Okay, let's break down these electrical calculations and requirements for your new circuits in Oregon, keeping the National Electrical Code (NEC) in mind.

Microwave Circuit1. Load Calculation

Your microwave is rated for 1500W. You're correct in calculating the current draw: `I = P / V = 1500W / 120V = 12.5 Amps`

Important

The NEC (210.19(C)) requires you to size the branch circuit conductor for a microwave oven at 20 amps. This is likely due to the potential for the microwave to draw more than its nameplate rating during operation, especially during startup. This is especially important as the unit specifies that either 15A or 20A circuit is required.
2.

Wire Size and Voltage Drop

You have a 100-foot run. Voltage drop is a crucial factor over that distance. While 12 AWG might technically handle 12.5 Amps, the voltage drop could be excessive and cause the microwave to not operate efficiently or even damage it over time.

Calculating Voltage Drop

We'll use a simplified formula for estimating voltage drop: `Voltage Drop (VD) = (2 K I D) / CM` `K` = Material constant (12.9 for Copper - using copper wire) `I` = Current (12.5 Amps, but use 20 Amps for NEC requirement) `D` = One-way distance (100 feet) `CM` = Circular Mils (a measure of wire size)

For 12 AWG Copper

CM = 6530 `VD = (2 12.9 20 100) / 6530 = 7.9 Volts` `Percentage VD = (7.9V / 120V) 100 = 6.6%`

For 10 AWG Copper

CM = 10380 `VD = (2 12.9 20 100) / 10380 = 5 Volts` `Percentage VD = (5V / 120V) 100 = 4.2%`

NEC Recommendation

The NEC recommends a voltage drop of no more than 3% for branch circuits and 5% overall (from the service entrance to the furthest outlet).

Conclusion

While 10 AWG wire would significantly reduce voltage drop and is a good choice,

NEC code requires that you use 12 AWG on a 20 Amp circuit. Since you are using a 20 Amp circuit 12 AWG Copper wire is required. Using 10 AWG would be oversized, and is typically not recommended.3. Breaker Size

Use a

20 Amp breaker for this dedicated microwave circuit. This is mandated by NEC 210.19(C).
4. Receptacle

Install a standard 120V, 20A receptacle (NEMA 5-20R). This has a T-slot for the neutral pin.

Refrigerator Circuit1. Load Calculation

Refrigerator rated for 1000W - 1500W. Let's use the higher end for calculation: `I = P / V = 1500W / 120V = 12.5 Amps` Refrigerators are considered continuous loads (operate for 3 hours or more at a time). The NEC requires you to size the circuit for 125% of the continuous load. `12.5 Amps 1.25 = 15.625 Amps`2.

Existing 14/2 Wire



14 AWG wire is rated for 15 Amps. Running a potential 15.625 Amp continuous load (or even 12.5 Amps without the 125% factor) on 14 AWG wire is a fire hazard. You MUST upgrade this wire.3. Recommended Wire Size



12 AWG copper wire is recommended and required if you want to use a 20 Amp Circuit. It is rated for 20 Amps and will handle the continuous load requirement.4. Breaker Size

Use a

15 or 20 Amp breaker depending on the existing wire to the panel.

AFCI/GFCI Protection1. AFCI Protection

NEC 210.12(A) requires AFCI protection for all 120V, single-phase, 15A and 20A branch circuits supplying outlets or devices installed in dwelling units. This includes kitchen circuits. You WILL need an AFCI breaker.2.

GFCI Protection

NEC 210.8(A) requires GFCI protection for receptacles in kitchens that serve countertop surfaces. Since your microwave outlet isn't directly serving a countertop, it may not technically require GFCI protection. However, it's a good safety practice to install a GFCI breaker or outlet, especially in a kitchen. NEC 210.8(B) requires GFCI protection for receptacles in unfinished basements, garages, and outdoors, among other locations. Refrigerators are generally not recommended to be on GFCI circuits, unless specifically required by local code. The risk of nuisance tripping causing food spoilage is a concern. Many jurisdictions will allow an exception here.3.

70-Foot Rule (210.12(A)(4))

This section applies to extensions or modifications of existing circuits. If you are extending a branch circuit more than 6 feet, or modifying a branch circuit that already has AFCI protection, then the extension must also be AFCI protected. Since you're running new dedicated circuits, this doesn't apply to your specific situation.4.

Where to Install



AFCI

The AFCI breaker must be installed at the panel (where the circuit originates).

GFCI

You can use a GFCI breaker at the panel or a GFCI receptacle as the first outlet on the circuit (protecting all downstream outlets).

Dishwasher Circuit Motor Circuit? Yes, a dishwasher is considered a motor circuit. Dedicated 15 Amp Circuit

This is generally acceptable for a dishwasher, but you need to verify that the dishwasher's nameplate rating doesn't exceed 80% of the breaker rating. Also, check your local code requirements, as some jurisdictions may require a 20 Amp circuit for dishwashers.

GFCI

Dishwashers often require GFCI protection, particularly if near a sink. Check NEC 210.8(D) and local code.

Summary of Recommendations Microwave

12 AWG Copper Wire 20 Amp Breaker Standard 120V, 20A Receptacle (NEMA 5-20R) AFCI breaker at the panel. Consider GFCI for added safety.

Refrigerator

12 AWG Copper Wire 15 Amp or 20 Amp Breaker Standard 120V, 15A Receptacle (NEMA 5-15R) AFCI breaker at the panel. GFCI is generally NOT recommended, check local codes.

Dishwasher

Verify nameplate rating is within 80% of breaker rating. Check local code for GFCI requirements.

Important Reminders

Always de-energize circuits before working on them. Use appropriate electrical boxes and wiring methods. Properly ground all circuits. Call a qualified electrician if you are unsure about any aspect of this work.

Disclaimer: This information is for guidance only and should not be considered a substitute for the advice of a qualified electrician. Electrical codes vary by location and are subject to change. Always comply with all applicable codes and regulations. Improper electrical work can be dangerous and can lead to fire or electrical shock. Flag for review