Should I get scared?

[Gusshr]

I was watching some fun boat videos online about grounds and ground leak and I ended up in the boat using a clamp AMP meter reading 0.5 AMP (thats the 4 wires 2 hot, one neutral and one ground together) when all AC breakers are on running mainly the battery charger/inverter. I went to investigate further as usual, so I shut off all AC breakers including the charger/inverter supply, and with leaving only the main (shore vs Gen) selector switch on, now I measure 1.5 Amp!!! I tested the wires individually (luckily they are connected on a bus bar in the forward anchor locker) and I found out that the 1.5 Amp is measured on the white line only!!

The funny thing is that the black line is reading "0" and the red line is reading "0". Obviously the green was "0" since I have a ground isolator that I have installed when I first got the boat and it reduced the consumption of Zincs by half.

With the black and red measuring zeros, where is the 1.5 amp AC current on the neutral line coming from????!!!!

Everything on the boat was shutoff at the time of measurement.

By the way when I turn the main switch (shore vs gen) to off nothing passes and everything measure zero.

Help Please

[Gusshr]

This is an educational page about measuring the shore line AMP for leakage. https://www.marinadockage.com/techni...akage-current/

[krush]

Clamp meters are good tools. But what you are using it for is asking too much of its accuracy.

[Pete]

Take two additional measurements, leaving the "clamp on" on the white wire in the same position. First with the clamp on still reading 1.5 amps, turn off the 50 amp dual pole breaker at the pedestal serving your shore power cord. Note any change in the clamp on reading. Next, with everything remaining the same, remove your shore power cord connector from the pedestal outlet, and note what change you see, if any?

Post your results back to the group

[Gusshr]

Test results:

Main boat breaker that feeds the electrical panel is in the OFF position in all tests. Source selector switch (Gen vs Shore vs Off) is on Shore (this switch feeds the Main boat Breaker

1- with dock pedestal breaker ON, the shore cable is inserted in the pedestal, I measure 1.27 AMP on the white neutral cable as it enters the boat

2- with dock pedestal breaker OFF, the shore cable is inserted in the pedestal, I measure 1.36 AMP on the white neutral cable as it enters the boat

3- with the shore cable unplugged, I measure 0 AMP on the white neutral cable as it enters the boat.

4- with the dock pedestal breaker off I couldn't measure any voltage between any of the prongs in the receptacle!

[Gusshr]

Take two additional measurements, leaving the "clamp on" on the white wire in the same position. First with the clamp on still reading 1.5 amps, turn off the 50 amp dual pole breaker at the pedestal serving your shore power cord. Note any change in the clamp on reading. Next, with everything remaining the same, remove your shore power cord connector from the pedestal outlet, and note what change you see, if any?

Post your results back to the group

I posted the test results.Do I have a dock power problem?

[Pete]

Could be a shore power problem, but more data required for a conclusion. SAFETY, SAFETY is the primary requirement. If at any time you are not 100% positive of how to do something electrical safely, get knowledgeable help.

With that said and emphasized, the next measurement is at your pedestal service outlet. Turn off your double 50 amp pedestal breaker. Next remove your shore power cable connector from this outlet. You will now need a voltage measuring device, a separate multimeter of perhaps your clamp on also has voltage measurement scales. Whichever instrument you use, you will have two leads. Colors do not matter for this measurement. Set the scale on the instrument to "AC volts" 120 volts or next higher scale. With the pedestal 50 breaker off and your shore power cable disconnected, hold one probe with a good connection to the metal shell of the 50 amp pedestal outlet. Next, one at a time insert the second probe into the female blade terminals on the face of the pedestal. Watch for any reaction on the meter as you move the probe inside each of the terminals. Any results?

Of particular interest is the terminal that does not have a 90 degree tab. Two terminals will, these are the hot legs. One will not, this is your white wire neutral. These terminal and the outer shell tend to corrode, so be sure to get good connections with the probes. Move them around doing the measurement. All you are looking for is some sort of reaction on your meter, not a precise measurement.

[Gusshr]

Could be a shore power problem, but more data required for a conclusion. SAFETY, SAFETY is the primary requirement. If at any time you are not 100% positive of how to do something electrical safely, get knowledgeable help.

With that said and emphasized, the next measurement is at your pedestal service outlet. Turn off your double 50 amp pedestal breaker. Next remove your shore power cable connector from this outlet. You will now need a voltage measuring device, a separate multimeter of perhaps your clamp on also has voltage measurement scales. Whichever instrument you use, you will have two leads. Colors do not matter for this measurement. Set the scale on the instrument to "AC volts" 120 volts or next higher scale. With the pedestal 50 breaker off and your shore power cable disconnected, hold one probe with a good connection to the metal shell of the 50 amp pedestal outlet. Next, one at a time insert the second probe into the female blade terminals on the face of the pedestal. Watch for any reaction on the meter as you move the probe inside each of the terminals. Any results?

Of particular interest is the terminal that does not have a 90 degree tab. Two terminals will, these are the hot legs. One will not, this is your white wire neutral. These terminal and the outer shell tend to corrode, so be sure to get good connections with the probes. Move them around doing the measurement. All you are looking for is some sort of reaction on your meter, not a precise measurement.

getting zeros except between one of the hot lines with the breaker off and the ground rim getting one volt!!

[Pete]

This is now getting difficult without a wiring diagram for your boat. But lets try checking the green wire isolator. People wire many different ways, but I am not aware of any configuration that ties the green and white wire together on the boat when using shore power. So lets try this. Connect the shore power back to where you see the 1.3 amp reading on the white wire. Make sure your inverter is off. Next remove your shore power cable from the pedestal. Now connect one lead of you voltage reading meter anywhere inside the boat to the white wire. Set the voltage meter to a low voltage scale, around 5 volts,and touch the other lead to each green wire on the isolator, one at a time. If you see no reaction on the meter, change the scale to resistance on your meter set at the lowest scale. Again with one meter probe attached to the white wire touch each green wire on the isolator. Then swap the leads in the meter and try it again. Use AC and DC scales on all measurements. Yes, overkill on the various measurement but we are looking for some reaction. Does the meter react?

[Pete]

Here is a very quick but telling test. Remove your shore power cable at the boat. Leave the selector switches set for shore power as your source. Verify the inverter is off. Next choose any standard 120 volt wall outlet.

You are interested in the round ground connector and the LONGER of the two slotted connectors. The shorter of the slotted connectors is the hot lead that is not used at this time. First use your volt meter to check for any voltage between the ground connector and the longer, neutral, slotted connector. There should be none. If so, set your meter to the ohms/continuity scale and again measure between the round ground pin and the longer slotted pin. You should see no continuity/infinite ohms.

What are your results?