Thread: Fuses
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Old 7th Sep 2010, 4:11 pm   #35
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Join Date: Dec 2003
Location: North London, UK.
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Default Re: Fuses

Originally Posted by Lee.Wilkerson View Post
would a 1A fuse with a 250V rating still work in a 12V position?
This is a slightly complex question.

The voltage rating of a fuse is the highest voltage at which it can be used safely. It's also usually an AC rating. The DC voltage rating will be much lower because a DC arc does not self extinguish at the zero crossovers. However a 125V or 250V fuse will be perfectly safe at 12V DC. It will not be safe at 250V DC.

Automotive fuses are rated in a somehwat different way to other types. I'll leave the explanation to those who understand this better but it may be true that a 5A automotive fuse is roughly equivalent to a 10A normal fuse.

Finally there's the surge rating. I suspect that automotive fuses are rated for pretty high surge currents. This suggests you should use "antisurge" or "slo-blo" types.
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