Electrician's Licensing Practice Exam

Do fusing the load side of a transformer provide protection for the transformer?

1. True

2. False

3. Only in certain circumstances

4. Only if additional fuses are used

The correct answer is: False

Fusing the load side of a transformer does not provide protection for the transformer itself. The primary purpose of fuses is to protect against overloads or short circuits that may occur on the load side, which refers to the side of the transformer supplying power to the connected load. While fusing can prevent excessive current from flowing through the load, it does not inherently guard against faults that may affect the transformer directly. Transformers can experience faults such as internal short circuits, insulation failures, or overheating due to excessive voltage on the primary side. These issues can cause damage regardless of the fuses placed on the load side. For effective transformer protection, devices that detect these types of faults, such as circuit breakers, protective relays, or fuses located on the primary side, are essential. Therefore, the assertion that fusing only the load side provides adequate protection for the transformer is incorrect.