Basic Fuse rating question

Jul 4, 2015
414
Hunter 34 Menominee, MI; Sturgeon Bay WI
Hi;
I often find fuses rated for a different voltage than 12 volts (ie 24volts or 32 volts.) Does the rated fuse amperage need to be converted to a 12 volt rating? Thanks.
 
Dec 25, 2000
5,103
Hunter Passage 42 Shelter Bay, WA
Our boat is 12 volts throughout. Whenever I need the correct fuse, I will select one that has the correct amp rating for the application.
 
Aug 12, 2018
142
Hunter 26 Carter Lake, Colorado
Amps are amps. 10 amps at 12v hits the fuse the same as 10 amps at 120v. The power is way different (watts=amps x volts).
 

Johnb

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Jan 22, 2008
1,301
Hunter 37-cutter Richmond CA
The behavior of fuses as they are blowing is a vast topic. The most important thing is that the electrical arc that occurs as the fuse opens extinguishes within a reasonable amount of time, usually some 10's of milliseconds. For a given fuse the time will depend on the current, the voltage it is interrupting, the type of load (inductive or not) and whether the circuit is AC or DC. To protect boat wiring (not equipment) as long as the fuse is rated for more voltage than the circuit e.g. more than 12 volts, you will be O.K.

This is not to be confused with the time taken to start blowing, which is a function of fuse type and current. Fuses are broadly categorized from slow blow to ultra rapid. This another vast topic.
 
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