If a 24VDC power supply is not working and you measure 120V between hot and ground but 72V between hot and neutral, what is the most likely cause?

When troubleshooting a power supply, specifically when measuring voltages in an electrical system, it is essential to understand the role of each wire in the system. In this scenario, a measurement of 120V between hot and ground indicates that there is voltage present on the hot wire. However, a measurement of only 72V between hot and neutral suggests that there is a problem with the neutral connection.

In a properly functioning system, the voltage between hot and neutral should measure close to the supply voltage, which in this case would be around 120V. The fact that the measurement is significantly lower indicates an issue with the neutral wire. When the neutral wire is lost or disconnected, the voltage can become unbalanced between the hot and neutral conductors. This can lead to what is often referred to as a "floating neutral," resulting in unpredictable and incorrect voltages being read.

Hence, the most likely cause for the measurements observed — 120V between hot and ground and 72V between hot and neutral — points directly to a loss of the neutral connection. This is why this option is the correct response. A lost ground would not explain the measured voltages in this way, and the loss of hot or fuse would typically result in a complete lack of