Portable AC Generator Grounding in the bed of my pickup

pateco

pateco

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Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
uncledom said:
Charles :plus:
You turn on your gen, you plug in grandpa's steel cased antique drill, you arm/leg brushes against a water pipe that sticks out of the ground near your boat which is on the hard. There happens to be a 60 volt difference between your gen ground/neutral and the marina's ground/neutral and you get dead.
Click to expand
Yup.

BlowMeAway said:
So I think the point of this whole thread is to realize that the boat AC system is nothing more than an appliance to which an ungrounded portable generator will provide power.
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You also don't want to create a ground loop. If your bonded cast iron keel is sitting in the dirt, It can create a second ground. If the ground potential between your Generator ground and the Keel are different enough you can also be in trouble.
 
Gunni

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Charles Erwin said:
If the building transfer switch breaks the building neutral there is no longer a neutral to ground bond at the source - which is now the generator.
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OK

Charles Erwin said:
But -- if the generator is used as a portable generator (you are using an extension cord to plug into the generator receptacles) then the ground lug to earth driven ground rod is not required IF the ground and the neutral are BOTH bonded solid to the frame of the generator.
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No difference. Once you lose the neutral bond the generator frame becomes the ground. You still need a frame ground.
 
J

jeepbluetj

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Jan 18, 2016
782
Catalina 387 Dana Point
uncledom said:
Charles :plus:
You turn on your gen, you plug in grandpa's steel cased antique drill, you arm/leg brushes against a water pipe that sticks out of the ground near your boat which is on the hard. There happens to be a 60 volt difference between your gen ground/neutral and the marina's ground/neutral and you get dead.
Click to expand
How? Sitting in the bed of a truck and running stuff via an extention cord, the generator is completely isolated from the earth ground (i.e. it's floating) So there is absolutely no circuit to earth ground, no voltage potential. Only voltage is from generator hot to generator neutral/ground. So if you took grampa's steel cased drill and tossed it on some damp dirt, nothing would happen. No current would flow.

If you attach to a building, that's the case Charles Erwin describes - 'cause it's now (maybe) attached to the earth.

This is exactly what the OSHA thing posted earlier said - running via an extention cord, no ground needed. Hooked into a building's wiring you should have a ground rod.

Every RV ever made doesn't use a ground rod running a genset.

Me? I'd happily plug the boat into the generator running in the back of the truck.

Edit: - Everything I say is wrong if the keel is grounded and bonded to the 110v ground inside the boat.
 
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Bob J.

Bob J.

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Apr 14, 2009
774
Sabre 28 NH
Gunni said:
OK
No difference. Once you lose the neutral bond the generator frame becomes the ground. You still need a frame ground.
Click to expand
If that were to happen the circuit breaker on the generator would trip.
RV generators aren't grounded as others have noted, RV's sit on rubber wheels just like a pick up. Generators are used on construction sites, trust me they're not "grounded"
 
Gunni

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Misfits said:
If that were to happen the circuit breaker on the generator would trip.
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You know at 120 VAC it only takes 0.5 amps to kill a man. What amperage do you reckon the genset circuit breaker trips at?
Misfits said:
RV generators aren't grounded as others have noted, RV's sit on rubber wheels just like a pick up
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Well of course RV generators are grounded. And it has nothing to do with the wheels.
 
B

Benny17441

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May 24, 2004
7,164
CC 30 South Florida
That is the CTA sticker that the manufacturers slap on to satisfy their attorneys. Just use prudence when running the generator and do not stick a pin in the outlets. Make your connections prior to starting the generator and make sure your wiring is in good condition. Stay away from water puddles.
 
Charles Erwin

Charles Erwin

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Jan 30, 2012
1,140
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
The portable generator described here - one connected to the boat AC distribution system by a 3 wire extension cord - is no different from an on-board (Northern Lights or equivalent) generator that furnishes AC power to the boat AC distribution system. The generator is the source of AC current and that current returns to its source - the generator. Nothing 'returns' to the yard transformer (via the earth or otherwise) because the yard transformer is not the source of AC current.

The central point is that an earthing-ground (a rod in the dirt) is not involved in a portable generator/extension cord operation. AC current returns to the generating source - the generator - not to the yard transformer.

Note that a portable generator/extension cord setup is the same setup as an on-board generator - neutral and safety green are connected together at the frame of an on-board generator because the generator is where the current originates and to which it returns.

Charles

ps Gunni - a GFCI protects humans from fatal shock (5 miliamps or 5/1000 amp.) Green/white bonded at the source will not protect a human - its job is to trip a breaker in case of a dead short.
 
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Gunni

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Charles Erwin said:
The portable generator described here - one connected to the boat AC distribution system by a 3 wire extension cord - is no different from an on-board (Northern Lights or equivalent) generator that furnishes AC power to the boat AC distribution system.
Click to expand
Which makes it no different than your transfer switch example. You are connecting to, and using the vessel's electrical switching system. So you need a genset ground rod.
 
BlowMeAway

BlowMeAway

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Nov 30, 2015
1,341
Hunter 1978 H30 Cherubini, Treman Marina, Ithaca, NY
justsomeguy said:
In a controlled fashion, I actually enjoy the feel of voltage coursing through my body.
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Now your giving up your age, with Physical Therapy stimulus. Suspect shoulder issues? Me too!
 
BlowMeAway

BlowMeAway

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Nov 30, 2015
1,341
Hunter 1978 H30 Cherubini, Treman Marina, Ithaca, NY
So I got this! Plenty of dielectric between boat keel and ground. Going to the boat tomorrow after this long thunderstorm we're having this evening. Plugging the boat into the generator, in the bed of the truck, using my shore power cable. No ground rod being used...and gonna charge the batteries up. If I crisp, I'll miss you guys, if I don't I'll post a few pics.

Wayne
 
justsomeguy

justsomeguy

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Feb 20, 2011
8,048
Island Packet 35 Tucson, AZ/San Carlos, MX
BlowMeAway said:
Now your giving up your age, with Physical Therapy stimulus. Suspect shoulder issues? Me too!
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It's done purely for recreation. Health professionals go nuts when I describe the process to them.

There's a grounding wire, and a grounded wire, something that I think is not getting through to some folks.
 
Gunni

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Wayne; I am sure there is only a 1 in 25 chance that anything will happen! Good odds. Wear your rubber deck boots man, and keep your tongue off the genset frame!. Carry on.

Charles, yes I just responded to your PM.
 
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centerline

centerline

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Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Gunni said:
OK


No difference. Once you lose the neutral bond the generator frame becomes the ground. You still need a frame ground.
Click to expand
I agree... the frame almost always sits on rubber feet or rubber/plastic wheels, and this will isolate the frame from the ground. I did not read anywhere in the OSHA document that was shared that addressed this fact, but it seems they assumed the frame would be sitting on very soft ground where the rubber feet would sink in allowing the frame to come in contact with the earth, or that there is no rubber feet or wheels installed and that the metal frame will sit directly on the earth.
 
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