How should you proceed to replace a blown high voltage fuse?
Show the correct answer
Correct answer
B. Lower the pantograph (current collector).
Explanation
This question is about replacing a blown high-voltage fuse (fuse link). Before replacing it, you must lower the pantograph (current collector) - the answer is B.
The high-voltage fuse is in a circuit supplied from the overhead contact line. As long as the pantograph touches the contact wire, the circuit may be live at several hundred volts, which creates a risk of a fatal electric shock. Lowering the pantograph cuts the tram off from the overhead line and allows the fuse to be replaced safely. Switching off the converter alone (answer A) does not disconnect the high-voltage circuit, and gloves alone (answer C) do not ensure safety. The replacement is done following the instructions for the particular type of tram, and before the pantograph is raised again, you check that nobody is touching the equipment.
Legal basis: Art. 66 para. 1 point 1 of the Road Traffic Act (Prawo o ruchu drogowym)