Okay, this is a tricky situation with a lot of potential liability. Here's a breakdown of my thoughts and recommendations

Your Concerns Are Valid (and Important)
Code Violation is Likely

Your understanding of the grounding rules (EGC and Neutral separation after the main disconnect) is correct. Connecting a 3-wire range/oven to a new panel is a potential NEC violation in most jurisdictions, especially given the manufacturer's 4-wire requirement.

Safety is Paramount

The potential for a dangerous fault condition (a hot wire contacting the appliance chassis and energizing it due to an improperly connected neutral) is a serious concern. This can lead to shocks or even electrocution.

Liability Concerns

Your partner saying you're "not responsible" is naive and potentially dangerous advice. As a licensed electrician (I'm assuming you are, given you pulled a permit), you have a professional and ethical obligation to ensure safe work practices and flag potential hazards. Ignoring a code violation, even one done by others, doesn't necessarily absolve you of liability, especially if you know about it and don't take action.

Here's a Plan of Action (In Order of Priority)1. Document Everything

Immediately document everything you've observed. Include: Date and time of observations Specifics of the LG oven/microwave combo (model number, wiring configuration observed) The gauge and type of wire used for the oven/microwave circuit The fact that it was a 3-wire connection The manufacturer's 4-wire requirement (with a link to the documentation) Your concerns about the code violation and potential safety hazards Your partner's statements about not being responsible. Photos of the wiring, the panel, and the appliance label/nameplate. Who installed the original work, general contractor name, company and who performed the work on the unit.2.

Consult with a Legal Professional (Attorney) Crucial

Before doing anything else, speak with an attorney who specializes in construction law or electrical contracting issues. Explain the situation, your concerns about liability, and your desire to do the right thing. They can advise you on the best course of action to protect yourself and your business. This is not an area to guess or rely on internet advice.3.

Communicate (Carefully) with Your Partner



Reinforce the Safety Aspect

Reiterate to your partner that your concerns are primarily about safety, not just code compliance. Explain the potential for a dangerous fault condition and the risk of injury.

Document His Response

Keep a record of any conversations with your partner about this issue.4.

Consider a Written Warning to the General Contractor

I would do that only after consulting with my lawyer. Write a formal letter to the general contractor. Clearly and concisely state: The date and time you observed the LG oven/microwave combo installation. The specific 3-wire connection you observed. The LG manufacturer's requirement for a 4-wire connection. The potential safety hazards associated with the incorrect wiring. That you are notifying them of this potential hazard and urging them to have a qualified electrician inspect and correct the wiring immediately. State that you are not responsible for this other contractors work. Send the letter via certified mail with return receipt requested. Keep a copy for your records.5.

The Inspector



Before Talking to the Inspector

Get your attorney's advice. They can advise you on the best way to approach the inspector and what information to share.

When to Involve the Inspector

Typically, yes, you would want to bring this to the inspector's attention, but only after you have protected yourself legally.. They have the authority to shut down the installation until it is corrected.

Focus on the Facts

When speaking to the inspector, stick to the facts. Explain what you observed and the potential code violations. Avoid making accusations or getting into arguments.

If the Inspector Dismisses Your Concerns

Document the conversation (date, time, who you spoke with, what was said). Consider contacting the inspector's supervisor or the local building department.6.

Your Permit

The fact that your permit is for a panel upgrade doesn't completely isolate you. You are still working on the electrical system, and you have a responsibility to identify and report potential hazards. The inspector will likely look at any changes or connections made in conjunction with the panel upgrade.7.

LG and Warranty

You are absolutely right to avoid touching the appliance directly to avoid voiding the warranty. Focus on the wiring from the panel to the appliance connection point.

Important Considerations



Your Reputation

Being known as someone who prioritizes safety and code compliance is crucial for your long-term business success.

Escalation

Be prepared for the possibility that the general contractor will be resistant to correcting the wiring. You may need to escalate the issue to the building department or other authorities.

Don't Back Down on Safety

Your ethical and professional responsibility is to ensure safety. Don't let your partner pressure you into compromising your principles.

In summary, this is a situation where you need to protect yourself legally first, then proceed with notifying the appropriate parties about the safety hazard. Consulting with an attorney is paramount to ensure you are taking the right steps. Don't put your license or your conscience at risk by ignoring a known hazard. Flag for review