;

      The same few folks (ABYC members & even instructors) & competitors of the SmartPlug arguing against the thermal-breaker in the SmartPlug 30A inlet have zero issues with auto-transfer inverters which can create the same exact Darrell & Darrell scenario they paint above, and use, to argue against the innovative and significantly safer SmartPlug..

      Once such competitor actually argues out one side of their mouth against the thermal-switch then out the other sells piles & piles of auto-transfer inverters…. Blatant hypocrisy? You bet…

      Follow me again please;

      Darrell #1 goes to the dock pedestal and physically unplugs the shore power cord. He yells down to Darrell #2 “Okay-dokey it’s safe now.” Darrell #2 opens the AC panel and ZAP………!!!!!!!!!!!!!

      Oops, the inverter transferred AUTOMATICALLY without requiring a manual-reset to produce 120V AC.…… D’oh.

      It is insanity to argue against the thermal-breaker in the Smart Plug 30A without also arguing against auto-transfer inverters, especially if they want to use the Darrell & Darrell argument….

      Like anything common sense should rule the day, but too often common sense is being waved bye-bye to out the back window of the school bus.. We now have a safer mouse trap & a better mouse trap but it will always get hung up with second guessers & direct competitors proposing poorly thought out & grossly hypocritical supposition like I just outlined. You will have to decide what is safer for your vessel.

      EDIT: SmartPlug has decided to offer a version of the 30A inlet without a thermal breaker to be in compliance with the ABYC standards against auto-resetting. Now if we could just get all those inverter manufacturers to… Aw $hit, I give up………
      Cheers, Hans
      2007 Carver 41 CMY
      Twin Volvo D6-370
      Montreal, Canada
      Midnight Sun I Photos


      • joe440
        joe440 commented
        Editing a comment
        When my shore power tripped out. I removed that shore power cord with another and had no power to the main panel. I checked the shore power with my voltage detector and had power at the smartplug. I don’t recall the amount of time but after a while the power came back on to the main panel. If it wasn’t a thermal reset, what was it?

      What camera do you use to see the thermal differences? That is pretty cool!


      Whats the weather like on our boat

      Where are we right now?


      I left my slip on Monday to haul out. Disconnecting the power cord after shutting dock power off I noted small scorching on the female plug at the 3rd receiver. The 3rd receiver is the heater bank.
      The Marinco 30amp cord is the screw collar connection. The male “L” connector was a bit discolored but not scorched. 2018 I replaced the front 2 male connections, wiring & crossover switch. Also went to a Y connector. Replaced the power cords with Marinco quick clamp connectors (hate them). Went back the threaded collars.
      I have order a new power cord for that 3rd receiver and fashioned a support to minimize any shifting st the connections.
      Lube ? & Check these connections frequently and assure that they are solidly & securely connected & not scorching. Also insure well!
      1990 4588
      Port Hueneme Ca