Whenever someone thinks they know more than the manufacturer of a device or about the codes involved, you need to be very careful that you really know what is going on before doing anything. Howard falls into this trap in the February Blue Beret when he suggests modifying Honda gensets to implement neutral to ground bonding when the small Honda 120v gensets do not have a neutral to start with.
The lesson is that you need to be very careful in listening to recommendations from ‘experts’ and make sure you really understand what is going on. Be especially careful when the experts starting tossing around ‘safety’ as the primary reason for their recommendations.
There is no need or reason for an earth ground with a portable genset. The chassis grounds of the genset and the RV are connected together by the cord and plug ground wires and that is sufficient to provide a proper frame of reference for the fault detection circuits required in modern equipment. The reason for earth grounding is with grid attached power where the earth ground, chassis ground, and neutral are connected together only at the service entrance. This is why your RV circuit box does not connect these together as it is a sub panel and not a service entrance. The grid has long transmission lines that couple it to the earth which is why it needs careful earth ground considerations. Your RV on its own, off-grid and local, power systems does not have that problem and, hence does not need earth grounding for power safety.
You do not have a safety hazard as long as the power circuit is isolated from your RV frame and the earth ground, despite what Howard says. This is why the code is as it is for small gensets or other power supply devices (like battery powered inverters).
Your 3 light circuit indicator is designed for grid power. When using small gensets with plugs, it is entirely proper for it to not show a light for hot to ground voltage as the hot and neutral sides of the power may be isolated from everything else. Like with the voltmeter, you need to use the proper test equipment and properly interpret their readings in the context of what you are doing.
The column also gets into the problem of a genset not being able to power things such as air conditioners and microwave ovens. The lesson here is to watch out for oversimplification. The reasons why a 3kW genset might not power a 1.5 kw microwave include many factors. Altitude effects on genset performance is one. The appliance power factor is another. Power startup surge might be another. Hidden loads (the fridge going to electric is a common one) can be a source of failure. Even the type and length of extension cord you use between the genset and the RV can be a factor.
When you have larger gensets or wired in gensets, then you should have a transfer switch that will automatically make the proper connections.
Note that circumstances determine how things are done. Single phase small 120v portable gensets that use plugs are not the same as house backup systems or contractor power. Sometimes you know the generator is completely independent of any other power source or not. Sometimes, especially with portable equipment, you do not know for sure it is really a ‘separately derived system.’
A 2-wire 120 volt system has no neutral and therefore bonding is optional. Recall that neither side of a 2-wire derived system is a neutral and when one grounds either side, it becomes a grounded terminal or conductor, but it is not a neutral. (OSHA 1993 clarifying letter)
Definitions of terms such as neutral and ground confuse people, too. A neutral is halfway between the two sides of a split phase 240v system, not an arbitrarily selected side of a 120v system. Chassis grounds and earth grounds are two separate things. Unless you and the expert are very careful with terms, confusion can result.
There is a lot of bad advice out there. Forums and discussion boards are particularly poor sources as they don’t do any filtering. Magazine columnists can also go astray. It is up to you to properly qualify what you find by using sound logic, gaining a proper understanding, and using multiple sources of information.
see OSHA Grounding Requirements for Portable Generators and Using Portable Generators Safely
PORTABLE GENERATORS AND OSHA CONSTRUCTION REGULATIONS is by “Grizzy” Grzywacs at the OSHA National Training Institute. He had a ‘discussion’ on RV.NET where he very patiently went over the genset grounding issues with some recalcitrant objectors and that provided a good tutorial that is summarized in the paper linked here. (the RV,NET blog has the same bad advice as the Blue Beret, though)
Solid Grounding For Your Generator thinks through some of the issues. Another EC&M column on this is about how you should treat the neutral conductor. Mike Holt also talks about the National Electric Code on Neutral to Ground connections to describe what the code says.
The IMSA describes Generator Grounding and when ground rods are required at portable generators. The article carefully describes what a “separately derived system” is with illustrations. Also note
“Portable generators are covered in Section 250.34 Portable and Vehicle-Mounted Generators. This section allows the generator or vehicle frame to serve as the grounding electrode when:
(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 the generator neutral is grounded then the generator can only be used with a transfer switch that transfers the neutral, or as a stand alone generator for a carnival or special even, and then ground rods are required.”
Generator Joe also has some good ideas for the proper operation of your portable generator.
With I’net searching, it is easy to find good resources to use to understand technical issues. Don’t get caught by bad advice, even if it does have the imprimateur of print in a journal or magazine. Electrical power is nothing to mess with so don’t think you know more than the NEC, OSHA, and the OEM unless you have the background and the resources to outweigh those authorities.