Okay, let's break down your plan and see if it complies with the National Electrical Code (NEC). Keep in mind that I am an AI and cannot provide legally binding advice. You should always consult with a qualified and licensed electrician in your area for installations. They can inspect the specific conditions of your property and ensure compliance with local codes, which may be more stringent than the NEC.Here's an analysis based on your description, assuming you are in the US and using the NEC

Things that look OK (based on the information you provided):
NEMA 3R Loadcenter

NEMA 3R enclosures are suitable for outdoor use, providing protection against rain. Being mounted on the brick veneer sounds acceptable, although ensure it is securely mounted and stable.

DS200H2 Hub

This hub is designed to fit your Eaton loadcenter and is appropriate for creating a weatherproof conduit entry.

#12 THWN-2 Conductors

#12 AWG copper THWN-2 conductors are suitable for 20-amp circuits. THWN-2 is rated for wet locations, which is important for conduit runs.

PVC Conduit

PVC conduit is permitted for both indoor and outdoor use and provides good physical protection.

12/2 w/g NM Cable

12/2 NM (Romex) is appropriate for the indoor portion of the circuits.

Soffit Junction Box

A junction box in the soffit space is fine, as long as it is accessible.

Potential Issues and Considerations


Conduit Fill

This is the MOST likely area for a violation. You need to ensure the conduit isn't overfilled with the 4 x #12 THWN-2 conductors. NEC Chapter 9, Table 1 specifies the maximum conduit fill. You'll need to look up the dimensions of #12 THWN-2 (likely around 0.0133 sq. in.) and calculate the total area of all 4 conductors (4 x 0.0133 = 0.0532 sq. in.). Then, you'll need to consult Chapter 9, Table 4 for PVC Conduit fill allowance. Using 1/2" PVC conduit the maximum allowable fill is 40%. Chapter 9, Table 5A shows that 1/2" PVC Conduit has an area of 0.304 sq. in. 40% of that is 0.1216 sq. in. That means you will be below the fill limit with 4 x #12 THWN-2 conductors in 1/2" PVC conduit.
2.

Conduit Support

You need to properly support the PVC conduit according to NEC 352.30. This usually involves straps or clamps every few feet.
3.

Sealing the Conduit

Even though the wires are THWN-2, you should still consider sealing the top end of the conduit where it enters the soffit to prevent moisture and insect intrusion.4.

Junction Box Accessibility

The junction box in the soffit must be accessible. NEC 314.29 states that junction boxes must be accessible without removing any part of the building finish. You can't bury it behind drywall or other permanent structures.
5.

NM Cable Protection

Where the NM cable exits the junction box and runs within the soffit, ensure it's protected from physical damage if it's exposed. This isn't as critical in a closed soffit, but if it's an open soffit, consider running the NM cable inside conduit or using cable staples to secure it along framing members.6.

GFCI Protection

Consider whether any of the circuits you are adding require GFCI protection. Common examples are outdoor receptacles or circuits serving bathrooms. The location of the receptacle (or the entire circuit) will determine if GFCI is required.7.

Weatherproofing

While THWN-2 is moisture resistant, be sure the connections within the junction box are properly made to minimize corrosion over time.

Code Sections to Reference



NEC Article 300: Wiring Methods

General requirements for wiring methods.

NEC Article 310: Conductors for General Wiring

Conductor types and ampacities.

NEC Article 314: Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures

Requirements for boxes and enclosures.

NEC Article 334: Nonmetallic-Sheathed Cable: Type NM, Type NMC, and Type NMS

Installation requirements for NM cable.

NEC Article 352: Rigid Polyvinyl Chloride Conduit: Type PVC

Installation requirements for PVC conduit.

NEC Chapter 9, Table 1 and Table 4

Conduit Fill calculations.

Recommendations


Consult a Licensed Electrician

Before you start any work, get a professional opinion. They can assess your specific situation and ensure code compliance.2.

Double-Check Conduit Fill

This is the most crucial point to verify.3.

Plan for Accessibility

Ensure the junction box remains easily accessible.4.

Use Proper Materials: Use fittings and connectors rated for the environment (e.g., weatherproof connectors for outdoor connections).By carefully considering these points and consulting with a licensed electrician, you can help ensure a safe and code-compliant installation. Good luck! Flag for review