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Low Voltage Anarchy


Hawaiidart

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Let me be honest: I know little about electricity other than the difference between AC and DC. I read The Last Days of Night and know what Telsa was working on versus Edison, who apparently was something of a con man.  I can attach the green wire to the green wire and the red wire to the red wire.  My-ahem- current problem is that I seem to have low voltage coming into my boat.  I am plugged into a 30 amp outlet with a 20 amp breaker.  How can I tell if the problem is with the electrical box on the dock or something with my boat?  If I put a multimeter into the outlet, what do I look for?  What do I test on the boat? What do I look for? Any advice?  My indicator is that when plugged into a different box with the same amperage I was able to run my electric heater and get it toasty warm.  In my present box, it gets tepid.  In order to run the microwave, I have to turn everything else off, which again was not a problem before.  When I attempt to to use two high output devices I get a warning light on the panel telling me the the charge rate is down to 10.20 amps.  Sometimes the breaker on the AC panel in the boat will trip.  None of this was a problem before.

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If the only difference is which shore side outlet you plug into, then the problem is the outlet wiring. The charge light - what is it wired to??? But first analysis is that one outlet cannot supply enuff amps to run things on the boat all at once.

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5 hours ago, Henley Hornbrook said:

...... My indicator is that when plugged into a different box with the same amperage I was able to run my electric heater and get it toasty warm.  In my present box, it gets tepid. ....

 

You need a heater in Honolulu?

present boat- that I'm living aboard more or less, is in Anacortes, WA.  Temp in the 40's at night.  

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Sounds to me (and I know nothing) like you have a ground leak/short, that is seeping your amperage. Do you have sacrificial zincs that may have dissolved?

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If you are in Anacortes you are probably paying a bit for moorage of which functional shore power is part of. Offset voltage is almost always related to the supply, dock,  and can be quite dangerous as it can cause electrical things to let the smoke out.

Start with having the marina make sure you are getting what your supposed to.  Most marinas with high and low voltage options, 120v and 220 or 30 and 50 amp services will have multiple phases of 120 volts going to power pedestals, for this reason you may be fine plugging into o e box but not another.  If there is a high load somewhere upstream it could drop the voltage on one leg.  

It is possible it's something on the boat bad wiring or overloaded.  Electrical space heaters can have a huge draw.  It was pretty common when we were in the PNW to run a dedicated power to a dock pedestal for a boat heater.  Keeps it off the boat wiring and if it trips the boat is not loosing power.

In any case it's a leave off till you know what's going on scenerio.

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2 hours ago, Hawaiidart said:

present boat- that I'm living aboard more or less, is in Anacortes, WA.  Temp in the 40's at night.  

The first pedestal you plugged into cannot feed the rated amperage. This is the marina's problem. Plug into the pedestal which CAN support your boat.

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There's many options to look at, How the boxes were installed , any ground faulty's from box to box or box to ground.  or A floating ground,where the neutrals and grounds are swaped.

Bad connections in the boxes due to a salt water enviroment, again a bad ground or neutral , Have the Marina or good electrician check it out.                                                                         Make sure your wiring from the plug too the master panel are in good condition and properly connected         

Any new boats on the dock?,I had a boat tie up next with a bad grounding system , which was causing electrolisyis and eating up zinc's on my boat , he ( power boater) with an electric  stove which ended up catching fire, luckily it was put out fast.

             

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10 hours ago, garuda3 said:

There's many options to look at, How the boxes were installed , any ground faulty's from box to box or box to ground.  or A floating ground,where the neutrals and grounds are swaped.

Bad connections in the boxes due to a salt water enviroment, again a bad ground or neutral , Have the Marina or good electrician check it out.                                                                         Make sure your wiring from the plug too the master panel are in good condition and properly connected         

Any new boats on the dock?,I had a boat tie up next with a bad grounding system , which was causing electrolisyis and eating up zinc's on my boat , he ( power boater) with an electric  stove which ended up catching fire, luckily it was put out fast.

             

Yikes- I tossed and turned all night after reading... the horror...the horror... stories some of you are suggesting.  I was kind of wondering if I am in imminent danger of a fiery death or worse, having to tell my wife that I screwed something up.  Guess I'll have to meditate.  Ohm.  Ohm.  Ohm.

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Get a relatively decent Volt meter.  Hardware analog cheapie is fine.  With the boat unplugged, check the voltage from the pedestal.  Looking for 120 VAC.  IF you have 120, then plug in the boat cord and check voltage at the end of the cord.  Should also be 120 VAC.   If it is, plug in the boat and with everything turned off, check voltage at an AC outlet in the boat.   If it's substantially below 120 VAC(more than 1-2 Volts) stop there.  If it's good at 120 VAC, add a significant load in the boat.  Most portable heaters draw 13-15 amps at 120 VAC so that's a good load.  While the heater is running, check the voltage at another outlet in the string and see what you have.  

What you are doing is looking for what sounds like a voltage drop in the system.  Find that component and replace it.  From the description, I'm of the opinion you have low voltage in the boat and since other pedestals seem to work fine, the pedestal  is the likely culprit.  If it provides a voltage at 120 with no load, a loose or corroded connection may not be dealing with any significant load and you may see a voltage drop.   If the voltage at the pedestal is low under load, then stop right there and notify the marina. Don't continue to use that pedestal. If they declare it fixed, tread carefully the first time you plug in to make sure that it was properly repaired.  Lots of folks (me included) routinely play around with "low voltage" AC (120 is low voltage)and it's not risky to do that as long as you pay attention and follow good practice.  Problem with the pedestal is that it is likely served by a 200-400 amp 240 VAC circuit and screwing up and becoming the ground path for that is a life ending experience.  Leave the fix to a pro.  

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2 hours ago, Hawaiidart said:

Yikes- I tossed and turned all night after reading... the horror...the horror... stories some of you are suggesting.  I was kind of wondering if I am in imminent danger of a fiery death or worse, having to tell my wife that I screwed something up.  Guess I'll have to meditate.  Ohm.  Ohm.  Ohm.

Electrical boat heaters are right up there as the cause of burned out boats. You would be surprised how quickly things can go south. The problem with too high or low of voltage is it can negate safeties, ohms law.  Too high over designed voltage and components can burn up with out tripping breakers due to lower amperage.  To low of voltage and things can brown out and burn up under no load.  Other than the obvious fire risk replacing invertors and battery chargers can get spendy.  As I said earlier it's good to go direct to the dock with high loads, in addition to isolation if the power on the dock goes out unattended you could be running a heater off your inverter... I know this because....

Above all leave it off till you know what's what.

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1 hour ago, Innocent Bystander said:

Get a relatively decent Volt meter.  Hardware analog cheapie is fine.  With the boat unplugged, check the voltage from the pedestal.  Looking for 120 VAC.  IF you have 120, then plug in the boat cord and check voltage at the end of the cord.  Should also be 120 VAC.   If it is, plug in the boat and with everything turned off, check voltage at an AC outlet in the boat.   If it's substantially below 120 VAC(more than 1-2 Volts) stop there.  If it's good at 120 VAC, add a significant load in the boat.  Most portable heaters draw 13-15 amps at 120 VAC so that's a good load.  While the heater is running, check the voltage at another outlet in the string and see what you have.  

What you are doing is looking for what sounds like a voltage drop in the system.  Find that component and replace it.  From the description, I'm of the opinion you have low voltage in the boat and since other pedestals seem to work fine, the pedestal  is the likely culprit.  If it provides a voltage at 120 with no load, a loose or corroded connection may not be dealing with any significant load and you may see a voltage drop.   If the voltage at the pedestal is low under load, then stop right there and notify the marina. Don't continue to use that pedestal. If they declare it fixed, tread carefully the first time you plug in to make sure that it was properly repaired.  Lots of folks (me included) routinely play around with "low voltage" AC (120 is low voltage)and it's not risky to do that as long as you pay attention and follow good practice.  Problem with the pedestal is that it is likely served by a 200-400 amp 240 VAC circuit and screwing up and becoming the ground path for that is a life ending experience.  Leave the fix to a pro.  

Thank you!

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47 minutes ago, SASSAFRASS said:

Electrical boat heaters are right up there as the cause of burned out boats. You would be surprised how quickly things can go south. The problem with too high or low of voltage is it can negate safeties, ohms law.  Too high over designed voltage and components can burn up with out tripping breakers due to lower amperage.  To low of voltage and things can brown out and burn up under no load.  Other than the obvious fire risk replacing invertors and battery chargers can get spendy.  As I said earlier it's good to go direct to the dock with high loads, in addition to isolation if the power on the dock goes out unattended you could be running a heater off your inverter... I know this because....

Above all leave it off till you know what's what.


Gotcha.  Guess the heater I bought from Fisheries Supplies for boats wasn't a good idea.  I have never left it unattended, by the way.  https://www.fisheriessupply.com/caframo-true-north-electric-space-heater-9206ca-bbx

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