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If a house has only two wires running from the power pole, what is the maximum service voltage?
120 V
240 V
60 V
480 V
The correct answer is: 120 V
In residential electrical systems, when only two wires are present, it indicates that the service is typically single-phase. The standard voltage for residential properties using a single-phase supply is 120 volts. This voltage is used for most common household devices and lighting. If there were a three-wire system present, it could provide both 120 V and 240 V, as one wire serves as the neutral, allowing for a split-phase configuration. However, with only two wires, there is no opportunity to create this split-phase, limiting the maximum service voltage to 120 V. It's essential to understand the standard configurations in residential power supply to accurately determine service voltages. In this case, since only two wires signify a single-phase connection typically used for 120 V service, this is why 120 V is identified as the maximum service voltage in this situation.