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Old 02-25-2013, 11:07 AM   #21
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Originally Posted by IslandEagle View Post
Actually, you can find this out pretty fast by using the tester in each outlet and seeing which GFCI pops.

Scott Welch
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Scot, you are correct if the circuit is already GFI protected. The OP was looking to add GFIs because his boat has none. He would either have to have a GFI breaker in his panel or find the first outlet to protect the circuit.
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Old 02-25-2013, 11:14 AM   #22
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My original post said to bond the ground and neutral while the noisemaker was running and lift the bond when its not running. It seems ABYC and Northern Lights at a minimum agree with me. I can live with company like that whether or not any other resident experts agree with me.
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Old 02-25-2013, 11:50 AM   #23
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Again, there is a reason why without seeing how the boat is actually wired, making advisory statements is irresponsible. We don't know to what extent some PO modified things for better or worse, what the hwole picture looks like.

By the way, here is the ABYC standard... and the variations that one must need to know:

11.5.3.2. A grounded neutral system is required.
The neutral for AC power sources shall be grounded
only at the following points:
11.5.3.2.1. The shore power neutral is
grounded through the shore power cable and shall not
be grounded on board the boat.
11.5.3.2.2. The secondary neutral of an
isolation transformer or polarization transformer shall
be grounded at the secondary of an isolation or
polarization transformer.

11.5.3.2.3. The generator neutral shall be
grounded at the generator. (See DIAGRAM 2 or
DIAGRAM 4.)
11.5.3.2.4. The inverter output neutral shall
be grounded at the inverter. The inverter output
neutral shall be disconnected from ground when the
inverter is operating in the charger or the feed-through
mode(s). (See ABYC A-25, Power Inverters.)
EXCEPTION: Exception to E-11.5.3.2.2., E-
11.5.3.2.3 and E-11.5.3.2.4: For systems using an
isolation transformer or polarization transformer,
both the generator or inverter neutral and the
transformer secondary neutrals may be grounded at
the AC main grounding bus instead of at the
generator, inverter, or transformer secondaries. (See Diagram 5)

11.5.3.3. The main AC system grounding bus shall be connected to
11.5.3.3.1. the engine negative terminal or the DC main negative bus on grounded DC systems,
11.5.3.3.2. the boat’s DC grounding bus in
1installations using ungrounded DC electrical systems.

Note that they also require any household appliances that have a neutral/ground bonding strap to have that strap disconnected (note to 11.17.3.2.)

The thought that "electricity doesn't know if it is on a boat" is a dangerous one.
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Old 02-25-2013, 11:56 AM   #24
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Quote:
Originally Posted by BobH View Post
"call in a qualified marine electrician "

Where does one find such an individual? In our area, Galveston Bay/Clear Lake, TX, I have yet to run across any marine tradesman worth a damn.

Bob
Ask around. There is a very large commercial presence there of USCG inspected boats, so there are going to be plenty of qualified electricians. One place to start might be one of the commercial electronics suppliers, like Radio Holland, see if they can refer you. Or one of the local surveyors.
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Old 02-25-2013, 12:00 PM   #25
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Originally Posted by caltexflanc View Post
Again, there is a reason why without seeing how the boat is actually wired, making advisory statements is irresponsible.
As long as the statement is polite and "nice" it doesn't matter if it is irresponsible, wrong, or even dangerous. That is an official forum rule.


Quote:
The thought that "electricity doesn't know if it is on a boat" is a dangerous one.
See above.
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Old 02-25-2013, 12:21 PM   #26
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Some place on the boat the zinc loop green wire, should be connected to the AC 110 ground already, so at the outlet its already grounded. When at dock the AC 110 ground, green wire, is the ground and when away from the dock the zinc loop, green wire, is the ground. Might want to have a marine electrician check to make sure? So there is not need to connect the gen set green wire.

It is recommend that all outlets close to s sink and outside should have a GFI. Actually you can buy a plug in GFI at Lowes/home that meets the requirements.
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Old 02-25-2013, 02:17 PM   #27
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Tell it to the folks who might know a bit more about marine generators than the average house electrician...


"There is no consensus of opinion on whether the neutral conductor should be connected to the bonding system (grounded) or not (floating ground).

Grounding the neutral may increase electrolytic corrosion. Not grounding the neutral creates a potential shock hazard. The American Boat and Yacht Council recommends grounding the neutral at the generator for safety reasons, though this may shorten the life of heat exchangers and other components. Northern Lights heartily recommends grounding the neutral since personal safety takes priority over all other considerations.

For additional electrical information, consult the AC wiring diagrams in the Generator Manual for the generator end installed on your set."
The neutral and ground should be connected together at the genset (or inverter) when one of these is supplying power. At the same time, the ground connection to shore power must be broken or there will be two grounds, a dangerous and non-code situation.

If you (and any worker, mechanic or future owner) never runs the genset or inverter while the shorepower cord is still connected there won't be a problem, but safety standards and codes are designed to protect against human error.
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Old 02-25-2013, 02:33 PM   #28
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The neutral and ground should be connected together at the genset (or inverter) when one of these is supplying power. At the same time, the ground connection to shore power must be broken or there will be two grounds, a dangerous and non-code situation.

If you (and any worker, mechanic or future owner) never runs the genset or inverter while the shorepower cord is still connected there won't be a problem, but safety standards and codes are designed to protect against human error.
The boat should have the appropriate lock outs so that can't happen, so there is only one source of power to a circuit. Better yet, isolation transformers eliminate this issue vis shorepower.

This does bring up something that I have not thought through: Some inverter manufacturers such as Victron and Mastervolt tout the ability of their inverters to add to a generator's or even shore power output in case of over load. What do they do to accomplish this safely (which I am sure they do, great companies). Again, to quote ABYC:

11.5.3.7. Individual circuits shall not be capable of being energized by more than one source of electrical power at a time. Each shore power inlet, generator, or inverter is a separate source of electrical power.
11.5.3.7.1. The transfer from one power source circuit to another shall be made by a means that opens all current-carrying conductors, including neutrals, before closing the alternate source circuit, and prevents arc-over between sources.
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Old 02-25-2013, 02:53 PM   #29
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Quote:
Originally Posted by caltexflanc View Post
This does bring up something that I have not thought through: Some inverter manufacturers such as Victron and Mastervolt tout the ability of their inverters to add to a generator's or even shore power output in case of over load. What do they do to accomplish this safely (which I am sure they do, great companies).
This is an excellent question. I have a Trace/Xatrex SW4024MC, and it does not meet this requirement. In fact, all in the 4024 all three neutrals (shore, genset, inverter) are permanently bonded in the inverter. I sort of get around the problem by using an isolation transformer and making that the sold neutral bond, but that's a pretty poor solution. I talked to an engineer at Xantrex about the problem, and they basically said "Yep, it's a problem alright. Too bad."

There's a very good article about the problem here, well worth reading: Our Odyssey-Automatic Transfer Switch

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Old 02-25-2013, 04:31 PM   #30
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Our boat has three AC outlet circuits, port, center, and starboard. All the AC putlets are the standard double receptical configuration.

The center circuit only has one outlet on it and that's in the engine room. The port outlet has two, one in the galley and one in the aft cabin. The starboard circuit has four, one in the forward cabin, one in the main cabin, one in the aft head, and one in the aft cabin.

Three of the outlets are GFI. The one on the starboard side of the main cabin, the one in the aft head (starboard), and the port outlet in the aft cabin. We have a GFI tester. In the circuit with two GFI outlets, tripping one outlet does not trip the other GFI outlet or the circuit itself. It just kills the power in the one outlet.

With regards to our generator (Onan 7.5 kw MDJE) the Onan rotary AC control switch has four positions. The two right side positions are shorepower available and shorepower connected to the AC breakers. The two left side positions are generator power available and generator power connected to the AC breakers.

This would seem to make it physically impossible for the AC circuits to be connected to both groundpower and generator power at the same time even if the generator was running at the dock with the groundpower cable connected.
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Old 02-25-2013, 04:34 PM   #31
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Quote:
Originally Posted by caltexflanc View Post
The boat should have the appropriate lock outs so that can't happen, so there is only one source of power to a circuit. .
A transfer switch should take care of this but it has to transfer all three conductors including the ground.

Unplugging the shorepower cord does the same thing, but as I posted above, there's a good chance of this not happening due to human error.
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Old 02-25-2013, 04:39 PM   #32
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Our boat has three AC outlet circuits, port, center, and starboard. All the AC putlets are the standard double receptical configuration.

The center circuit only has one outlet on it and that's in the engine room. The port outlet has two, one in the galley and one in the aft cabin. The starboard circuit has four, one in the forward cabin, one in the main cabin, one in the aft head, and one in the aft cabin.

Three of the outlets are GFI. The one on the starboard side of the main cabin, the one in the aft head (starboard), and the port outlet in the aft cabin. We have a GFI tester. In the circuit with two GFI outlets, tripping one outlet does not trip the other GFI outlet or the circuit itself. It just kills the power in the one outlet.
The easy way to fix this is to replace all the non-GFCI receptacles with GFCI receptacles. The other way (not necessarily better) is to change the wiring so the existing receptacles protect the others. You may have to move them around.

Considering the low cost of GFCI receptacles and the electrical knowledge needed to rearrange the wiring, replacing the non-GFCI receptacles with GFCI receptacles seems the better way.
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Old 02-25-2013, 04:49 PM   #33
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Fix what? There isn't a problem. We don't want the other outlets in the circuit to lose power, only the GFI outlet that gets tripped. That's how the system in our boat works now.
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Old 02-25-2013, 04:54 PM   #34
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This is what the manuel for my Xantrex Prosine inverter says.

Neutral Grounding:
a) 120V models: The neutral conductor of the AC
output circuit of the Prosine Inverter is
automatically connected to the safety ground during
inverter operation. This conforms to National
Electrical Code requirements that separately
derived AC sources (such as inverters and
generators) have their neutral conductors tied to
ground in the same way that the neutral conductor
from the utility is tied to ground at the AC breaker
panel. For models configured with a transfer relay,
when AC utility power is present and the Prosine
Inverter is in bypass mode, this connection (neutral
of the inverter‘s AC output to input safety ground)
is not present so that the utility neutral is only
connected to ground at your breaker panel, as
required.
b) 230V models: There is no connection made inside
the Prosine Inverter from either of the line
conductors (line or neutral) to the safety ground.
2.4.3 Ground Fault Circuit Interrupters
(GFCIs)
Installations in Recreational Vehicles (for North
American approvals) will require GFCI protection of
all branch circuits connected to the AC output of the
hardwire terminal equipped Prosine Inverters. In
addition, electrical codes require GFCI protection of
certain receptacles in residential installations. While
the true sine wave output of the Prosine Inverter is
equivalent to the waveform provided by utilities,
compliance with UL standards requires us to test and
recommend specific GFCIs.
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Old 02-25-2013, 05:19 PM   #35
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Fix what? There isn't a problem. We don't want the other outlets in the circuit to lose power, only the GFI outlet that gets tripped. That's how the system in our boat works now.
If you don't want to 'fix" it, why did you bother posting it at all?

My house is like that, some GFCI protected, some not. I didn't think it was worthy of a post.
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Old 02-25-2013, 05:31 PM   #36
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People were asking about the use of GFIs on boats so I simply described what our system is like in the event someone might find the description useful to what they're trying to do. I wasn't asking for a solution to a problem because we don't have one.
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Old 02-25-2013, 05:34 PM   #37
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People were asking about the use of GFIs on boats so I simply described what our system is like. I wasn't asking for a solution to a problem because we don't have one.
If you had said that, it would have saved me a lot of typing.

On the other hand, some folks may want to increase their electrical safety by protecting all the receptacles. Now they know how.

I believe that was part of the original poster's question.
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Old 02-25-2013, 07:11 PM   #38
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If you had said that, it would have saved me a lot of typing.

.
If you choose to answer a question that was never asked you've got no one to blame but yourself for the typing effort.

Other posters seemed to be saying that tripping a GFI outlet will cause other GFI outlets on the same circuit to trip as well as though it was an "always the case" situation. This is not the case on our boat which is one reason I posted our system's description.
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Old 02-25-2013, 07:18 PM   #39
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If you had said that, it would have saved me a lot of typing.
??????? I think you're wrong, Ron. I reread these posts 3 times and never came to the conclusion that Marin was stating a problem.
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Old 02-25-2013, 07:59 PM   #40
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Quote:
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If you (and any worker, mechanic or future owner) never runs the genset or inverter while the shorepower cord is still connected there won't be a problem, but safety standards and codes are designed to protect against human error.
We run shore power and a generator in parallel everytime we arrive or depart. It is called "seamless transfer" and is as common as house electricians giving bad advice to boat owners.

Doing that is not "human error" it is common practice and for the most part, completely automatic.
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