- Metal is an electrical conductor
- Copper is a kind of metal
- Therefore, copper is an electrical conductor

- Copper is an electrical conductor
- Wiring requires an electrical conductor
- Hence, copper can be used in wiring

Hence, copper can be used in wiring
Copper is used in house wiring because it is
- Metal is an electrical conductor 
- Copper is a kind of metal 
- Wiring requires an electrical conductor