Chapter 20, Problem 1RQ

To determine

The possible cause of the indication of tester (120 volts) between ungrounded (short) slot and grounded (long) slot, and also the same indication between grounded (long) slot and grounding slot (U-shaped).

Answer to Problem 1RQ

Reversed polarity at the receptacle

Explanation of Solution

In residential wiring, the duplex receptacle is the most common receptacle type. On one strap, there are two receptacles. Each receptacle can control an electrical load that is connected by a cord and plug.

A voltage tester is a device that displays estimated voltage values or simply demonstrates whether or not a voltage exists.

A voltage tester is used to evaluate a 15-ampere, 125-volt rated duplex receptacle. Between the short ungrounded and long grounded slots, the tester shows 120 volts. Between the long grounded slot and the U-shaped grounding slot, the tester shows 120 volts.

The likely cause of the indication of tester (120 volts) between ungrounded (short) slot and grounded (long) slot and also the same indication between grounded (long) slot and grounding slot (U-shaped) is Reversed polarity at the receptacle.

Conclusion:

The likely cause of the indication of tester (120 volts) between ungrounded (short) slot and grounded (long) slot and also the same indication between grounded (long) slot and grounding slot (U-shaped) is reversed polarity at the receptacle.