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Hi Bill R.,
I was specifically replying to Gary Silver and his thread on the Calpeda AC Pump. It looks like his last response is imbedded below mine in my email, and my response looks like it is still attached to the main thread in my e-mail inbox. But perhaps in the forum or your email it shows up separately and would thus of course it would be difficult to see the context. As I am remote in the western Carribean, I am pretty limited to my smart phone functionality.
In one of Gary's e-mails he expressed interest in what other boats were measuring; therefore my description of measurements were in response to his measurements at the Calpeda AC sea water pump for the various conditions that I described.
When the pump was wired but switched off at the breaker I had one set of readings, another when the main 30amp GFCI was switched off, and then when I disconected the supply wires at the pump I had another set of readings on across the three wires. I think that my readings are consistent with US power supply having 220 supplied by 110 on one supply and the other 110 being supplied on the 2nd hot wire 180 degrees off phase. However, I will take your point to check the pedestal and the 60Hz shore power plug (as it was wired by the previous owner :-) )
I also agree with Danny's response supporting full disconnect at the pedistal; however in this case I did my tests carefully with power supplied in order to try to understand and provide some supportive data to Gary's observations.
Thanks and regards, Daniel Carlson on sv BeBe SM#387
On Sat, Apr 27, 2019, 11:05 AM CW Bill Rouse <brouse@...
I am a little lost as to where exactly you are measuring the voltage, but will generally respond.
Sounds to me like you could have 120v on the Earth wire (yellow/green) because you show zero between brown and blue.
- This could be caused by shore power cable/plug wired incorrectly. I have seen the Earth wire (yellow/green) connected to the center post of a USA plug rather than to the metal sleeve of the plug.
- I have also seen marina pedestals wired wrong placing voltage on Earth wire (yellow/green)
- I have also seen this happen when using a pedestal shared with another boat which is wired wrong.
I would trace starting with the pedestal connection.
CW Bill Rouse
720 Winnie St
Galveston Island, TX 77550
I am on BeBe at Red Frog Marina in Panama wit 60Hz shore power. I just checked, with all the AC breakers off but the main GFI on, and I have: 1) 120v from blue to yellow/green, as well as from brown to the yellow/green. 2) I show 0 volts AC accross the blue to brown contacts (I don't understand how you could measure 240 v across the Blue to brown when the motor is not running?). 3) when I turn of the main GFI breaker there is no voltage. I did not test the generator.
That is a shocking discovery! It would be very interesting to get confirmation of the voltages from a boat on 50 Hz supply.
One thought: Could the stray voltage be coming back from the capacitor. It shows 0 across the Blue to brow because the voltage on the blue and brown are on the same cycle when there is only one 120v source? To test this I disconnected the blue and brown wires and measured the voltage of these independently: Blue wire to yellow/green was 120v, Brown wire to yellow/green showed 39v (Stray voltage?). The voltage across the Blue to Brown was 120v.
I'm surprised this has not come up before, as it creates a very unsafe condition for one assuming the circuit is de-energized. My conclusion is to disconnect at the pedistal when working on the AC circuits to be safe.
Daniel Carlson on sv BeBe, SM#387
On Fri, Apr 19, 2019, 9:37 PM Gary Silver via Groups.Io <firstname.lastname@example.org
[Edited Message Follows]
Hi Bill and Eric:
Yes, all the 220 panel CBs are double pole (both Line [brown] and Neutral [Blue] are switched). With all breakers open (tripped) there is still 240 VAC across the blue and brown leads at the Calpeda Pump when hooked to shore power, but not when the genset is running. Looking at the Climma schematic (really more of a diagram) the neutral and safety ground wires are wire straight thru from the "separate source" and the Line [brown] from the separate source is switched by the relays to provide line voltage to the pump when a given unit is switched on. So I can see perhaps that there might be 110 voltage between the blue and safety ground at the pump from this "seperate source" but not the 220 that I am seeing. Olivier, are you there? What is the separate source for the Climma relay box?
I believe that the "other source" supply for the relay box is directly wired from the 220 volt buss just down-stream from the GFCI 30 amp breaker on the side of the 220 volt panel before it is distributed to any of the CBs (Diruptors). The difference between Euro power and US power is noted and somehow plays into this. Will continue to puzzle this out along with you. Perhaps I need to get to sail to some European power, plug in and see if the mystery voltage goes away.
Thanks for your thoughts.
Gary S. Silver
Amel SM 2000 # 335