I'm sure you'll say no to this as well, but what about making a twistlock dummy plug that links neutral to ground at the generator's outlet? Preferabley I would use the the 240V outlet since I will never have a need for 240V. It would be plugged it prior to starting the generator and remain there until the generator is shut down (in case I wished to remove it to use the outlet).
It wouldn't be the *proper* way to do it but if it gets the job of bonding done safely and easily, whats the harm?
The way that I am going to post this will take a little understanding on your part.
What you are now thinking about as being the equipment grounding conductor (the green wire in the cord) will not be an equipment grounding conductor due to the fact that you are using a generator instead of a utility service.
To justify this statement I read 250.34(A) (2) The non–current-carrying metal parts of equipment and the
equipment grounding conductor terminals of the receptacles are bonded to the generator frame.
They are not connecting to earth.
250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor,
at each service, in accordance with 250.24(A)(1) through (A)(5).
Instead of having a grounding electrode (your tent stake) installed we are told,
250.34 Portable and Vehicle-Mounted Generators.
(A) Portable Generators. The frame of a portable generator
shall not be required to be connected to a grounding electrode as
defined in 250.52 for a system supplied by the generator under the following conditions:
(1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and
(2) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.
If we want to drive a grounding electrode we are allowed to do so as long as the electrode conforms to 250.52. This is what is meant with the use of “shall not be required†and “a grounding electrode as defined in 250.52.†Your tent stake would be nothing but a waste of time.
We also need to remember what the grounding electrode is installed for,
250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner
that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
The purpose of protecting the system from lightning is the same as it is for unintentional contact with higher-voltage lines. All of this will take place on the line side of the service and is not likely to happen to a portable generator therefore no need to have the electrode.
As to the bonding of the system; this is done to establish a path from any and all metal exposed to the touch in the system including the screws that holds device plate covers in place.
This bonding is required to occur in the service.
250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor,
at each service, in accordance with 250.24(A)(1) through (A)(5).
As outlined above the generator will not be grounded (connected to earth) instead the grounded (neutral) will be bonded to the frame.
250.34(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.
The purpose of this bonding of the neutral point (grounded point) is to establish a path back to the source from the equipment grounding terminal of the receptacle which is to be bonded to the frame of the generator.
250.34(A) (2) The non–current-carrying metal parts of equipment and the
equipment grounding conductor terminals of the receptacles are bonded to the generator frame.
This bonding to the frame makes the frame the main bonding jumper as outlined;
250.24 (B) Main Bonding Jumper. For a grounded system, an unspliced main bonding jumper shall be used to
connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28.
As outlined this bonding jumper must take place in the service equipment. The generator is the power supply and the first disconnect in its line becomes the main disconnect, the breaker or reset protecting the receptacle on the generator.
Also this bonding jumper is required to be unspliced and each place that it would plug into a receptacle would be a place that it could be broken losing the bonding. Therefore the bonding is not allowed to be done in the RV.
The bonding must take place in the service equipment and the bonding conductor must be unspliced.
This is also required when the generator is being used as a separately derived system.
250.34(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.
The generator is a separately derived system because it conforms to the definition.
Separately Derived System. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Such systems have no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.
So far we have learned that the bonding is required to be done at the generator and that a grounding electrode is not required. If the system does not have a grounding electrode then there can not be any equipment grounding conductors. The purpose of the equipment grounding conductor on a grounded (connected to earth) system;
250.130 Equipment Grounding Conductor Connections.
(A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor.
Instead of bonding to the grounding electrode conductor we are bonding to the frame. This is the only time that the green/bare conductor is an equipment bonding conductor instead of an equipment grounding conductor.
I would also wire a big tent stake to the ground terminal and to the generator's frame just to help bleed off any buildup that may occur and use a plugin GFCI adapter on the cord that plugs in the trailer.
If nothing else, that might do just until I can find someone who will actually work on the generator to bond it properly. I would hate for the generator's electrical system to be damaged by bonding it however if it's thats a possibility.
Remember that the statements above are minimum safety standards and to do anything less would be below the minimum safety standard. It is your life and the lives of your loved ones that your are trying to protect so I shall leave the rest in your hands.