[Amel Yacht Owners] Re: Prop Shaft Electrolysis


sailormon <kimberlite@...>
 

Kent,

I meant 110 volts not 10 volts.

Where are you?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Hi Kent,

If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

 

I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

 

If I am not mistaken you will still have about 10 volts between the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

 

I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

 

I am doing this from memory as I am not near the boat.

Eric

sm 376 kimberlite.


karkauai
 

I'm in Fernandina Beach, FL, Eric.
There is NO voltage between the brown wire and the green wire in the cable going to the A/C pump with the A/C breakers off.  There IS 124V AC between the brown wire and the bonding system.

I just discovered  that neither the forward A/C nor heater will come on now.  I'm guessing that's where I'll find the problem.  I need to find the 220 AC wiring diagrams for the A/Cs and the boat.
Kent
SM 243
Kristy
Tiger Point Marina
Fernandina Beach FL


On Dec 1, 2015, at 3:21 AM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I meant 110 volts not 10 volts.

Where are you?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Hi Kent,

If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

 

I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

 

If I am not mistaken you will still have about 10 volts between the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

 

I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

 

I am doing this from memory as I am not near the boat.

Eric

sm 376 kimberlite.


Bill & Judy Rouse <yahoogroups@...>
 

Kent,

I think that you just said that there is no voltage between brow and earth with the breakers off

And that there is voltage between the brown and the bonding system green/yellow under the exact same circumstances.

If this is true, I believe that your bonding system is HOT. Check between bonding system and earth (green/yellow from shore)

Bill 
BeBe 387

On Tue, Dec 1, 2015 at 12:37 PM, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I'm in Fernandina Beach, FL, Eric.
There is NO voltage between the brown wire and the green wire in the cable going to the A/C pump with the A/C breakers off.  There IS 124V AC between the brown wire and the bonding system.

I just discovered  that neither the forward A/C nor heater will come on now.  I'm guessing that's where I'll find the problem.  I need to find the 220 AC wiring diagrams for the A/Cs and the boat.
Kent
SM 243
Kristy
Tiger Point Marina
Fernandina Beach FL


On Dec 1, 2015, at 3:21 AM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I meant 110 volts not 10 volts.

Where are you?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From:< /span> amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Hi Kent,

If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

 

I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

 

If I am not mistaken you will still have about 10 volts betwee n the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

 

I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

 

I am doing this from memory as I am not near the boat.

Eric

sm 376 kimberlite.



karkauai
 

I just checked again Bill.  There is 124 VAC between either blue or brown at the pump and either the AC ground or the bonding system.  There is almost NO resistance between the AC ground and the bonding system.

There is at least a solid connection from AC ground to the bonding system.  Any idea how to figure out where that might be?

Do you know where the relay box is that powers the AC pump when the units are turned on?  That's where I think at least part of the problem lies.

Thanks again
Kent 
SM 243
Kristy 


On Dec 1, 2015, at 8:23 AM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I think that you just said that there is no voltage between brow and earth with the breakers off

And that there is voltage between the brown and the bonding system green/yellow under the exact same circumstances.

If this is true, I believe that your bonding system is HOT. Check between bonding system and earth (green/yellow from shore)

Bill 
BeBe 387

On Tue, Dec 1, 2015 at 12:37 PM, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:
 

I'm in Fernandina Beach, FL, Eric.
There is NO voltage between the brown wire and the green wire in the cable going to the A/C pump with the A/C breakers off.  There IS 124V AC between the brown wire and the bonding system.

I just discovered  that neither the forward A/C nor heater will come on now.  I'm guessing that's where I'll find the problem.  I need to find the 220 AC wiring diagrams for the A/Cs and the boat.
Kent
SM 243
Kristy
Tiger Point Marina
Fernandina Beach FL


On Dec 1, 2015, at 3:21 AM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I meant 110 volts not 10 volts.

Where are you?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From:< /span> amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Hi Kent,

If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

 

I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

 

If I am not mistaken you will still have about 10 volts betwee n the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

 

I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

 

I am doing this from memory as I am not near the boat.

Eric

sm 376 kimberlite.



James Wendell <ms42phantom54@...>
 

Kent, I have a 54, but I suspect the SM is the same. My A/C pump control box is located on the portside wall in the engine room, opposite the generator. I know because I just removed it to make room for my new inverter.
You should not have 120V unless you are connected to shore power in the US. One of the 240V legs to ground will give you 120V.
Jamie
s/v Phantom Amel 54



On Tuesday, December 1, 2015 3:09 PM, "Kent Robertson karkauai@... [amelyachtowners]" wrote:


 
I just checked again Bill.  There is 124 VAC between either blue or brown at the pump and either the AC ground or the bonding system.  There is almost NO resistance between the AC ground and the bonding system.

There is at least a solid connection from AC ground to the bonding system.  Any idea how to figure out where that might be?

Do you know where the relay box is that powers the AC pump when the units are turned on?  That's where I think at least part of the problem lies.

Thanks again
Kent 
SM 243
Kristy 


On Dec 1, 2015, at 8:23 AM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

 
Kent,

I think that you just said that there is no voltage between brow and earth with the breakers off

And that there is voltage between the brown and the bonding system green/yellow under the exact same circumstances.

If this is true, I believe that your bonding system is HOT. Check between bonding system and earth (green/yellow from shore)

Bill 
BeBe 387

On Tue, Dec 1, 2015 at 12:37 PM, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:
 
I'm in Fernandina Beach, FL, Eric.
There is NO voltage between the brown wire and the green wire in the cable going to the A/C pump with the A/C breakers off.  There IS 124V AC between the brown wire and the bonding system.

I just discovered  that neither the forward A/C nor heater will come on now.  I'm guessing that's where I'll find the problem.  I need to find the 220 AC wiring diagrams for the A/Cs and the boat.
Kent
SM 243
Kristy
Tiger Point Marina
Fernandina Beach FL


On Dec 1, 2015, at 3:21 AM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 
Kent,
I meant 110 volts not 10 volts.
Where are you?
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From:< /span> amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Hi Kent,
If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.
 
I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.
 
If I am not mistaken you will still have about 10 volts betwee n the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.
 
I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.
 
I am doing this from memory as I am not near the boat.
Eric
sm 376 kimberlite.




sailormon <kimberlite@...>
 

Jamie,

Thanks- I will look for it on Kimberlite- I thought each unit was able to turn on the motor without a relay.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Tuesday, December 01, 2015 6:55 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Kent, I have a 54, but I suspect the SM is the same. My A/C pump control box is located on the portside wall in the engine room, opposite the generator. I know because I just removed it to make room for my new inverter.

You should not have 120V unless you are connected to shore power in the US. One of the 240V legs to ground will give you 120V.

Jamie

s/v Phantom Amel 54

 

 

On Tuesday, December 1, 2015 3:09 PM, "Kent Robertson karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

I just checked again Bill.  There is 124 VAC between either blue or brown at the pump and either the AC ground or the bonding system.  There is almost NO resistance between the AC ground and the bonding system.

 

There is at least a solid connection from AC ground to the bonding system.  Any idea how to figure out where that might be?

 

Do you know where the relay box is that powers the AC pump when the units are turned on?  That's where I think at least part of the problem lies.

 

Thanks again

Kent 

SM 243

Kristy 



On Dec 1, 2015, at 8:23 AM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

 

I think that you just said that there is no voltage between brow and earth with the breakers off

 

And that there is voltage between the brown and the bonding system green/yellow under the exact same circumstances.

 

If this is true, I believe that your bonding system is HOT. Check between bonding system and earth (green/yellow from shore)

 

Bill 

BeBe 387

 

On Tue, Dec 1, 2015 at 12:37 PM, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:

 

I'm in Fernandina Beach, FL, Eric.

There is NO voltage between the brown wire and the green wire in the cable going to the A/C pump with the A/C breakers off.  There IS 124V AC between the brown wire and the bonding system.

 

I just discovered  that neither the forward A/C nor heater will come on now.  I'm guessing that's where I'll find the problem.  I need to find the 220 AC wiring diagrams for the A/Cs and the boat.

Kent

SM 243

Kristy

Tiger Point Marina

Fernandina Beach FL



On Dec 1, 2015, at 3:21 AM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Kent,

I meant 110 volts not 10 volts.

Where are you?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From:< /span> amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 30, 2015 8:17 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Hi Kent,

If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

 

I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

 

If I am not mistaken you will still have about 10 volts betwee n the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

 

I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

 

I am doing this from memory as I am not near the boat.

Eric

sm 376 kimberlite.

 

 


karkauai
 

Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy


James Wendell <ms42phantom54@...>
 

Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.

If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.

The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.

Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.

I hope that helps. Let me know what you find.

s/v Phantom Amel 54



On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" wrote:


 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy



sailormon <kimberlite@...>
 

Hi,

My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.

 

If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.

 

The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.

 

Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.

 

I hope that helps. Let me know what you find.

 

s/v Phantom Amel 54

 

 

On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy

 


James Wendell <ms42phantom54@...>
 

Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.
Can you help me here?
Jamie
s/v Phantom



On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" wrote:


 
Hi,
My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.
 
If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.
 
The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.
 
Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.
 
I hope that helps. Let me know what you find.
 
s/v Phantom Amel 54
 
 
On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy
 



Alan Leslie
 

There's a solenoid (relay) in the positive feed to the starter motor and also one in the negative feed. They both close when the start button is activated and for that brief time the battery negative is connected to the generator frame, when the generator starts and the start button is released, the realys open and the negative is isolated from the generator frame.
Its the same system on the main engine.
Cheers
Alan
Elyse SM437 


James Wendell <ms42phantom54@...>
 

Wow, I have never seen that before.
Thanks



On Thursday, December 3, 2015 2:47 PM, "divanz620@... [amelyachtowners]" wrote:


 
There's a solenoid (relay) in the positive feed to the starter motor and also one in the negative feed. They both close when the start button is activated and for that brief time the battery negative is connected to the generator frame, when the generator starts and the start button is released, the realys open and the negative is isolated from the generator frame.
Its the same system on the main engine.
Cheers
Alan
Elyse SM437 



Bill & Judy Rouse <yahoogroups@...>
 

Jamie,

Isolated ground is probably not something that you learned in electrical engineering school, but it is an important thing to understand in a marine environment. Amel uses an isolated ground system where the DC negative IS NOT part of the engine frame. You will notice this with the temperature sensor and other sensors. Most marine engines have a single wire going to the temperature sensor because the engine is ground. Your Amel has an isolated ground and there will be two wires. The only time the DC negative is connected to the starter is when the start switch is turned to start.

Your alternators will also be isolated ground alternators. I know a Bavaria owner who failed to install the correctly grounded alternator and his entire saildrive became a sacrificial chunk of metal.

As to what ABYC thinks is important, I am not so sure. Just because they are American, does not mean they are right. I would argue a number of their publications, but that is for another day and another subject.

Good luck with your new engine...did you state what engine you plan to use?

Bill
BeBe 387



On Thu, Dec 3, 2015 at 7:35 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:
 

Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.
Can you help me here?
Jamie
s/v Phantom



On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
Hi,
My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust des ign was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.
 
If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.
 
The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.
 
Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.
 
I hope that helps. Let me know what you find.
 
s/v Phantom Amel 54
 
 
On T hursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy
 




James Wendell <ms42phantom54@...>
 

Well, actually I do understand the concept of isolated ground, but I was not aware that Amel would go to the trouble of installing relays to break the DC wiring to the engine when it is shut down. There is no mention of that in any of my Amel schematics, but since I am new to this boat I still have things to learn.

And by the way, I hope I did not promote US standards as if they should be the world standard. I wish the US were on the metric system, for example, but please don't let me rant on about that one. I also wish we used single phase 230 volts like most of the rest of the world (at least Europe). There are many regs in the US that I disagree with, but electrical safety is a fairly strong one. I can see the benefit of an isolated ground from the perspective of galvanic corrosion control, but I still question the overall safety of such systems, particularly when it comes to AC earth connections.

Anyway, I have not yet selected the engine brand I will install. The easiest solution (but least desirable based on my recent disaster) would be a replacement Volvo Penta D3-110, third generation of course. That would maintain the existing systems as they are, including the isolated ground. Any other brand would have to be carefully evaluated to ensure total compatibility and to maintain the Amel way of life.

I will go check on that isolated ground everyone is talking about. Very interesting indeed.

Thanks again,
Jamie
s/v Phantom Amel 54



On Thursday, December 3, 2015 2:56 PM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" wrote:


 
Jamie,

Isolated ground is probably not something that you learned in electrical engineering school, but it is an important thing to understand in a marine environment. Amel uses an isolated ground system where the DC negative IS NOT part of the engine frame. You will notice this with the temperature sensor and other sensors. Most marine engines have a single wire going to the temperature sensor because the engine is ground. Your Amel has an isolated ground and there will be two wires. The only time the DC negative is connected to the starter is when the start switch is turned to start.

Your alternators will also be isolated ground alternators. I know a Bavaria owner who failed to install the correctly grounded alternator and his entire saildrive became a sacrificial chunk of metal.

As to what ABYC thinks is important, I am not so sure. Just because they are American, does not mean they are right. I would argue a number of their publications, but that is for another day and another subject.

Good luck with your new engine...did you state what engine you plan to use?

Bill
BeBe 387



On Thu, Dec 3, 2015 at 7:35 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:
 
Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.
Can you help me here?
Jamie
s/v Phantom



On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
Hi,
My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust des ign was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.
 
If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.
 
The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.
 
Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.
 
I hope that helps. Let me know what you find.
 
s/v Phantom Amel 54
 
 
On T hursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy
 






karkauai
 

Where is the AC ground wire connected at the generator, Eric?  

I spoke to an ONAN service guy who says that the 220AC output cable has to be connected to the housing on the generator (the box just to the port side of the bigger box with the breakers and stop switch).

He said the only way to isolate the 220AC ground from the bonding system is to remove the bonding cable from the generator.  There is a small pencil zinc in the heat exchanger that he says is enough to protect the generator.

So, is your generator connected to the bonding system?

Thanks for your thoughts Jamie. It's going to take me a while to digest that.

My brain hurts.

Kent
SM243
Kristy


On Dec 3, 2015, at 1:05 PM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Hi,

My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.

 

If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.

 

The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.

 

Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.

 

I hope that helps. Let me know what you find.

 

s/v Phantom Amel 54

 

 

On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy

 


karkauai
 

That isolates the engine's 12vDC system from the bonding system, but doesn't isolate it from the 220VAC system.
Kent 


On Dec 3, 2015, at 2:50 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Wow, I have never seen that before.
Thanks



On Thursday, December 3, 2015 2:47 PM, "divanz620@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
There's a solenoid (relay) in the positive feed to the starter motor and also one in the negative feed. They both close when the start button is activated and for that brief time the battery negative is connected to the generator frame, when the generator starts and the start button is released, the realys open and the negative is isolated from the generator frame.
Its the same system on the main engine.
Cheers
Alan
Elyse SM437 



karkauai
 

I have glo plugs on my Yanmar.  The negative connection is also made when the glo plugs are activated.  It also makes the connection when the stop solenoid is activated.
Kent 


On Dec 3, 2015, at 2:56 PM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Jamie,

Isolated ground is probably not something that you learned in electrical engineering school, but it is an important thing to understand in a marine environment. Amel uses an isolated ground system where the DC negative IS NOT part of the engine frame. You will notice this with the temperature sensor and other sensors. Most marine engines have a single wire going to the temperature sensor because the engine is ground. Your Amel has an isolated ground and there will be two wires. The only time the DC negative is connected to the starter is when the start switch is turned to start.

Your alternators will also be isolated ground alternators. I know a Bavaria owner who failed to install the correctly grounded alternator and his entire saildrive became a sacrificial chunk of metal.

As to what ABYC thinks is important, I am not so sure. Just because they are American, does not mean they are right. I would argue a number of their publications, but that is for another day and another subject.

Good luck with your new engine...did you state what engine you plan to use?

Bill
BeBe 387



On Thu, Dec 3, 2015 at 7:35 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:
 

Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.
Can you help me here?
Jamie
s/v Phantom



On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
Hi,
My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust des ign was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.
 
If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.
 
The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.
 
Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.
 
I hope that helps. Let me know what you find.
 
s/v Phantom Amel 54
 
 
On T hursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy
 




karkauai
 

I posted a schematic of the isolated ground for the engine in the files section, Jamie.
Kent


On Dec 3, 2015, at 6:15 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Well, actually I do understand the concept of isolated ground, but I was not aware that Amel would go to the trouble of installing relays to break the DC wiring to the engine when it is shut down. There is no mention of that in any of my Amel schematics, but since I am new to this boat I still have things to learn.

And by the way, I hope I did not promote US standards as if they should be the world standard. I wish the US were on the metric system, for example, but please don't let me rant on about that one. I also wish we used single phase 230 volts like most of the rest of the world (at least Europe). There are many regs in the US that I disagree with, but electrical safety is a fairly strong one. I can see the benefit of an isolated ground from the perspective of galvanic corrosion control, but I still question the overall safety of such systems, particularly when it comes to AC earth connections.

Anyway, I have not yet selected the engine brand I will install. The easiest solution (but least desirable based on my recent disaster) would be a replacement Volvo Penta D3-110, third generation of course. That would maintain the existing systems as they are, including the isolated ground. Any other brand would have to be carefully evaluated to ensure total compatibility and to maintain the Amel way of life.

I will go check on that isolated ground everyone is talking about. Very interesting indeed.

Thanks again,
Jamie
s/v Phantom Amel 54



On Thursday, December 3, 2015 2:56 PM, "'Bill & Judy Rouse' yahoogroups@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
Jamie,

Isolated ground is probably not something that you learned in electrical engineering school, but it is an important thing to understand in a marine environment. Amel uses an isolated ground system where the DC negative IS NOT part of the engine frame. You will notice this with the temperature sensor and other sensors. Most marine engines have a single wire going to the temperature sensor because the engine is ground. Your Amel has an isolated ground and there will be two wires. The only time the DC negative is connected to the starter is when the start switch is turned to start.

Your alternators will also be isolated ground alternators. I know a Bavaria owner who failed to install the correctly grounded alternator and his entire saildrive became a sacrificial chunk of metal.

As to what ABYC thinks is important, I am not so sure. Just because they are American, does not mean they are right. I would argue a number of their publications, but that is for another day and another subject.

Good luck with your new engine...did you state what engine you plan to use?

Bill
BeBe 387



On Thu, Dec 3, 2015 at 7:35 PM, James Wendell ms42phantom54@... [amelyachtowners] <amelyachtowners@...> wrote:
 
Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.
Can you help me here?
Jamie
s/v Phantom



On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" <amelyachtowners@...> wrote:


 
Hi,
My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.
Fair Winds
Eric
Kimberlite Amel Super Maramu #376
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis
 
 
Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust des ign was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.
 
If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.
 
The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.
 
Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.
 
I hope that helps. Let me know what you find.
 
s/v Phantom Amel 54
 
 
On T hursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:
 
 
Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy
 






sailormon <kimberlite@...>
 

Jamie,

If you look at the back of the generator you will see the starter solenoid. It has a floating ground as does the alternator.

It closes to connect the battery ground to the starter motor and opens as soon as the engine starts.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 2:36 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Eric, I guess I don't understand what you mean. How does the negative get disconnected after the generator starts? It would have to be connected in advance to get the starter to even work. Most negatives go directly to the generator frame which is integral with the starter.

Can you help me here?

Jamie

s/v Phantom

 

 

On Thursday, December 3, 2015 1:06 PM, "sailormon kimberlite@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

Hi,

My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.

 

If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.

 

The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.

 

Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.

 

I hope that helps. Let me know what you find.

 

s/v Phantom Amel 54

 

 

On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy

 

 


sailormon <kimberlite@...>
 

Kent,

I have to get to Colombia and check the transfer switch, generator, and the Calpeda pump.

I will then have an Idea as to what Amel did.

In Ny now.

Fair Winds

Eric

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 10:37 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Where is the AC ground wire connected at the generator, Eric?  

 

I spoke to an ONAN service guy who says that the 220AC output cable has to be connected to the housing on the generator (the box just to the port side of the bigger box with the breakers and stop switch).

 

He said the only way to isolate the 220AC ground from the bonding system is to remove the bonding cable from the generator.  There is a small pencil zinc in the heat exchanger that he says is enough to protect the generator.

 

So, is your generator connected to the bonding system?

 

Thanks for your thoughts Jamie. It's going to take me a while to digest that.

 

My brain hurts.

 

Kent

SM243

Kristy


On Dec 3, 2015, at 1:05 PM, sailormon kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Hi,

My generator has an isolated ground and the negative is not connected to the start battery except when the generator is starting.

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Thursday, December 03, 2015 9:41 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis

 

 

Kent, again thanks for the kind words about my engine failure on Phantom. Just to confirm my comments, I am not suggesting the exhaust design was necessarily at fault, but in my case the layout of the system certainly could have exacerbated my engine failure. In any event, if I can take steps to improve with my new engine, I will.

 

If I can comment on your AC findings, I understand that Amel deliberately does not connect the AC earth to the DC bonding grid. That, of course, is totally opposite from US regulations that mandate that connection for safety, a practice to which I fully subscribe as an electrical engineer. There is also the absolute "no-no" of connecting AC neutral to earth anywhere on the boat unless you have an isolation transformer.

 

The exception, however, is at a separately-derived power source. For a shore power connection, the neutral-to-earth bond would be at the shore power source in the marina. For a generator, it would be at the generator. When the automatic transfer switch (ATS) is in shore power mode, it ensures the neutral is connected only to the shore power feeder and not the boat. It also ensures the grounding systems are not interconnected, since the neutral is not connected to the boat systems. Further the generator case will be connected to earth, since the battery negative for the starter lands on the frame. When the ATS is switched to generator, the neutral "should" be tied to AC earth, since it "should" be bonded to PE at the generator. You should verify the connection between the blue neutral wire and the green/yellow PE. If it is connected you are safe; if not, and you had a fault in an AC circuit to earth, the neutral would not have a return path to its source and the AC current would try to find an alternate path - not good.

 

Many don't I know, but technically an inverter is a separately-derived power source, and the neutral there should be tied to earth as well. The problem is that most inverters also function in pass-through mode.

 

I hope that helps. Let me know what you find.

 

s/v Phantom Amel 54

 

 

On Thursday, December 3, 2015 7:42 AM, "karkauai@... [amelyachtowners]" <amelyachtowners@...> wrote:

 

 

Well, I have separated all the 220AC ground wires at the 220 box in the galley and at the 220 boxes in the engine room. I found that the output cable from the generator is grounded to the generator case, and thus, to the bonding system. The other end of that cable goes to the automatic switch that chooses generator over shore power, where it is connected to all other 220 grounds via the output from the switch.
This violates my understanding that the 220AC ground should NOT be connected to the bonding system. Now what????

Kent
SM243
Kristy