You can't determine how many #2 AWG THHN wires will fit in a 1" conduit based solely on the conduit size. You need to consider the fill percentage allowed by the electrical code.

Here's why:

* Conduit Fill: Electrical codes (like the National Electrical Code, or NEC) specify maximum fill percentages for conduits. This ensures there's enough space for wires to bend and move without overheating or creating pressure.

* Wire Types: Different wire types have different diameters and insulation thicknesses.

* Number of Wires: The more wires you have in a conduit, the higher the fill percentage.

To determine the correct number of wires:

1. Check the NEC: Consult the NEC tables for conduit fill percentages based on the type of wire (THHN in this case).

2. Consider Wire Size: Find the cross-sectional area of a single #2 AWG THHN wire.

3. Calculate Conduit Area: Calculate the cross-sectional area of the 1" conduit.

4. Apply Fill Percentage: Multiply the conduit area by the allowed fill percentage from the NEC table.

5. Divide by Wire Area: Divide the resulting area by the cross-sectional area of a single wire to get the maximum number of wires that can fit.

Important Notes:

* Always use the most current version of the NEC.

* Consider factors like conduit bends: Bends in the conduit reduce available space.

* Consult a qualified electrician: They can help you determine the correct wire count and ensure a safe and code-compliant installation.

Please remember that electrical work can be dangerous. If you are unsure about any aspect of wiring, consult a professional electrician.