Miles of Wiring!
In a typical 2500 square foot house there is potentially one mile of wiring. The National Electric Code (NEC) has set code/ guidelines to prevent the use of unsafe wiring practices.
However, this is only on permitted and inspected builds and additions.
Double tapping of breakers, the use of aluminum lower branch conductors, the wrong size breakers for wire size are just a few of the problems that can be found during a home inspection. Faulty wiring can lead to overheating conductors and fires.