Date: Sat, 28 Sep 2002 22:22:16 +0100
From: "Alan R. Winstanley"
Subject: Re: 125 or 250V fuse?
Organization: By the light of my optical mouse...
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NNTP-Posting-Date: Sat, 28 Sep 2002 22:20:47 +0100
In article , KILOWATT
>Say two ¼ X1¼ AGC fast acting fuses.
>One is labeled 2A 125V and the other
>is 2A 250V. What should motivate me to
>choose a particular one for my project/repair
>in this case?
>Alain (alias:Kilowatt) Montreal Quebec
A definitive answer is published by Littelfuse, here:
VOLTAGE RATING: The voltage rating, as marked on a
fuse, indicates that the fuse can be relied upon to safely
interrupt its rated short circuit current in a circuit where the
voltage is equal to, or less than, its rated voltage. This system
of voltage rating is covered by N.E.C. regulations and
is a requirement of Underwriters Laboratories as a protection
against fire risk. The standard voltage ratings used by
fuse manufacturers for most small-dimension and midget
fuses are 32, 63, 125, 250 and 600.
In electronic equipment with relatively low output power
supplies, with circuit impedance limiting short circuit currents
to values of less than ten times the current rating of
the fuse, it is common practice to specify fuses with 125 or
250 volt ratings for secondary circuit protection of 500 volts
Alan Winstanley - On-Line Editor email: email@example.com
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