Okay, let's break down the situation and see if there's a code violation. You're concerned about the way your electrician ran MC cable horizontally through the wall cavities by cutting away drywall below the studs instead of drilling through the studs themselves.Here's the breakdown, and the likely code implications

Key Issues & Potential Violations:
Horizontal Runs Through Studs vs. Notching

The core of your concern revolves around whether the MC cable is properly protected and supported. The common (and preferred) practice, as you mentioned, is to drill holes through the center of the studs to run cable horizontally. Your electrician essentially notched the studs instead (though without actually cutting into the stud itself).

Stud Notching Limitations

This is where the problem lies. The International Residential Code (IRC), section R602.6, doesn't apply to commercial space, but the International Building Code (IBC) section 2308.6 does. The IBC section 2308.
6.1 states "Notches on the edges of joists, rafters or beams shall not exceed one-fourth the depth of the member. Holes bored in joists, rafters or beams shall not be within 2 inches (51 mm) of the top or bottom of the member, and the diameter of any such hole shall not exceed one-third the depth of the member."

Even if the inspector deemed these "studs" to be "joists" there still is an issue with the horizontal run not being supported. MC Cable Support & Protection (NEC - National Electrical Code)

This is where you're most likely going to run into a problem with the inspector, as this is the primary function of drilling the metal stud.

NEC 330.30(A)

MC cable must be supported and secured at intervals not exceeding 6 feet.

NEC 330.30(B)

MC cable must be supported and secured within 12 inches of every box, cabinet, fitting, or other termination.

NEC 300.4(D)

This is crucial for you. This section covers protection against physical damage. While MC cable itself provides a degree of protection, running it exposed in a wall cavity (especially with missing drywall) significantly increases the risk of damage from screws, nails, or other objects. While notching is not taking place, and these are not wooden studs, MC cable that is exposed is more prone to damage.

Firestopping

This is less likely to be an issue if the wall is not a fire-rated assembly. However, if the wall is a fire-rated wall, the electrician's method of cutting away sheetrock will need to be looked at by the inspector.

What to Expect from the Inspector

Given the points above, a strict inspector will likely fail the installation as it stands for the following:1.

Lack of Support

The MC cable lacks adequate support at the intervals required by the NEC.2.

Inadequate Physical Protection

The MC cable is more vulnerable to physical damage in the open wall cavity, especially with the drywall cut away. This violates NEC 300.4(D).

What to Do Now


Document Everything

Take pictures of the installation before you do anything else. This will be helpful for discussing the issue with the inspector and planning corrections.2.

Consult with the Electrician

Discuss your concerns and the potential code violations with the electrician. It's possible they have a specific reason for doing it this way (though it's unlikely to be code-compliant), or they may be willing to correct the installation.3.

Be Prepared to Correct

The most likely solution is going to be to:

Reinstate the drywall

Reinstall the drywall that was removed.

Properly Support the Cable

Securely attach the MC cable to the studs using appropriate cable supports (e.g., cable staples or straps) at the required intervals. You may need to drill through the studs to accomplish this effectively.

If the Inspector is Concerned about Firestopping

Use fire-rated sealant to seal any penetrations or gaps created by the cable installation.

In Conclusion:

While notching is likely a non-issue in your specific case due to the metal studs and the fact that your electrician did not actually notch them, you are* likely to face code violations related to cable support and protection against physical damage. Be prepared to correct the installation to meet NEC requirements, and work closely with the electrician to ensure the corrections are done properly. Flag for review