BasicB-003-019-011
Why do fuses have a voltage rating?
D
Answer
Basic radio theory
Type
A
To prevent dielectric breakdown of the fuse holder
B
To limit current leakage to ground while in operation
C
To ensure voltage transients can be safely dissipated
D
To specify the voltage that can be interrupted without arcing
Answer Notes
A fuse protects a circuit by melting its internal wire when the current exceeds its amperage rating, thereby breaking the circuit. However, if the voltage in the circuit is higher than the fuse's voltage rating, the electrical current can actually jump (or arc) across the physical gap left by the melted wire.
The voltage rating of a fuse specifies the maximum voltage at which the fuse can safely break the circuit without sustaining an electric arc. It does not measure the fuse's ability to dissipate transients or limit current leakage, which are completely different electrical concepts.
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On mains-operated power supplies, the ground wire of the AC line is connected to the power supply chassis. What protection does this provide if a fault occurs in the power supply?
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Why should you ground all antenna and rotator cables when your station is not in use?