Understanding 120 Volts 1 Phase 2 Wire System

What is the theoretical voltage potential between ground and neutral in a 120 volt, 1 phase, 2 wire system?

A. 120 volts

B. 0 volts

C. Less than 1 volt

D. Any significant voltage indicates a problem

Answer:

The theoretical voltage potential between ground and neutral in a 120 volt, 1 phase, 2 wire system is B. 0 volts.

In a 120 volt, 1 phase, 2 wire system, the theoretical voltage potential between the neutral and ground is zero as the neutral is grounded. In practice, a small voltage might be measured. A significant voltage indicates a problem.

In a standard 120 volt, 1 phase, 2 wire system, the voltage potential between the neutral wire and ground should theoretically be zero. This is because in a properly functioning electrical system, the neutral wire is grounded at the electrical panel, meaning it is directly connected to the earth, so there should be no difference in potential between them.

However, in practice, it's possible to measure a small voltage, typically less than 1 volt, due to electrical resistance and other factors. But any significant voltage difference between neutral and ground can indicate a problem, such as a loose neutral wire.