Retired EL. 208/120 Question

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livewire 41

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I'm 76 and retired. I'm at a marina and our boat uses a 2 pole 4 wire cord. The problem is the voltage from one of the poles is 140v to neutral, the other is correct at 120v to neutral. Any ideas?
Thanks.
 
O

One-eyed Jack

Senior Member
Location
Scotland Neck, NC
livewire 41 said:
I'm 76 and retired. I'm at a marina and our boat uses a 2 pole 4 wire cord. The problem is the voltage from one of the poles is 140v to neutral, the other is correct at 120v to neutral. Any ideas?
Thanks.
Click to expand...

I would say a loose neutral. Are you measuring voltage at the load end with a load? If so I can not explain the 120v side. It should be low in the amount the other is high. The neutral connections is where I would look first.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
Now Big, you know better than to jump into that Box... :confused:

Report the problem, rotate the A/C and the Refrig.

What is this, one anwser and run away?
 
G

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
100516-1846 EST

livewire 41:

Record all the following measurements.

1. At the main panel check voltage between neutral and EGC. These should be bonded at this point and the voltage difference should be very small. Without going inside my panel mine is 6 millivolts.

2. Assuming (1) is small check neutral to each line.

3. At outlets near the main panel monitor the line voltage on line A relative to neutral with and without a 1500 W heater load, about 12 A. Then switch the meter to line B and monitor while still switching the load on line A. Then vice-versa.

4. Do all of the above tests at the dock end.

With no load at the dock end the neutral to EGC should still be small. You will probably see volts of difference between neutral and EGC when a load is on one line at the dock end.

.
 
G

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
100717-0636 EST

livewire 41:

If you see something like the same voltages at the main panel, then there is a possibility of a power company source problem or the transformer that is producing the 140 V. Your thread title implies 2 phases of a 3 phase Y system that I forgot while writing my previous post. However, the tests of that post will tend to separate a wiring vs source problem.

.
 
P

poeboy

Member
Location
Los Angeles Metro area
it does seem kinda strange to have one high phase, and one normal, but since the 3rd phase is missing that could be the low one. ( I assume 3 phase cuz of the OP's name on this thread). Is it single or 3 phase coming in????

Was your boat unplugged when you took the voltage readings? if not, unplug it, then check again. The problem could be on your vessel.

Since your in a Marina its up to them to find their problem, have them call a licensed electrician to verify if its in their system or the utility.

I'm also wanting to say to be real careful with that 140 V side. A LOT of 120 Volt electronic equipment these days will burn up internally if the voltage exceeds 135 Volts.
 
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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Beware also of mistapped transformers, I found one where the Marina had a 480 volt service, then split off to several 120/208 volt transformers, apparently they were having voltage drop problems on one phase that was loaded more than the others. Instead of balancing the load, some Einstein decided to change the adjustable voltage tap on that phase only, resulting in an odd voltage combination!
 
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