You've hit upon a common and very valid point of concern! You are absolutely correct in your assessment. Here's a breakdown of the problem, why it's a problem, and what your options are

The Problem: Multi-Bonded Neutral
You've correctly identified it

The neutral and ground are bonded at the generator and potentially at the building's service entrance (where the normal utility connection is). This creates a parallel path for neutral current.

Why It's a Problem



Objectionable Current

Neutral current will split and flow through the ground conductor and the equipment grounding system. This is exactly what you want to avoid.

Safety Hazard

Grounding conductors aren't designed to carry significant current. They could overheat, creating a fire hazard or shock hazard.

GFCI Malfunction

Objectionable current can cause GFCI breakers to trip unnecessarily or fail to operate properly in a fault condition.

Code Violation

Most electrical codes (NEC in the US) prohibit multiple neutral-ground bonds in a system.

Measurement Complications

Finding faults becomes more difficult when you have currents flowing on the ground system.

Why Generator Manufacturers Do This (the incorrect reasoning)



Standalone Operation

Generators are often sold for standalone use (powering tools on a construction site, etc.). In this scenario, the generator must have a neutral-ground bond to ensure proper operation of overcurrent devices (breakers) in a fault condition. If there were no bond, a ground fault could exist indefinitely without tripping a breaker, creating a severe shock hazard.

Your Options and What You Should Do


Document Everything

Take photos of the neutral bonding point, the grounding system, and how everything is connected in the generator. This will be invaluable when communicating with the manufacturer.2.

Contact the Manufacturer (Politely but Firmly)

Explain the situation clearly and professionally. Reference the specific generator model and serial number. Politely explain why the current design is a problem for connection to a building with an existing grounding system. Emphasize the safety concerns and potential code violations. Suggest that they offer a field-disconnectable neutral-ground bond as an option (or standard feature) on generators intended for backup power applications. Frame it as a safety and customer service issue.

Good Example Email

Subject: Potential Safety Issue - Neutral-Ground Bonding on [Generator Model] - [Serial Number]Dear [Manufacturer Name] Support Team,I am writing to report a potential design issue regarding the neutral-ground bonding on a [Generator Model] generator, serial number [Serial Number]. I recently purchased this generator for use as a backup power source connected to a building via an Automatic Transfer Switch (ATS).During installation, I discovered that the generator's neutral output is directly bonded to the generator frame through a stud attached to the back panel of the control compartment. The output ground conductor is also connected to the same stud and the trailer frame. This creates a permanent neutral-ground bond within the generator.While I understand that a neutral-ground bond is necessary for standalone operation, in my application, where the generator is connected to a building with its own separately derived service and grounding system (non-switching ATS), this creates a parallel neutral-ground path. This can lead to objectionable current flowing through the grounding conductors, potentially causing safety hazards such as overheating, GFCI malfunction, and difficulty in fault detection. It may also be a violation of electrical codes that prohibit multiple neutral-ground bonds.I understand that the design is likely intended for standalone operation. However, I would like to suggest that you consider offering a field-disconnectable neutral-ground bond as an option or standard feature on generators intended for backup power applications. This would significantly improve the safety and usability of your generators in these types of installations.I have attached photographs illustrating the bonding configuration. I would appreciate your feedback on this matter and any potential solutions you might recommend for my specific application.Thank you for your time and attention to this important safety concern.Sincerely,[Your Name][Your Contact Information]3.

IF the manufacturer is unresponsive or unwilling to help (or if time is critical)



Consult a Licensed Electrician

Do not attempt to modify the generator's wiring yourself unless you are a qualified and licensed electrician. Incorrect modifications can be extremely dangerous and could void the generator's warranty.

If a licensed electrician deems it safe and necessary

The only way to truly eliminate the neutral-ground bond is to completely isolate the generator's neutral conductors from the frame. This might involve removing the existing neutral termination point and installing insulated standoffs to which the neutral conductors can be connected. You would then need to ensure that the grounding conductor from the generator output is securely connected to the generator frame, but is not connected to the neutral in any way. This is tricky and MUST be done by a professional. This may well require invalidating the generator warranty.

Safety Checks After Modification

If the neutral-ground bond is modified, it is critical to test the generator and the building's electrical system to ensure that everything is working safely and correctly. A licensed electrician can perform these tests.

Important Considerations Before Making ANY Changes



Warranty

Modifying the generator's wiring will almost certainly void the warranty.

Liability

If you modify the generator and someone is injured or property is damaged as a result, you could be held liable.

Code Compliance

Make sure any modifications comply with all applicable electrical codes.

In Summary:

You're right to be concerned. The generator's design, while common, is often inappropriate for backup power applications. Contact the manufacturer, document everything, and consult with a licensed electrician before making any modifications. Your diligence in identifying this issue is commendable and helps ensure the safety of yourself and others. Flag for review